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Repository: CS193P-Translation-Group/Developing-iOS-9-Apps-with-Swift
Branch: master
Commit: 4e288f0bdac0
Files: 20
Total size: 2.3 MB
Directory structure:
gitextract_9dzbwgkv/
├── README.md
├── download.md
└── subtitles/
├── 1. Course Overview and Introduction to iOS, Xcode, and Swift.srt
├── 10. Core Data.srt
├── 11. Core Data Demo.srt
├── 12. AutoLayout.srt
├── 13. NSTimer and Animation.srt
├── 14. Animation and Core Motion.srt
├── 15. Application Lifecycle, Alerts, CloudKit.srt
├── 16. Notifications and CloudKit.srt
├── 17. Segues, Core Location, and MapKit.srt
├── 18. Persistence.srt
├── 2. Applying MVC.srt
├── 3. More Swift and Foundation Framework.srt
├── 4. Views.srt
├── 5. Interface Builder, FaceView Controller, Gestures, and Multiple MVCs.srt
├── 6. Multiple MVCs, Segues, FaceIt, and View Controller Lifecycle.srt
├── 7. Closures, Extensions, Protocols, Delegation, and ScrollView.srt
├── 8. Multithreading and Text Field.srt
└── 9. Table View.srt
================================================
FILE CONTENTS
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================================================
FILE: README.md
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Developing iOS 9 Apps with Swift 字幕简体中文翻译项目
---
iTunes U 课程地址：[iTunes U/Developing iOS 9 Apps Swift](https://itunes.apple.com/cn/course/developing-ios-9-apps-swift/id1104579961)
CS193P 课程地址：[CS193P iPhone Application Development](http://web.stanford.edu/class/cs193p/cgi-bin/drupal/)
### 相关链接
[Developing iOS 8 Apps with Swift 字幕翻译](https://github.com/X140Yu/Developing_iOS_8_Apps_With_Swift)
### 校对规则
请参见文档：[校对规则](https://github.com/X140Yu/Developing_iOS_8_Apps_With_Swift/blob/master/proofread-rules.md)。
### 字幕下载
直接点击[项目 Zip 包](https://github.com/X140Yu/Developing-iOS-9-Apps-with-Swift/archive/master.zip)进行全部已有字幕的下载。
### 视频及课件下载
[Download](./download.md)
### 联系我们
如果您想参与项目，请直接在 [Issues](https://github.com/X140Yu/Developing-iOS-9-Apps-with-Swift/issues) 区发言。
如果仅仅是想了解翻译的进度，关注项目的更新或者到 [Issues](https://github.com/X140Yu/Developing-iOS-9-Apps-with-Swift/issues) 区发言即可。
### 版权说明
The original work by Stanford University is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/3.0/us/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/">Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License</a>.
================================================
FILE: download.md
================================================
# Video
[lecture 1](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic1/v4/64/b0/84/64b084ce-11d0-a3ff-e901-bcb0b38340b9/318-3290009375018043679-01_iTunes_CS193P_03_28_16_1080_720p_1500cc.m4v)
[lecture 2](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/45/74/46/45744676-931d-e1d4-1787-952713e66c45/320-8373286204145257290-02_CS193P_3_30_16_720p1500cc.mp4)
[lecture 3](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/a8/92/8e/a8928e55-ff74-cd37-6c9d-a91d1dda2b71/309-7506772204647137370-03_CS193P_4_04_16_1080p_3mb_cc2.m4v)
[lecture 4](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/70/86/bf/7086bfd5-f133-6686-a319-7ba7947bae16/305-7247414449295650666-04_CS193P_4_06_16_1080p_3mb_cc.m4v)
[lecture 5](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/36/91/d6/3691d659-ec3b-d34f-b8ec-a92e1183095f/328-1962441713930624806-05_CS193P_4_11_16_1080p_3mb_cc.m4v)
[lecture 6](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/ab/b2/70/abb270a8-6473-7658-72b6-f614a3bd5489/333-2664853460560613531-06_CS193P_4_13_16_rev_1080p_3mb.m4v)
[lecture 7](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/81/b0/1f/81b01f26-ccd9-9df7-df6f-c5d34aea47aa/302-7208808734861639493-07_CS193__4_18_16_1080p_3mb_cc.m4v)
[lecture 8](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/99/1e/e0/991ee064-fcd4-267f-4595-361d14bc09d0/336-4841244943511706201-08_CS193_4_20_16_1080p_3mb_cc.m4v)
[lecture 9](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/b3/4f/d0/b34fd003-ee43-43dc-4b21-6c355688fb3c/311-4524248345011539875-09_CS193_4_25_16_1_1080p_3mb.m4v)
[lecture 10](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/df/93/44/df9344e9-03cf-fcfe-e550-3548d53c190d/326-7677824725330965182-10_CS193_4_27_16_1_1080p_3mb.m4v)
[lecture 11](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/d8/08/29/d80829e3-fced-1630-5942-5306cc663461/322-952121251318135044-11_CS193_5_02_16_1080p_3mb.m4v)
[lecture 12](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/64/6c/40/646c4016-9bd4-d378-a880-2ac977f38093/330-2525015638168359918-12_CS193_5_04_16_rev2_1080p_3mb.m4v)
[lecture 13](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/14/a3/b6/14a3b675-ba6c-7594-fcb7-fc0b4e82a0b7/310-1407346536923462131-13_CS193_5_09_16_1080p_3mb.m4v)
[lecture 14](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/f1/ca/44/f1ca444b-4578-8114-7297-555f4cdc9b57/326-7999025039413500594-14_CS193_5_11_16_1080p_3mb.m4v)
[lecture 15](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/80/eb/65/80eb6594-3604-9eac-1a93-187de9e32c1e/337-4900765140487554688-15_CS193_5_16_16_1080p_3mb.m4v)
[lecture 16](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/2b/9a/58/2b9a58e0-7761-b64f-45a2-2582d7f93644/324-5681395727728634007-16_CS193_5_18_16_1080p_3mb.m4v)
[lecture 17](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/bb/39/61/bb3961d5-73a0-42ec-1e71-0336508e9dfa/311-3400152801833314139-17_CS193_5_23_16_1080p_3mb.m4v)
[lecture 18](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/c8/db/e9/c8dbe99d-6f8e-28f5-47f4-ffe0c873d021/335-740161242915993166-18_CS193_5_25_16_1080p_3mb.m4v)
# Slides
[lecture 1 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic1/v4/f4/05/ff/f405ffb5-50b0-95c6-fd17-a6c262311a2d/321-5596613686960899183-CS193P_S16_Lecture_1_Slides.pdf)
[lecture 2 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/ef/31/cc/ef31cc34-7cd0-e3c4-425c-e7f75a262f00/321-3432256539360740647-CS193P_S16_Lecture_2_Slides.pdf)
[lecture 3 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/e6/a1/7e/e6a17ee2-b99f-3221-addd-da39d12d8802/321-6470380314597358395-CS193P_S16_Lecture_3_Slides.pdf)
[lecture 4 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/fb/b9/58/fbb95870-c6be-79e2-77c5-c6474b8a40bf/307-5050413922657858617-CS193P_S16_Lecture_4_Slides.pdf)
[lecture 5 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/7d/de/00/7dde003d-b32b-93fc-9786-0ec16c29ffb5/334-741241953225611839-CS193P_S16_Lecture_5_Slides.pdf)
[lecture 6 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/ae/3e/6e/ae3e6ece-fead-e585-2035-756ccd82bfd0/308-1536759857490550427-CS193P_S16_Lecture_6_Slides.pdf)
[lecture 7 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/47/02/9e/47029e12-1843-f40c-095c-ce3781137ed0/308-1708618185040143775-CS193P_S16_Lecture_7_Slides.pdf)
[lecture 8 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/57/48/6c/57486c13-678e-7892-9cb4-9dbd58ab6fae/328-2295701575035385283-CS193P_S16_Lecture_8_Slides.pdf)
[lecture 9 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/31/fb/33/31fb33c5-65ff-8e07-9c8a-2c49dd75f734/319-404525925375936666-CS193P_S16_Lecture_9_Slides.pdf)
[lecture 10 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/7c/36/24/7c36249c-605a-8fc7-5c6c-a49abe0c8d37/317-3926700305190050506-CS193P_S16_Lecture_10_Slides.pdf)
[lecture 11 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/52/74/73/52747331-a857-1914-9ebb-dc4a6dde68e7/319-3727135049627801646-CS193P_S16_Lecture_11_Slides.pdf)
[lecture 12 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/f2/9c/61/f29c6128-8f92-5c81-b1ce-6d0d62d29f0c/318-7132989426423920990-CS193P_S16_Lecture_12_Slides.pdf)
[lecture 13 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/c5/37/96/c537967b-6e29-f272-b57a-88e0ce60d531/306-350276286767890645-CS193P_S16_Lecture_13_Slides.pdf)
[lecture 14 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/9b/5e/59/9b5e5936-5126-85d4-6b18-4a13d9e7afc5/335-2050748076731576057-CS193P_S16_Lecture_14_Slides.pdf)
[lecture 15 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/55/28/db/5528dbac-7421-90ea-0d18-61d8b085e7e1/304-2868878214971040553-CS193P_S16_Lecture_15_Slides.pdf)
[lecture 16 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/42/13/f9/4213f984-9a28-80ac-8db8-b242dd377c4c/335-760378487450689313-CS193P_S16_Lecture_16_Slides.pdf)
[lecture 17 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/d8/aa/24/d8aa2482-9c87-d22a-ecec-c5bff601bc0e/322-3967892605293848768-CS193P_S16_Lecture_17_Slides.pdf)
[lecture 18 slides](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/d9/38/2c/d9382c15-0379-0000-3cbe-233ac1f92023/328-8624592354314154483-CS193P_S16_Lecture_18_Slides.pdf)
[project 1](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/8b/a7/8c/8ba78c73-a911-b9d9-7406-7b6c35b1a635/330-4665516795304515844-CS193P_S16_Programming_Project_1.pdf)
[project 2](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/62/62/f2/6262f2b4-721c-d325-3c23-ced31802068d/303-6526141645397285536-Programming_2.pdf)
[project 3](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/90/64/be/9064beaa-cc04-ad7f-30e4-a9330e21caba/320-5665175142130618734-CS193P_S16_Programming_Project_3.pdf)
[project 4](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/0b/d2/ad/0bd2ad88-4abf-29a5-b406-cefeb3637c55/315-4965520355348488665-CS193P_S16_Programming_Project_4.pdf)
[project 5](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic18/v4/e8/ba/cc/e8bacc96-9c52-8652-5613-950db7b65e5e/328-5947046615294240890-CS193P_S16_Programming_Project_5.pdf)
[project 6](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic20/v4/46/05/9a/46059aff-bffb-1dcf-00ef-0d22bad80b47/322-6708752098278348100-CS193P_S16_Programming_Project_6.pdf)
[reading 1](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic60/v4/df/8f/72/df8f7285-414d-f3f3-318a-6bb7246252b8/329-6584533342020921682-Reading_1.pdf)
[reading 2](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/32/fc/8b/32fc8b6a-bc29-8977-9035-1fc2b1b427d3/323-869352964012275742-Reading_2.pdf)
[reading 3](https://itunesu-assets.itunes.apple.com/apple-assets-us-std-000001/CobaltPublic30/v4/4a/d9/8f/4ad98f9f-18ba-7d7e-8a3e-99e8bebd2e82/313-6521184191452265856-Reading_3_2.pdf)
================================================
FILE: subtitles/1. Course Overview and Introduction to iOS, Xcode, and Swift.srt
================================================
1
00:00:00,001 --> 00:00:08,207
[SOUND] Stanford University. >> All right well welcome
斯坦福大学
2
00:00:08,209 --> 00:00:13,212
to Stanford CS193P. This is Spring of 2016 version and
欢迎来到 2016 年春季的斯坦福 CS193P 课程
3
00:00:13,214 --> 00:00:16,982
today I'm gonna give you a real quick explanation of what
今天我会快速阐述一下这门课是关于什么的
4
00:00:16,984 --> 00:00:20,986
this class is to make sure you're in the right place. I'm
以免你们来错了地方
5
00:00:20,988 --> 00:00:23,722
gonna talk about prerequisites cuz it's super important to be
也会介绍一下参加这门课程的前提
6
00:00:23,724 --> 00:00:27,159
successful in this class to have the prerequisites.
要想上好这门课，有些准备还是很重要的
7
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Then I'm just gonna give you the briefest overview of what
接着我会介绍一下 iOS 是什么
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iOS is. Most of you know because you have iPhones or
你们应该都知道
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iPads or something like that, so
因为你们用过 iPhone 或者 iPad
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I'm not gonna waste a lot of time talking about that. And
我不会在介绍 iOS 上浪费很多时间
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then finally I'm gonna dive right into a big demo that's
最后我会带你们做一个大一点的 demo
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gonna build our first application. Cuz I really
直接开始打造我们的第一个应用程序
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don't believe in wasting a lot of time with overhead.
因为我不太想花太多时间讲一些理论的知识
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00:00:45,413 --> 00:00:47,513
We're just gonna dive right in and start learning how to do
我们就直接开始上手做一些东西
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00:00:47,515 --> 00:00:51,984
this stuff, okay? We only have ten weeks to learn iOS. That's
因为我们的课程只有 10 周
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a short amount of time for it. It's a very powerful system.
对于一个这么强大的系统来说，这点学习时间太短了
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So we're gonna have to really go at break neck speed. So
所以需要以飞快的速度进行学习
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what will you learn in this class?
在这门课程中你将学到什么？
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You're gonna learn to build cool apps, all right.
你将会学到如何打造很酷的 App
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00:01:02,563 --> 00:01:05,064
iOS apps are cool. Why are they cool?
iOS App 很酷，为什么呢？
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Well, they're cool because they sit in your pocket, and
因为它们就在你的口袋里
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you can bring it out and show your friends.
你可以直接拿出来给你的朋友们看
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They're cool because they're really easy to distribute.
还有就是，App 很容易被发布
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If you build an app,
如果你开发了一款应用
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you can put it on the app store with no work. Boom,
你可以很轻松地把它放到 App Store 上
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ship it out to your customers. And also it's a very vibrant,
通过 App Store 把它移交给你的顾客
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community. All right? A lot of people doing iOS development,
iOS 开发的社区也很活跃
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and they're very excited about it.
很多人在做 iOS 开发，并且他们也很热爱
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And, also the apps that you build have animation, a lot of
App 也会包含一些很酷的动画
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really cool interactions with users, so they're fun apps to
和用户之间很炫的交互
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build. Okay, so you probably know all that,
所以制作 App 是很有趣的
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00:01:33,727 --> 00:01:36,161
that's why you're here. Another thing you're gonna
你们都知道这一点，这也是你们为什么来到这里的原因
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learn though and you're gonna get out of this class
你们还会从这门课中学到
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is real-life object-oriented programming.
面向对象编程的知识
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00:01:40,901 --> 00:01:43,569
iOS is entirely object-oriented in its design.
iOS 在设计上是完全面向对象的
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00:01:43,571 --> 00:01:46,505
All the writing of code you have to do is object-oriented
你们写的每一行代码都会是面向对象的
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programming. And you're really gonna get the experience of
你们将会从现实的面向对象编程中
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building a real-world thing using object-oriented
获得很多经验
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programming which is a great programming paradigm. And
面向对象编程也是一个很好的编程范式
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some of the things your going to learn for example using
你们将会使用
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00:01:57,284 --> 00:02:00,085
object-oriented programming. Object-oriented databases,
面向对象的数据库
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were going to do graphics with object oriented programming.
使用面向对象来编写界面
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00:02:02,523 --> 00:02:04,790
Obviously going to be some multimedia stuff,
而且还会有一些关于多媒体的东西，
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00:02:04,792 --> 00:02:06,959
multi threading, animation, networking.
多线程、动画、网络等
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00:02:06,961 --> 00:02:08,927
All kinds of stuff that you're learning in your other
你们从其它 CS 课程中学到的知识
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00:02:08,929 --> 00:02:11,163
computer science classes, you're going to do for
都会在这门课程中
47
00:02:11,165 --> 00:02:13,065
real, real life here in this class. So
得到真实的应用
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00:02:13,067 --> 00:02:15,734
that's really good, it's kind of a good synthesis class or
这很好，这就像一门综合的课程
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00:02:15,736 --> 00:02:18,570
practical synthesis class for all that stuff.
来运用你学所学到的知识
50
00:02:18,572 --> 00:02:22,908
The prerequisites are really important in this class.
这门课的前提非常重要
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The main one is object-oriented programming.
最主要的一个是面向对象编程
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00:02:25,112 --> 00:02:27,746
I really don't have time in ten weeks to take the time to
我不会在这 10 周中花时间教你们
53
00:02:27,748 --> 00:02:30,015
teach you object-oriented programming first, so
如何使用面向对象编程
54
00:02:30,017 --> 00:02:32,851
you really need to know that coming in. So in terms of
你们需要知道在这门课中会用到
55
00:02:32,853 --> 00:02:37,890
Stanford's prerequisites that means CS106A&B or CS106X.
所以在学这门课之前需要先学习 CS106A&B 或 CS106X
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00:02:37,892 --> 00:02:40,259
That's absolutely required okay, so you get some
这是必须要有的前提
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00:02:40,261 --> 00:02:44,062
Java experience in there and a little bit of object-oriented.
所以我假定你们现在有了一些 Java 的编程经验和一些面向对象的基础
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00:02:44,064 --> 00:02:47,399
And then really important to take some,
在上这门课这之前
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just some class where you're gonna do a lot of programming.
上过一些写了很多代码的课程也是很重要的
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00:02:50,204 --> 00:02:53,305
Okay like CS107 which is not hugely object-oriented but
例如 CS107，虽然没有大量关于面向对象的东西
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there's a lot of programming.
但是上那门课会写很多代码
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CS108 which is an awesome prerequisite for this class.
如果你在参加这门课之前上过 CS108 是非常好的
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Okay, that's basically object-oriented Programming.
它讲是关于面向对象编程的东西
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00:02:59,914 --> 00:03:02,548
So if you've taken CS108, you're gonna be well prepared
所以如果你上过 CS108，你就已经准备好上这门课了
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00:03:02,550 --> 00:03:05,551
for this class. CS110, again, not really object oriented
CS110，同样也没有太多关于面向对象的知识
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per-se, but there's a lot of coding in there.
但同样是一门非常好的编程课程，因为其中有大量的编程实践
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00:03:07,555 --> 00:03:10,189
You know, preferably you've taken some other CS classes,
你最好还上过其它的一些 CS 课程
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00:03:10,191 --> 00:03:12,925
you've written a lot of code because, let me warn you,
写过很多代码
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00:03:12,927 --> 00:03:16,728
this class is a lot of coding. All your assignments are all
因为上这门课需要写很多代码
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00:03:16,730 --> 00:03:19,731
coding. You're gonna write a ton of code in this class.
所有的作业都是写代码，你会在这门课中写大量的代码
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00:03:19,733 --> 00:03:22,267
So if you're not comfortable writing a ton of code,
所以如果你真的不太适应写比较多的代码
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then this class is going to be a lot of work for you.
那么这门课程对你来说将是一个挑战
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You're gonna find it, maybe you'll be a little underwater.
你会慢慢发现的
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00:03:27,641 --> 00:03:31,677
Okay so be prepared for a lot of coding.
所以做好要写很多代码的准备
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00:03:32,379 --> 00:03:33,779
When it comes to object-oriented programming,
当谈到面向对象编程
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you should know all these terms like the back of your
你就应该像了解你的手背一样了解这些术语
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hand. You shouldn't be looking at those and
你不应该连一些类似
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00:03:37,618 --> 00:03:40,652
going what, what's that, super class, I don't get it.
「父类」的术语都不懂
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00:03:40,654 --> 00:03:42,354
Okay, you should not even be here, okay.
如果是那样的话，你不应该来参加这门课程
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00:03:42,356 --> 00:03:45,691
Go take these other classes and then come back.
先去参加别的课程，然后再回来
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00:03:46,260 --> 00:03:50,062
This is an upper-level CS course, this is not 106 or
这是一门更高等级的 CS 课程
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00:03:50,064 --> 00:03:52,965
107. Okay? It's a next level up. So if you haven't
它不是 CS106 或 CS107，它是更高一级的东西
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00:03:52,967 --> 00:03:56,802
written a fairly sophisticated app before, okay, then you're
如果你还没有写过一些比较复杂的程序
84
00:03:56,804 --> 00:04:00,472
gonna find out whoa, this is a lot of work, okay. So
那你就会发现，你需要学习的东西有很多
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00:04:00,474 --> 00:04:02,674
that's the prerequisites, make sure you're prepared, for
这就是参加这门课程的条件，确定你已经准备好了
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00:04:02,676 --> 00:04:05,210
this class. And if you're not, just go take those classes and
如果没有，就先去参加其它课程，然后再回来
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come back. All right. So, what's in iOS?
什么是 iOS？
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00:04:08,182 --> 00:04:10,749
You all know what's in iOS from a user standpoint.
从一个用户的角度，你们应该都知道 iOS 是什么
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00:04:10,751 --> 00:04:12,951
I'm sure, you've used, all used iOS. So
你确定你们全都用过 iOS
90
00:04:12,953 --> 00:04:16,622
what's kinda under the covers? What are the programming APIs?
但更深层的东西是什么？编程的 API 都是什么？
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00:04:16,624 --> 00:04:19,791
Everyone know what the words API means? That basically
大家都知道 API 是什么意思
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00:04:19,793 --> 00:04:23,161
programming interface, it's the functions, and methods,
它其实就是编程接口的意思，它是使 iOS App
93
00:04:23,163 --> 00:04:26,698
and classes that we use to make an iOS app work. So
工作的函数、方法和类
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00:04:26,700 --> 00:04:30,936
what are those APIs that we use? Well they're huge. Okay,
我们能调用的 API 都有什么？它们有很多
95
00:04:30,938 --> 00:04:33,772
there's so much of it I can barely even summarize it here,
API 实在太多了，我都没办法概括出来
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but I'm gonna summarize it by dividing it into four layers
但是我可以把它分成四个层次来总结
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00:04:36,710 --> 00:04:40,445
okay? The core OS which is kind of near the hardware
Core OS 层很接近硬件
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00:04:40,447 --> 00:04:44,216
all the way up to Cocoa Touch which is near the user, okay?
Cocoa Touch 层很接近用户
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00:04:44,218 --> 00:04:46,318
And then there's some layers in between. So
在这两层之间还有一些层
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00:04:46,320 --> 00:04:46,918
let's talk about these layers,
所以我们先分层次来讨论
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00:04:46,920 --> 00:04:50,055
let's start down at the bottom there. The hardware.
先从底部开始看，硬件层
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00:04:50,057 --> 00:04:54,159
So, people don't really realize this, but an iPhone
大部分人都没有发现其实 iPhone 运行着 UNIX 系统
103
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is running Unix, okay? There's basically a version of Unix
UNIX 的最基本版本
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00:04:58,332 --> 00:05:02,567
running on it, so it has full multitasking, Unix filesystem,
所以它有多线程、UNIX 文件系统
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00:05:02,569 --> 00:05:04,303
everything in there. And, you know,
所有 UNIX 有的东西
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00:05:04,305 --> 00:05:08,206
you get the power of that when you build iOS apps, okay? And
在做 iOS 开发的时候你可以运用这些强大的能力
107
00:05:08,208 --> 00:05:09,675
that includes all these things here. Now,
iPhone 包含所有这些
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00:05:09,677 --> 00:05:12,911
there's some things that this Unix layer, that are specific
还有在 UNIX 这一层特意为了移动设备而打造的东西
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to a mobile device like Power Management is really
例如很重要的电量管理
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00:05:15,449 --> 00:05:19,351
important, Keychain Access to make sure that the people
Keychain，来管理
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are not accessing things on the phone that shouldn't,
用户在手机上不应该接触的东西
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etc. But this is basically Unix in all its glory,
但这最底层，基本上都是 UNIX 带来的光芒
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down at this low level. Next, there's a core services layer.
在它上一层，是 Core Services 层
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Because we wanna program in object-oriented programming as
因为我们在编写程序的时候尽量用到面向对象
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much as possible, there's a layer which is written in
这一层是在 UNIX 之上使用面向对象语言编写的
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object-oriented language, on top of Unix so that you can
你可以在这一层得到
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get at things like networking and multithreading and
网络、多线程
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network, or preferences and SQL for databases.
或者 SQL 数据库之类的东西
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00:05:48,515 --> 00:05:51,083
You can get at these things using object oriented APIs.
你可以通过面向对象的 API 来调用这些
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So this is kind of an object oriented layer on top of
所以这一层是在 Core Services 之上的面向对象的一层
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the core services. Okay but there is no UI in this layer.
在这一层是没有 UI(用户界面) 的
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Okay this is kind of base layer. Now the next layer,
有点像比较基础的层
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00:06:01,128 --> 00:06:04,596
super important. Ironically I don't have a lot of time to
下一个非常重要的层
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00:06:04,598 --> 00:06:07,899
talk about this in this class. I'll kind of let you know it's
我没有太多时间在课堂上介绍它
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there but it'll be something you'll have to dive into
你对这一层的了解取决你想要做些什么东西
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depending on what you want to do. But that's multimedia.
这一层就是多媒体层
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So this is video, all kinds of different audio frameworks.
在这一层，有视频、音频库
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And then of course still pictures like JPEGs,
处理例如 JPEG 图片的
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00:06:21,682 --> 00:06:22,414
things like that and
图片库
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00:06:22,416 --> 00:06:26,551
drawing okay the Quartz API for drawing in 2D. OpenGL for
用于 2D 绘图的 Quartz API
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drawing in 3D. So there's a lot of stuff here okay we
用于 3D 绘图的 OpenGL
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obviously don't have time in ten weeks to teach you OpenGL
显然在 10 周的课程之内我不会教你们 OpenGL
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you're gonna have to learn that in a graphics class but
你们需要在图形课程里学习
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you'll be able to use it here, okay.
并在那里运用
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And then at the top layer, this is where were going to
最顶层，就是我们要花几乎所有的时间在的层
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spend most of our time, is Cocoa touch, okay.
就是 Cocoa Touch 层
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It is object-oriented API for building user interfaces okay?
它提供了面向对象的 API 来搭建 UI
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And these user interfaces are not just buttons and
这些 UI 元素不仅仅包含
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sliders on the screen. But things like,
屏幕上的按扭的滑块
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00:06:52,045 --> 00:06:54,012
what to do when you shake your phone? Or
还有当你摇动手机的时候应该怎么处理
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00:06:54,014 --> 00:06:58,250
using the orientation of the phone as input for example,
或者把设备的方向当作输入
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00:06:58,252 --> 00:07:01,086
okay. It also includes animation because in iOS,
它还包含动画
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00:07:01,088 --> 00:07:04,890
in a lot of the apps there's a lot of animation going on.
因为在 iOS 中，大量的 App 使用动画
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00:07:04,892 --> 00:07:06,992
It's just part of the way it's being built and
它被搭建的时候这就是其中的一部分了
145
00:07:06,994 --> 00:07:09,461
a lot of the stuff at this level is really high
这一层的许多东西都是非常高层次的
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00:07:09,463 --> 00:07:12,264
level. Like there are objects that basically let you put
例如，你可以对一个对象进行操作
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00:07:12,266 --> 00:07:16,701
an entire Safari browser in a rectangle inside your app.
把整个 Safari 浏览器放进你 App 的一块区域中
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Okay, this one object you just drag it in,
你可以拖进来一个对象
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boom you've got it. All you have to do,
然后你就有对应的功能了
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maybe wire up the back button and you're ready to go.
你也许只需要做一个连线就可以了
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00:07:23,110 --> 00:07:26,278
Same thing with maps. You've seen the whole map 3D maps and
关于地图，你可能见过一些 2D，3D 地图
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all that stuff. Again one thing you drag it in,
同样的，你把它拖进来
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now you've got full map functionality
你就有了全部地图相关的功能
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00:07:30,818 --> 00:07:34,986
in you application. So this is super powerful objects. Again
它是非常强大的对象
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00:07:34,988 --> 00:07:37,355
in 10 weeks and I can only show you the basics of this.
在 10 周的课程内，我只能展示给你这些对象的基本用途
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Hopefully the things I've chosen to teach you
好在我选择教给你们的东西
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00:07:39,860 --> 00:07:43,261
will have paradigms for using them. That you can apply to
都有一些使用的范式
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00:07:43,263 --> 00:07:45,730
the things that I don't have time to teach you, okay.
你可以把它运用到我没有教给你的东西上面
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00:07:45,732 --> 00:07:48,033
So I'm going to try and teach you the basics
所以我会尽量教给你们让
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00:07:48,035 --> 00:07:51,436
of how to make it all work in a way that lets you go out and
这些东西基本运行起来的方式
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00:07:51,438 --> 00:07:54,973
learn new things quite straightforwardly. Okay, so
然后你们就可以通过这种方式来直接学习新的东西了
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00:07:54,975 --> 00:08:00,145
that's basically what's an iOS in three minutes or less.
所以这就是关于什么是 iOS 的小演讲
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The components of the platform that we're gonna be developing
以下这些东西是在这个平台开发所需要的
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00:08:02,850 --> 00:08:07,185
on are as follows. First, there's some tools. Really,
首先是工具
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Xcode 7 is 99% of what you're gonna be using in this class.
99% 的时间你们都要使用 Xcode 7
166
00:08:11,325 --> 00:08:13,959
Okay? It's your editor, your debugger,
它是编辑器，debug 的工具
167
00:08:13,961 --> 00:08:15,894
source code management, everything is in Xcode7,
源码管理，Xcode 7 都有
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00:08:15,896 --> 00:08:20,131
it's kind of a one stop shop. There is an extra thing there
它类似于一个一站式的工具
169
00:08:20,133 --> 00:08:22,133
instruments which kind of plugs in with Xcode7 for
Xcode 7 中还有类似于插件一样的 Instruments 工具
170
00:08:22,135 --> 00:08:24,669
doing things like performance, measurement things like that
做一些性能检测之类的事情
171
00:08:24,671 --> 00:08:27,372
but basically we're going to be in Xcode7. Okay, that's
但是基本我们会在 Xcode 7 中干活
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00:08:27,374 --> 00:08:32,344
where we're gonna be doing all our work. Language, languages,
编程语言
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there's actually two languages you can develop for
做 iOS 开发你可以使用两种语言
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00:08:34,281 --> 00:08:37,215
in iOS. We're gonna teach you the more modern one which is
我们会教你更现代的那个，Swift
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called Swift, okay? But there's another one called
另一个叫作 Objective-C
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Objective C, I'm not really gonna talk about Objective C
我不会太介绍 Objective-C
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00:08:42,189 --> 00:08:47,425
in this class, at least not primarily in the lecture. So
至少在 lecture 中不是作为主要讲解的语言
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you will have to learn a new language,
所以你得学一门新的语言
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00:08:48,962 --> 00:08:50,729
I'm sure none of you know Swift, or
我知道你们都不了解 Swift
180
00:08:50,731 --> 00:08:52,964
if you do, it's because you already know iOS.
如果你了解，是因为你对 iOS 也已经有了了解
181
00:08:52,966 --> 00:08:55,500
So Swift will be a new language you'll have to learn,
Swift 会作为你们必须要学习的新语言
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00:08:55,502 --> 00:08:57,802
I'll spend the first two weeks really trying to
前两周我会尽力用火箭一般的速度
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00:08:57,804 --> 00:09:01,406
give you rocket speed learning of this new language.
给你们讲解这门新的语言
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00:09:01,408 --> 00:09:03,275
Then there's a lot of frameworks,
然后还有大量的框架
185
00:09:03,277 --> 00:09:06,811
like foundation and UI kit which is the kinda that base
例如 Foundation 和 UIKit
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00:09:06,813 --> 00:09:09,247
core services stuff and the UI stuff, but
它们分别是核心服务和 UI 之类的东西
187
00:09:09,249 --> 00:09:12,551
there's also core data and core motion and map kit for
还有 Core Data、 Core Motion 和 MapKit
188
00:09:12,553 --> 00:09:16,087
all these things like the gyro and the accelerometer and
它们分别是对象数据库、陀螺仪和加速计
189
00:09:16,089 --> 00:09:19,724
the object database so there's a lot of frameworks and
还有地图相关的东西
190
00:09:19,726 --> 00:09:22,327
we'll cover as many of them as we can. And
还有一些其它的框架，我们将会尽可能地介绍它们
191
00:09:22,329 --> 00:09:24,229
really just as important of all these things,
还有和这些东西一样重要的一样东西
192
00:09:24,231 --> 00:09:28,667
there's a design strategy or design methodology, okay, for
就是设计 iOS 应用的一种设计策略或设计方式
193
00:09:28,669 --> 00:09:31,970
iOS called MVC, it's used on other platforms as well.
叫作 MVC，在其它平台上也有应用
194
00:09:31,972 --> 00:09:35,040
How many people here have programmed before in an MVC
有多少同学在之前使用过 MVC
195
00:09:35,042 --> 00:09:38,143
type of environment? See, so about half of you.
哦，大概一半
196
00:09:38,145 --> 00:09:40,412
Now I'm going to, since it's only half of you,
既然只有一半的人了解 MVC
197
00:09:40,414 --> 00:09:41,212
I will spend Wednesday,
在周三 lecture
198
00:09:41,214 --> 00:09:44,482
the start of the lecture, explaining MVC. Okay, how,
开始的时候，我会介绍 MVC
199
00:09:44,484 --> 00:09:49,454
what MVC is, how it applies in iOS development. But it's very
什么是 MVC，在 iOS 开发中如何运用
200
00:09:49,456 --> 00:09:51,990
important to know, it's a very important thing to know. And
这都非常重要
201
00:09:51,992 --> 00:09:55,093
I'm even going to mention it a little bit in my demo today.
我也会在今天的 demo 中介绍一些
202
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And I'll just give you the 10 second overview of
我只会给你们简单地讲述一下它
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it. Because I can't really do anything, I can't show you any
因为我还不能做任何事情
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demo without talking about MVC, it's that important.
在介绍 MVC 之前我不能做任何 demo，它就是这么重要
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Okay? So this next slide here is kind of giving you
下一张幻灯片简单地介绍了一下
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a summary of what I'm gonna show you in the demo today.
今天的这个 demo 大概要做些什么
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You don't need to read this slide now,
你现在还不需要阅读这上面的内容
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my slides will be posted for you so you'll always going to
幻灯片都会在课后发给你们
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be able to go back. This is a kind of slide you go back and
这一张就是那种课后回去阅读
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look at later to make sure, yeah did I understand that in
问问自己到底有没有看懂之类的幻灯片
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the demo, etc. Also as I'm doing the demo you'll
你们还会有我做 demo 时候的视频
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have the video of it. You'll have a video of this demo so
所以在我做 demo 的时候
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you don't need to furiously take notes or
你们不需要非常着急地记笔记
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00:10:32,199 --> 00:10:34,499
try to follow along to understand what I'm doing.
或者完全跟着我同步做
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You can watch it at your leisure later.
你可以在课后看视频
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All right, so I'm not going get back to my slides before,
在 demo 之后，就不回放之前的幻灯片了
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after the demo so let me tell you what's coming up and then
所以我先告诉你们后续会发生什么
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the rest of this is gonna be a demo. Today I have assigned
然后这门课的后半部分都会是 demo
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and it's on Piasa already, reading assignment number 1.
今天我已经把第一次作业放到 Piazza（他们的课程平台） 上了
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Okay, the reading assignments in this class are all learning
这节课的阅读作业都是关于 Swift 的
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Swift. You're gonna have three reading assignments and
一共会有三次阅读作业
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all of the three of them are gonna basically
这几次作业
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take you through the entire Swift language guide, okay. So
会让你对 Swift 有一个完整的了解
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that's what the reading assignments are all about.
阅读作业的内容就是这些
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On Wednesday, I'm gonna continue the demo that I'm
周三，我会继续进行这个 demo
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doing today. I'm gonna talk about MVC as I said and
会介绍 MVC
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then programming assignment number 1 will go out. And
第一次编程作业也会放出
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that's going to be due one week later.
一周后截至
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Before lecture the next Wednesday. On Friday we
在下周三的 lecture 之前
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have an optional section, room and time to be determined.
会有个可选的部分，时间和地点有待确定
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Probably around 1 o' clock. I'm not sure where.
也许 1 点左右，我也不太确定在哪
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This Friday's and each Friday sometimes we'll have these
有的周五都会有课
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sections, sometimes not and it's optional,
它们是可选的
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you don't have to show up if you don't want to but
你不必须参加
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00:11:38,432 --> 00:11:39,998
it's gonna be pretty valuable information.
但是课上会有很有价值的信息
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This Friday is how to use the debugger, which as you can
这个周五会介绍如何使用 debugger，还是挺有价值的内容
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imagine pretty valuable. Next Monday next week in general
下周一
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we will be doing more of the same of getting started here
会介绍如何上手
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with Swift and Xcode 7. You're, you're reading
Swift 和 Xcode 7
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assignment from today is gonna be due on Monday, and
今天的阅读作业会在周一之前截至
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then, you'll have Reading Assignment 2 go
接下来会有第二个阅读作业
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out which will be due the next Monday, so
下周一之前截至
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the Reading Assignments for the first three weeks
前三周的阅读作业
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are overlapping the Program Assignments. The first two
和编程作业是重叠的
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programing assign- assignments are quite easy. So
前两个作业是比较简单的
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there won't be a problem where you're really overloaded.
所以这些作业对于你们来说也不会显得很多
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Starting with programming assignment number 3,
第三次编程作业
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it gets quite a bit steeper, okay.
会有一个很大的跳跃
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Question? >> The programming
有问题？
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assignments, they ask you to solve specific tasks?
>> 编程作业是解决特定的编程任务吗？
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Are there any ones that are more predicted?
会有一些主观的问题吗？
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>> Yes, so the question is
>> 问题是，
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00:12:22,709 --> 00:12:24,409
do the programming assignments ask you to solve
编程作业是让你解决特定的编程任务
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a specific task, or are they kind of open-ended? And
还是有一些开放性的问题？
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the answer is the program assignments have very specific
答案是，编程作业有很明确的需求
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required tasks that you must do. You can do them any way
你可以通过任何方式完成
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00:12:33,553 --> 00:12:36,154
you want, but you must satisfy the required tasks.
但是你必须要满足指定的任务要求
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As far as open ended is, your gonna have a final project in
提到开放性任务，你们最终持续三周的项目
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three weeks, that's completely open ended.
是完全开放性的
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You get to choose entirely what you're gonna do,
你可以自己选择你想要做什么
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completely on your own, okay? If you read the document
如果你读 Piazza 上的文档
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that's on Piazza, it explains all that, okay? So for
上面就会有相关的解释了
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those of you who arrived late, read that doc,
所以对于迟到的这些同学，去读文档
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00:12:50,904 --> 00:12:54,005
get on Piazza, read it, stay on Piazza, it's all about
上 Piazza，读内容，泡在 Piazza 上
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Piazza in this class in terms of communication.
Piazza 就是用来交流的工具
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So get on there. Okay, all right,
好的
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that's it. I'm going to dive right into this demo right
我们现在开始做 demo
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here. We're going to start by launching Xcode.
先启动 Xcode
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Xcode is free, you just go to the Mac app store and
它是免费的，可以到 Mac App Store 上下载
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download it. And when you launch it, you're going to get
启动它
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this splash screen is going to appear right here. Let's hide
会显示一个启动画面
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these other things. So here's Xcode. This spash screen has
把其它的隐藏起来，这就是 Xcode
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a list of all the projects that you've been working on so
启动界面的这个列表包含你当前进行的项目
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right now we have none cuz it's the start of the quarter.
现在还没有，因为课程才刚开始
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00:13:28,542 --> 00:13:30,441
But you'll have you know each week you're gonna
但你应当知道
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00:13:30,443 --> 00:13:33,344
have more and more projects piling up in this side. And
随着课程的进行，你会有越来越多的项目
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then these three choices are the three ways to kinda
这三个选项是进入 Xcode 的三个选项
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00:13:35,749 --> 00:13:38,416
get into Xcode. 1, Here, playground,
第一个选项 playground
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that's basically, it gives you the ability to write iOS apps,
它给了你写 iOS App 的能力
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00:13:42,923 --> 00:13:45,924
and play with Xcode without building an app. Okay.
但不需要新建一个 App
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00:13:45,926 --> 00:13:49,194
So you can call APIs, put things on screen, draw things,
所以你可以调用 API，画一些控件或图形等等
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etc. It's kind of a playground for playing around with iOS.
它就像一个学习开发 iOS 应用的小训练场
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00:13:52,332 --> 00:13:54,599
We really won't be using that much in this app.
我们不会在这个 App 中使用它
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00:13:54,601 --> 00:13:57,001
But in this class, in my demos, but
但在这门课，或者 demo 中
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00:13:57,003 --> 00:13:59,404
you can certainly you're welcome to use them,
在你了解 Xcode 的过程中，
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00:13:59,406 --> 00:14:01,439
as you're playing around with Xcode.
还是欢迎你使用它的
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00:14:01,441 --> 00:14:03,508
It's kind of a fun environment. Down at
它是个很有趣的编程环境
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00:14:03,510 --> 00:14:06,911
the bottom here you can check out an existing Xcode,
在最下面，你可以添加已有
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00:14:06,913 --> 00:14:11,716
project, iOS project, that is in Source Code, management.
源码管理的 Xcode 项目
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00:14:11,718 --> 00:14:14,118
Okay, now we're going to talk about Source Code management
也许会在周五的课程中讨论源码管理
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00:14:14,120 --> 00:14:16,888
probably at a Friday section in this quarter but
但是不会在
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00:14:16,890 --> 00:14:18,122
not right at the beginning of the class.
这门课程刚开始的时候就讲
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00:14:18,124 --> 00:14:20,859
But Source Code manager is basically a way that you can
源码管理就是你可以通过类似数据库的方式
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00:14:20,861 --> 00:14:23,728
check your code in and out of like a database okay,
来管理你的源代码
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00:14:23,730 --> 00:14:27,131
so that you can work with a team, each make changes,
通过这种方式进行团队协作
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00:14:27,133 --> 00:14:28,099
merge your changes, all that stuff.
每个人对代码产生一些修改，然后合并这些修改之类的
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00:14:28,101 --> 00:14:32,370
So here is where you would check out your project to work
所以这个就是你获取已有源码管理项目的地方
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00:14:32,372 --> 00:14:36,207
on. And this middle one is to create a new Xcode project,
中间的这个是新建一个 Xcode 项目
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00:14:36,209 --> 00:14:38,176
a new Xcode App and that's we're gonna do right now,
现在就进行这一项
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00:14:38,178 --> 00:14:41,212
okay? We're gonna create from scratch a new app. Most of my
从头开始创建一个新的 App
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00:14:41,214 --> 00:14:44,449
demos involved creating an application from scratch,
几乎所有的 demo 都是从头开始创建的
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00:14:44,451 --> 00:14:45,750
okay? Just because I think it's easier for
因为在目前阶段
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00:14:45,752 --> 00:14:49,120
you to learn if there's no magic behind the scenes where
从零开始写项目
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00:14:49,122 --> 00:14:49,921
things are appearing out of nowhere. So
对你们来说更容易一些
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00:14:49,923 --> 00:14:53,658
where gonna start from scratch and go from there each time.
所以我们从头开始新建应用
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00:14:53,660 --> 00:14:55,660
All right, so I'm gonna click on this.
点这里
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00:14:55,662 --> 00:14:58,029
You can see it wants to create an app for me so
它会为我新建一个应用
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00:14:58,031 --> 00:14:59,264
it's gonna ask me some questions.
会问我几个问题
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00:14:59,266 --> 00:15:01,866
First it wants to know what kind of app I wanna build, and
首先，它问我想要创建哪种类型的应用
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00:15:01,868 --> 00:15:04,903
we wanna build an iOS application. So make sure you
我们想新建 iOS App
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00:15:04,905 --> 00:15:09,974
click iOS Application here, not watch app, or AppleTV app,
所以确认你点击了 iOS Application，而不是其它的
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00:15:09,976 --> 00:15:12,610
or an OS X app, okay? We don't want any of that.
我们不想要其它的
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00:15:12,612 --> 00:15:16,047
We want iOS application. And inside there we have some
我们想要 iOS 应用
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00:15:16,049 --> 00:15:20,652
choices of the kind of iOS app we wanna build, like a game or
在这里，它问我们想要建哪种类型的 iOS 应用
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00:15:20,654 --> 00:15:23,087
this master detail which is usually for browsing
例如是 Game 还是为了浏览数据库的 Master Detail Application
316
00:15:23,089 --> 00:15:25,890
a database. We're almost always gonna choose this one,
我们几乎只会先择这一项
317
00:15:25,892 --> 00:15:30,028
single view application. The view there is kinda referring
Single View Application，这里的 View 代表
318
00:15:30,030 --> 00:15:32,196
to the view in MVC, model view controller.
MVC 中的 V
319
00:15:32,198 --> 00:15:35,667
That design paradigm but this is the ba-, most basic
这个模板会为我们的创建最基本的
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00:15:35,669 --> 00:15:39,003
template and it gives us the least amount of code to start
MVC 骨架，它会产生最少量的代码
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00:15:39,005 --> 00:15:41,472
with, which is what we want cuz we're learning so we wanna
这也是我们希望的
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00:15:41,474 --> 00:15:44,676
write the code. We don't want it to, write any code for us.
我们正在学习，所以希望写代码的是我们，而不是 Xcode
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00:15:44,678 --> 00:15:46,678
So we're gonna pick single view template there.
所以这里选择 Single View 的模板
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00:15:46,680 --> 00:15:49,447
Now it wants to know a few things about our app,
现在它需要知道关于 App 的几点信息
325
00:15:49,449 --> 00:15:52,784
what the name of our app is, etc. The app we're going
App 的名字是什么等等
326
00:15:52,786 --> 00:15:55,853
to build today is a calculator and it's gonna look quite
今天要创建的应用是一个计算器
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00:15:55,855 --> 00:15:58,790
a bit like this calculator, not exactly the same, but
它看起来非常像一个计算器，但又不完全一致
328
00:15:58,792 --> 00:16:01,826
similar to this calculator. This is a basic calculator,
它会像这个，最基本的计算器
329
00:16:01,828 --> 00:16:04,262
it comes with Mac OS and it's gonna look like this,
是 Mac OS 上的原生应用
330
00:16:04,264 --> 00:16:06,464
it's gonna have some keypads, gonna have some operations,
它会有键盘，会有运算符
331
00:16:06,466 --> 00:16:09,867
gonna have a little display in here. Basically a calculator,
在这里还会有个小显示器
332
00:16:09,869 --> 00:16:11,336
so I'm gonna call my app calculator.
所以给我的 App 起名为 calculator
333
00:16:11,338 --> 00:16:13,938
So that's the name of this app. When I look at it on my
它就是 App 的名字，当我在手机上查看它的时候
334
00:16:13,940 --> 00:16:16,074
phone it's gonna say calculator is the name of it.
上面显示的名字就会是 calculator
335
00:16:16,076 --> 00:16:19,010
Okay? This organization name can be anything you want.
这个组织名你可以随意填
336
00:16:19,012 --> 00:16:22,880
It's basically gonna appear in the copyright of your code.
它会显示在你代码的版权信息上
337
00:16:22,882 --> 00:16:23,748
Okay? When you write code,
当你写代码的时候
338
00:16:23,750 --> 00:16:25,116
at the top it's gonna say copyright,
在最上面会显示版权信息
339
00:16:25,118 --> 00:16:26,718
whatever you put here. Put whatever you want.
你可以在这里放什么都行
340
00:16:26,720 --> 00:16:28,953
Your name or whatever. This however,
姓名之类的
341
00:16:28,955 --> 00:16:33,925
wants to uniquely identify you, okay, as a developer. And
这里，需要一个不重复的标识
342
00:16:33,927 --> 00:16:36,728
a good way to do it is this reverse DNS notation here,
一个解决这个问题的很好方式是这个逆向的 DNS 标志
343
00:16:36,730 --> 00:16:40,698
edu.stanford.cs193p and then instead of putting instructor,
edu.stanford.cs193p
344
00:16:40,700 --> 00:16:44,268
put your SU net ID. Cuz no one else has that.
在 instructor 那里填上你的学号就好，因为这不会重复
345
00:16:44,270 --> 00:16:46,304
This would uniquely identify you in the universe.
这会在宇宙中唯一确定你
346
00:16:46,306 --> 00:16:49,407
No one else is going to have that organization identifier.
没人会跟你重复的
347
00:16:49,409 --> 00:16:50,875
And then it builds a unique
随后它会产生一个独一无二的标识
348
00:16:50,877 --> 00:16:54,679
identifier from the app by combining these two things.
通过把这两个结合起来的方式
349
00:16:54,681 --> 00:16:57,315
Okay? You get to choose the language you want to program
在这里选择你想要编程的语言
350
00:16:57,317 --> 00:17:00,385
in here. It actually doesn't matter what you choose
在这里选择什么无关紧要
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00:17:00,387 --> 00:17:03,154
here, this is just going to be the language that the initial
它只会为你创建
352
00:17:03,156 --> 00:17:05,723
template is going to give you it starts out in.
相关语言的初始模板
353
00:17:05,725 --> 00:17:07,525
You can freely mix Objective C and
在写 iOS 应用的时候
354
00:17:07,527 --> 00:17:10,561
Swift when you're building IOS apps. Okay? Back and
你可以把 Swift 和 Objective-C 混合起来
355
00:17:10,563 --> 00:17:13,364
forth they're, you don't have to pick one and be stuck with
你不需要在选择完一个之后就卡在这了
356
00:17:13,366 --> 00:17:16,234
it. We're going to do all of our programming in this class
在这门课中我们所有的编程都会使用 Swift
357
00:17:16,236 --> 00:17:19,570
in Swift however. Then this is whether we want
这里决定我们是要搭建一个
358
00:17:19,572 --> 00:17:21,139
to build an iPhone only calculator.
专属 iPhone 的
359
00:17:21,141 --> 00:17:24,909
An iPad only calculator. Or a universal calculator that will
还是 iPad 的
360
00:17:24,911 --> 00:17:27,979
work on either iPad or iPhone. Okay? And
或者是它们都可以使用的计算器
361
00:17:27,981 --> 00:17:30,181
we're gonna go universal even though the first two weeks
选择 universal，尽管前两周
362
00:17:30,183 --> 00:17:33,151
we're going to be focusing on iPhone only. In the third week
我们只会专注在 iPhone 上
363
00:17:33,153 --> 00:17:37,688
we'll expand our calculator to work on an iPad as well. Here,
在第三周，我们会让计算器在 iPad 上也正常地跑起来
364
00:17:37,690 --> 00:17:39,657
we're not going to be using databases yet, that will be
目前我们还不需要使用数据库
365
00:17:39,659 --> 00:17:43,661
about week six and we will be talking about testing later in
第六周我们会讨论测试
366
00:17:43,663 --> 00:17:45,563
the quarter. Probably in a Friday section again, but
也许在周五的课程中
367
00:17:45,565 --> 00:17:48,733
we're not doing it now so you can leave these unchecked.
我们现在不会处理这些，所以这些不需要勾选
368
00:17:48,735 --> 00:17:49,767
All right, so now I hit Next, and
点 Next
369
00:17:49,769 --> 00:17:53,037
it says where do you wanna put this project? I'm gonna put
它问你想把项目放在哪里
370
00:17:53,039 --> 00:17:56,808
it in my home directory, in a folder called Developer, and
我把它放到 ~/Developer 中
371
00:17:56,810 --> 00:17:59,444
I highly recommend you do the same, okay.
我也建议你们这样做
372
00:17:59,446 --> 00:18:02,180
Home Directory Developer, so all your apps will start
~/Developer，你们所有的 App 都放到这里
373
00:18:02,182 --> 00:18:05,750
piling up in here. Here's the source control thing I was
关于源码管理
374
00:18:05,752 --> 00:18:07,785
talking about, we're not gonna do this at the beginning, so
我们一开始先不管
375
00:18:07,787 --> 00:18:10,521
we're gonna leave this unchecked. All right. So
所以先不勾选
376
00:18:10,523 --> 00:18:13,324
we hit create, and it creates our first app. Now, it's
点 create，它就创建了我们的第一个 App
377
00:18:13,326 --> 00:18:16,961
actually created these six files, over here on the side.
它实际上创建了这 6 个文件，在这侧边
378
00:18:16,963 --> 00:18:17,762
And over the course of the quarter,
在课程期间
379
00:18:17,764 --> 00:18:20,498
I'll show you what all six of these are about. Today,
我会告诉你们这 6 个文件都是做什么的
380
00:18:20,500 --> 00:18:23,768
we're only gonna focus on two of them.
今天我们只会关注这两个
381
00:18:24,871 --> 00:18:27,772
How many of you have used Xcode before, for any class or
你们有谁用过 Xcode？
382
00:18:27,774 --> 00:18:31,509
anything? Okay, so about a third of you.
好，大概 1/3
383
00:18:31,511 --> 00:18:34,178
So let me explain a little bit about Xcode's UI,
我先介绍一下 Xcode 的 UI
384
00:18:34,180 --> 00:18:36,781
what it looks like. You see this area on the left,
左边这里
385
00:18:36,783 --> 00:18:40,051
this blue area? That's called the Navigator and
蓝色的区域，它是 Navigator(导航器)
386
00:18:40,053 --> 00:18:43,554
it's basically for navigating your project.
它用来导航你的项目
387
00:18:43,556 --> 00:18:44,755
And you can do it in different ways.
通过几种不同的方式
388
00:18:44,757 --> 00:18:48,459
This is the Project Navigator that we see right here, and
现在这个是项目导航
389
00:18:48,461 --> 00:18:50,595
it's basically showing you your files.
它用来显示项目的文件
390
00:18:50,597 --> 00:18:52,029
You can arrange them in folders and stuff, but
你可以通过文件夹来重新组织它们
391
00:18:52,031 --> 00:18:55,166
just basically the files in your app. But you can navigate
但只是导航 App 中的文件
392
00:18:55,168 --> 00:18:58,669
by searching, okay, you can type some search text in here,
但是你可以通过搜索来查找 App 文件中的内容
393
00:18:58,671 --> 00:19:01,472
search for it in your app. You can navigate all your
如果你在 debug 的时候
394
00:19:01,474 --> 00:19:04,675
breakpoints if you're debugging. You can go back and
可以在这里查看所有断点
395
00:19:04,677 --> 00:19:07,345
look at all your old builds to see any errors or
查看之前编译版本的错误或警告
396
00:19:07,347 --> 00:19:11,149
warnings you have, okay, even if you fixed it you go back,
即使你已经修复了它们并返回了
397
00:19:11,151 --> 00:19:13,484
and look at them. So the navigator is kind
Navigator 就像是用来关注
398
00:19:13,486 --> 00:19:16,521
of how you keep track of what's going on in your app.
你的 App 到底发生了什么事情的地方
399
00:19:16,523 --> 00:19:19,457
On the right hand side here we have the utilities area,
在右手边，有 Utilities(工具) 区
400
00:19:19,459 --> 00:19:22,426
which is actually two windows, see it's split top and
有两个窗口，分成上下两部分
401
00:19:22,428 --> 00:19:26,230
bottom here. The top part is essentially an inspector,
上部是 Inspector(监视器)
402
00:19:26,232 --> 00:19:29,800
it's going to let you analyze and change attributes of
你可以通过它看到或改变
403
00:19:29,802 --> 00:19:33,004
whatever's selected in this main window. Right now we
在主窗口选中的东西的属性
404
00:19:33,006 --> 00:19:35,673
don't have anything selected, so it's not showing anything.
现在没有选中任何东西，所以没显示任何东西
405
00:19:35,675 --> 00:19:38,676
And this bottom is essentially like a palette. Okay,
这下面的部分就像一个调色板
406
00:19:38,678 --> 00:19:41,979
you're gonna be an artist building your app, okay, and
在写应用的时候，你就是一个艺术家
407
00:19:41,981 --> 00:19:45,983
you're gonna need things like buttons and web views,
因为你需要类似于 button 或 web view 之类的东西
408
00:19:45,985 --> 00:19:47,818
and things like that, to build your app, and
用来搭建你的应用
409
00:19:47,820 --> 00:19:48,953
you're gonna be finding them all,
你会在这里找到它们
410
00:19:48,955 --> 00:19:51,122
and pulling them all out of here. So it's your palette,
然后可以从这里把它们拖出来，所以这就是你的调色板
411
00:19:51,124 --> 00:19:54,825
your artist palette, as you build things. Okay? You can
你的艺术调色板，用来创造东西
412
00:19:54,827 --> 00:19:57,361
show and hide these two side panels with these buttons,
你可以通过这些按扭显示或者隐藏侧面的面板
413
00:19:57,363 --> 00:20:00,831
up here. I will tend to not do command keys, except for
我尽量不使用快捷键，除了复制粘贴
414
00:20:00,833 --> 00:20:03,801
like copy and paste, so that you can see what's going on.
所以你们就可以知道我到底做了哪些事情
415
00:20:03,803 --> 00:20:06,204
But there are tons of command keys in Xcode, and
但是 Xcode 中有大量的快捷键
416
00:20:06,206 --> 00:20:10,441
if you go To Xcode preferences and look under
在 Xcode 的设置界面
417
00:20:10,443 --> 00:20:12,610
key bindings right here you can see all of them and
你可以发现有大量大量的快捷键
418
00:20:12,612 --> 00:20:15,680
there's tons and tons and tons and you can even change them.
你也可以对它们进行定制
419
00:20:15,682 --> 00:20:17,348
Of course if you don't like them but
如果你不喜欢它们也没关系
420
00:20:17,350 --> 00:20:18,849
it has a lot of commands. All right, so
但是它有大量的快捷键
421
00:20:18,851 --> 00:20:21,886
I'll try to avoid using those command keys. So you can hide
我尽量不使用快捷键
422
00:20:21,888 --> 00:20:25,756
those with these things so you have hidden both sides, right.
可以使用按扭来做这些事情
423
00:20:25,758 --> 00:20:28,426
So you can kind of manage your screen real estate.
你可以管理屏幕的分辨率
424
00:20:28,428 --> 00:20:31,662
Now I have a very low-resolution screen here, so
我电脑的分辨率非常低
425
00:20:31,664 --> 00:20:34,732
I have to manage my real estate quite efficiently.
所以为了高效我需要改变自己的分辨率
426
00:20:34,734 --> 00:20:36,567
If you have a higher resolution screen,
如果你的分辨率很高
427
00:20:36,569 --> 00:20:39,837
then you would obviously not be doing as much hiding and
你就不需要把这些东西给隐藏起来了
428
00:20:39,839 --> 00:20:44,108
showing of these things. So if we look at the navigator,
现在我们看 Navigator
429
00:20:44,110 --> 00:20:44,775
what's selected right now?
当前选中的是什么？
430
00:20:44,777 --> 00:20:48,980
It's the project itself at the very top level, this blue bar.
是最顶层的项目本身
431
00:20:48,982 --> 00:20:49,680
This selecting the project.
它选中了项目
432
00:20:49,682 --> 00:20:53,217
So we're actually seeing the project, the kind
所以在主窗口
433
00:20:53,219 --> 00:20:55,820
of settings of the project, in the main window here.
我们可以看到这个项目的设置
434
00:20:55,822 --> 00:20:59,624
This main window. Here are some of them here, right?
这个主窗口，这里有一些设置
435
00:20:59,626 --> 00:21:01,325
Some of these we set on that first page,
第一页有一些可以设置的
436
00:21:01,327 --> 00:21:05,029
like the bundle identifier and whether it was universal or
例如 Bundle Identifier（包的 ID）
437
00:21:05,031 --> 00:21:07,898
iPad and iPhone, etc. But there's plenty more
是通用的还是只为了 iPhone 或 iPad 而造
438
00:21:07,900 --> 00:21:10,868
settings over here. We'll get to most of those settings as
这里还有许多其它设置信息
439
00:21:10,870 --> 00:21:14,372
the quarter goes by. The only setting that's important for
随着课程的进行，我们会逐渐了解这些设置
440
00:21:14,374 --> 00:21:16,540
you to know now, is this team setting.
现在需要知道的设置信息是这个 team
441
00:21:16,542 --> 00:21:19,477
See here where it says team none? You're gonna wanna be
现在上面显示的是 none
442
00:21:19,479 --> 00:21:24,782
able to write your app, and have it run on a device. Okay.
你想让你写的 App 运行在真实的设备上
443
00:21:24,784 --> 00:21:26,817
It has a simulator, which I'm gonna use today.
我们今天会使用模拟器
444
00:21:26,819 --> 00:21:29,253
But you also wanna be able to run on a device. And
但是你想让它运行在真实的设备上
445
00:21:29,255 --> 00:21:33,124
to do that you need to register an Apple ID.
为了这样，我们需要注册一个 Apple ID
446
00:21:33,126 --> 00:21:36,060
So here I already have mine, this CS193p Instructor, but
我已经注册好了
447
00:21:36,062 --> 00:21:39,630
you're going to go down here to add an account, and
不过你需要在这下面添加一个账号
448
00:21:39,632 --> 00:21:42,466
you're going to give an Apple ID and password. Any Apple ID
填入 Apple ID 和密码
449
00:21:42,468 --> 00:21:45,736
will do, you don't have to join any program or anything,
任意一个 Apple ID 都可以，不需要加入什么开发者计划之类的
450
00:21:45,738 --> 00:21:48,372
just any Apple ID will work here. And
普通的 Apple ID 就可以
451
00:21:48,374 --> 00:21:49,874
you'll put the ID and password in, and
填入 ID 和密码
452
00:21:49,876 --> 00:21:51,676
then you're going to select it here. And
选这里
453
00:21:51,678 --> 00:21:56,280
then it's going to appear here, like this. Okay? Now,
它会在这里出现
454
00:21:56,282 --> 00:21:59,617
when you have a team selected now you can plug a device
当 team 有选择的东西以后，你就可以插上一个设备
455
00:21:59,619 --> 00:22:02,720
in and you're gonna get this warning here, no provisioning
会有一个没有证书的警告
456
00:22:02,722 --> 00:22:07,158
profiles found. And you just click fix issue right there.
点这里的 fix issue
457
00:22:07,160 --> 00:22:08,926
You have to be connected to the network at the time,
这时你需要联网
458
00:22:08,928 --> 00:22:11,829
all right? Fix issue and it'll fix that.
它会修复这个问题
459
00:22:11,831 --> 00:22:14,198
It'll basically get the ID of your device,
它会获取你设备的 ID
460
00:22:14,200 --> 00:22:18,436
register it with you as the developer and off you go.
注册成为开发者，然后就可以了
461
00:22:18,438 --> 00:22:21,672
Okay? So you'll need to do that. You only really need to
你只需要在想把 App 运行在真实设备的时候
462
00:22:21,674 --> 00:22:23,808
do that when it comes to running on a device.
才需要解决这个问题
463
00:22:23,810 --> 00:22:25,476
When we're running in a simulator you're not gonna
当在模拟器上运行的时候
464
00:22:25,478 --> 00:22:28,913
need to do that, but you might as well get this started now.
就不用这么做
465
00:22:29,048 --> 00:22:32,316
Okay? Now what about these other files over here in the
Navigator 中的其它这些文件
466
00:22:32,318 --> 00:22:35,453
navigator that it made these 6 files. Well like I said, were
都有什么作用呢？
467
00:22:35,455 --> 00:22:37,922
not going to talk about all of them. This one for example,
我不会对它们每一个都进行详细讲解
468
00:22:37,924 --> 00:22:42,093
assets.xcassetts. That's all your media assets. So that's
例如 assets.xcassets 是存放媒体文件的地方
469
00:22:42,095 --> 00:22:46,997
images, sounds, icons, things like that. Here for example is
图片，声音和图标之类的东西
470
00:22:46,999 --> 00:22:47,965
the app icon which I haven't set so
例如这里的应用图标
471
00:22:47,967 --> 00:22:51,635
all of these are all blank. So we're not really gonna talk
我还没有设置，所以这些都是空白的
472
00:22:51,637 --> 00:22:53,738
about that today but we'll eventually talk about it.
我今天不会介绍，但总有一天会介绍的
473
00:22:53,740 --> 00:22:56,841
And in fact not only am I not gonna talk about
实际上今天我不但不会介绍这个 xcassets 文件
474
00:22:56,843 --> 00:22:59,877
this xcassets thing right here, but I'm also not gonna
同样我也不会介绍
475
00:22:59,879 --> 00:23:02,813
talk about this app delegate or the launch screen or
AppDelegate 和 LaunchScreen 还有
476
00:23:02,815 --> 00:23:06,350
the info.plist. Okay, so I'm gonna select all those and
info.plist 文件
477
00:23:06,352 --> 00:23:10,254
right-click on them and choose new group from selection and
我选中它们
478
00:23:10,256 --> 00:23:13,424
put them all in a folder. Okay, which I'm gonna call
然后右键为它们新建一个组
479
00:23:13,426 --> 00:23:17,261
supporting files. Because that's what they are really,
起名为 Supporting files
480
00:23:17,263 --> 00:23:19,330
they're kind of files to support my app.
因为它们对我 App 起的就是支持作用
481
00:23:19,332 --> 00:23:20,264
You see they're still there,
你看，它们还在这里
482
00:23:20,266 --> 00:23:21,799
I just kind of got them out of the way so
我只是把它们清理一下
483
00:23:21,801 --> 00:23:23,834
we can focus on these two files
这样我就可以关注这两个文件
484
00:23:23,836 --> 00:23:27,972
which is the most important thing to our demo today. Okay?
它俩是今天 demo 中最重要的部分
485
00:23:27,974 --> 00:23:31,409
Now what are these two files? Now is where I have to talk
这俩文件是干什么的？
486
00:23:31,411 --> 00:23:34,812
about this MVC thing, okay? So MVC stands for
现在我就得讲讲 MVC 了
487
00:23:34,814 --> 00:23:39,917
Model View Controller, okay? Model View Controller is a way
MVC 代表 Model(模型) View(视图) Controller(控制器)
488
00:23:39,919 --> 00:23:43,354
of kind of dividing up all the classes in our object orient
MVC 是一种把我们面向对象 App 中的类分成几种不同组的方式
489
00:23:43,356 --> 00:23:46,457
app into three different groups, the model group,
Model 组
490
00:23:46,459 --> 00:23:48,826
the view group, and the controller group.
View 组和 Controller 组
491
00:23:48,828 --> 00:23:52,163
Okay, what are those three groups? The model group is
这三个组都是什么？Model 组是
492
00:23:52,165 --> 00:23:55,900
what our program does It's UI independent.
关于我们的 App 是做什么的，它与 UI 是独立的
493
00:23:55,902 --> 00:23:58,736
So for a calculator it's going to be all the calculating.
对于计算器来说，它是关于计算的
494
00:23:58,738 --> 00:24:01,172
The things that actually does the calculations, right?
它实际做的事情就是计算，对吧？
495
00:24:01,174 --> 00:24:04,275
That's UI independent, that's going to be our model, okay?
它是 UI 独立的，它就是我们的 Model
496
00:24:04,277 --> 00:24:08,012
The view is the user interface that the user interacts with.
View 就是用户直接接触的 UI 界面
497
00:24:08,014 --> 00:24:11,315
So for the calculator it's the buttons and the display and
对于计算器来说就是按扭还有显示之类的东西
498
00:24:11,317 --> 00:24:14,051
all that stuff. That is the view. Okay, usually that's
这就是 View
499
00:24:14,053 --> 00:24:17,254
made of generic user interface elements like buttons and
通常它是由基本的例如按扭之类的 UI 元素组成
500
00:24:17,256 --> 00:24:20,391
things like that. And then there's the controller,
接着就是 Controller
501
00:24:20,393 --> 00:24:23,461
the controller is the glue between the model and
controller 是 model 与 view 之间的粘合剂
502
00:24:23,463 --> 00:24:26,130
the view. Okay, it's the thing that listens to what's
它会监听UI发生了些什么事情
503
00:24:26,132 --> 00:24:30,267
happening in the UI, makes decisions, updates the model,
做出决定，传达给 model，让 model 更新
504
00:24:30,269 --> 00:24:30,901
something changes in the model,
model 里的一些东西就会发生改变
505
00:24:30,903 --> 00:24:34,438
maybe it changes the UI. Okay, back and forth is really where
可能会改变UI，好的，说来说去
506
00:24:34,440 --> 00:24:37,608
the interface, the logic of our entire app really
我们 app 的整套逻辑生存在 controller 里
507
00:24:37,610 --> 00:24:41,879
lives in our controller, okay? So, this file right here,
okay? 所以，这有一个文件
508
00:24:41,881 --> 00:24:45,950
ViewController.swift, that is our controller, okay?
ViewController.swift，这就是我们的 controller，okay?
509
00:24:45,952 --> 00:24:51,355
Our app only has one MVC, okay? Which is the calculator,
我们的app仅有一个 MVC，okay? 就是这个计算器
510
00:24:51,357 --> 00:24:54,024
MVC and this is it's controller, okay,
MVC和它是这个app的 controller，okay?
511
00:24:54,026 --> 00:24:59,296
the C of MVC. Now, here is your first look at Swift. E,
MVC中的 C，现在，这里是你看到的第一个 swift 程序
512
00:24:59,298 --> 00:25:00,598
we're gonna, I'm gonna explain this little,
我等下将会解释一下这个东西
513
00:25:00,600 --> 00:25:04,168
real briefly. You can see that Xcode has thrown in a couple
非常简单，你可以看到 Xcode 里有一些方法
514
00:25:04,170 --> 00:25:07,571
of methods for me. Everyone knows what a method is.
大家都知道方法是什么
515
00:25:07,573 --> 00:25:09,874
They're so exciting that I'm gonna delete them, okay?
我要删除掉它们，它们显得非常 exciting! okay?
516
00:25:09,876 --> 00:25:12,910
That's because I, I don't wanna distract you with a lot
因为我不想你们被这些代码带走注意力
517
00:25:12,912 --> 00:25:15,513
of random code, so we're gonna keep down just to the minimal
所以我们只保留我们要用的代码
518
00:25:15,515 --> 00:25:16,547
code we're gonna use. We don't,
所以我们只保留我们要用的代码
519
00:25:16,549 --> 00:25:19,783
we will be using those methods later in the course.
我们在后续课程中会用到这些方法
520
00:25:19,785 --> 00:25:21,318
Those are part of what's called the view-controller
这些就是所说的 view-controller 的一部分
521
00:25:21,320 --> 00:25:25,189
lifecycle. But we don't need it for our calculator app. So
但我们的计算器里不需要它
522
00:25:25,191 --> 00:25:26,357
let's look at what we have left here.
所以我们看看留在这里的代码
523
00:25:26,359 --> 00:25:30,461
This import is kind of like an include in other languages or
这个 import 就像其它语言里的 include 一样
524
00:25:30,463 --> 00:25:33,864
import in other languages. But this is not a file,
或是其它语言里的 import，但这不是一个文件
525
00:25:33,866 --> 00:25:37,368
this is a module. And in Swift, you can group a whole
它是一个模块，在 swift 中，你可以把一堆类打包在一起
526
00:25:37,370 --> 00:25:42,306
bunch of classes together. And that's called a module. And
这就可以叫做一个模块
527
00:25:42,308 --> 00:25:45,976
when you import a module all those classes will be visible,
当你导入一个模块，里面所有的类都对你可见
528
00:25:45,978 --> 00:25:49,947
if they're public classes, to whatever is using it. So here,
当然如果它们是 public 类的话，不管谁用都如此
529
00:25:49,949 --> 00:25:53,751
UI kit has all these interface things, buttons, text fields,
所以这个 UIkit 里有所有的的界面，按钮，文本框
530
00:25:53,753 --> 00:25:56,620
all that stuff is in there. And so since we're building
所有的东西都在这个模块里，因为我们要做一个 UI app
531
00:25:56,622 --> 00:25:59,924
a UI app here, a calculator, we're gonna import UIkit, and
一个计算器，我们我们要导入 UIkit
532
00:25:59,926 --> 00:26:02,059
you're almost always gonna import UIkit,
你几乎总是需要导入这个模块
533
00:26:02,061 --> 00:26:04,828
okay? Now in our model, where it's UI independent,
现在在我们的 model 中，UI是独立的
534
00:26:04,830 --> 00:26:07,298
we're gonna probably be importing foundation.
我们也许需要导入 foundation 框架
535
00:26:07,300 --> 00:26:09,967
Foundation is that core services thing, okay?
Foundation 是一个核心框架，okay？
536
00:26:09,969 --> 00:26:11,268
Cuz we might be doing networking and
因为我们可能需要网络编程
537
00:26:11,270 --> 00:26:13,370
databasing in our model, but we're not doing buttons and
或者使用数据库，但我们不需要做一些按钮之类的东西
538
00:26:13,372 --> 00:26:17,374
stuff. So those are the two main things you import, okay.
所以这两个模块你需要导入
539
00:26:17,376 --> 00:26:21,078
Here is the definition, declaration really,
这里是 swift 里对一个类进行定义时看起来的样子
540
00:26:21,080 --> 00:26:24,248
of a class in Swift is what it looks like.
这里是 swift 里对一个类进行定义时看起来的样子
541
00:26:24,250 --> 00:26:28,052
You've got the class keyword. This is the name of the class,
你需要用到 class 关键字，这是这个类的名字
542
00:26:28,054 --> 00:26:30,020
ViewController. Now this is a pretty bad name,
ViewController，一个很差劲的名字
543
00:26:30,022 --> 00:26:33,190
okay, because its very generic, ViewController
因为 ViewController 这个名字不够具体
544
00:26:33,192 --> 00:26:36,160
probably be better called calculator controller, or
我们最好叫它计算器 controller
545
00:26:36,162 --> 00:26:37,394
calculator view controller.
或者计算器 view controller 之类的名字
546
00:26:37,396 --> 00:26:39,363
I'm not gonna show you how to rename that now.
我现在不会教你们怎么重命名
547
00:26:39,365 --> 00:26:42,766
But I will show you next week. But this is the name of our
在下周我会展示给你看，这是我们 controller 类的名字
548
00:26:42,768 --> 00:26:46,937
controller class. This colon UIViewController, means that
这个 UIViewController 意味着
549
00:26:46,939 --> 00:26:50,808
UIViewController is the class our controller inherits from.
我们的类继承于 UIViewController 类
550
00:26:50,810 --> 00:26:53,277
This is object oriented program, we have inheritance.
这是个面向对象程序，需要继承机制
551
00:26:53,279 --> 00:26:56,914
This is the inheritance. Single inheritance in Swift.
这就是一个 swift 里单继承的例子
552
00:26:56,916 --> 00:27:01,485
All controllers, all MVC controllers must inherit from
所有的 controller，所有的 MVC controller 都必须
553
00:27:01,487 --> 00:27:04,521
UIViewController either directly or indirectly from
直接或间接地继承于 UIViewController
554
00:27:04,523 --> 00:27:08,125
UIViewController. Okay, then we have a curly brace here,
Okay，这里我们有了大括号
555
00:27:08,127 --> 00:27:11,695
inside those curly braces goes all of our properties and
所有的属性和方法写在这个括号里
556
00:27:11,697 --> 00:27:14,131
methods. Properties are like instance variables.
比方说一些变量
557
00:27:14,133 --> 00:27:15,299
Everyone knows what an instance variable is,
每个人都该知道什么是实例变量
558
00:27:15,301 --> 00:27:18,636
right? So our property, we call them properties in Swift.
在 swift 中我们称 property 是属性
559
00:27:18,638 --> 00:27:21,438
They're very powerful in Swift, the instance variables.
实例变量在 swift 里面非常有用
560
00:27:21,440 --> 00:27:23,007
They can have behavior associated with them and
它们可以被一些有关联的行为改变
561
00:27:23,009 --> 00:27:26,543
things like that. But all that goes inside these curly
但所有的一切都发生在这对大括号里
562
00:27:26,545 --> 00:27:30,247
braces, okay? So that's your intro to Swift.
好吗？ 所以这就是对 swift 的简短介绍
563
00:27:30,249 --> 00:27:33,350
What about this other file over here? Main.storyboard,
这个 Main.storyboard 文件又是怎么回事？
564
00:27:33,352 --> 00:27:39,089
what's that? That's the V for view of our MVC. That's
它是什么呢？就是 MVC 里面的 V
565
00:27:39,091 --> 00:27:42,559
the graphical representation of our calculator.
它代表着我们的计算器的图形界面
566
00:27:42,561 --> 00:27:44,962
So let's click on that, and see what it looks like.
所以我们点它一下， 看看会发生什么
567
00:27:44,964 --> 00:27:49,833
Right now, it's just a big square. Big empty square here.
现在，它只是一个大方块，大的空方块
568
00:27:49,835 --> 00:27:51,935
And I can zoom in and out, so I'll zoom to 50%,
我可以放大和缩小，那我就缩小50%
569
00:27:51,937 --> 00:27:55,572
see? Here's our UI, now, it's kinda interesting,
看，这就是我们的UI, 有点意思对不对
570
00:27:55,574 --> 00:28:02,946
this UI is square, okay? How many iOS products are square?
这个UI是方形的，okay? 有多少iOS程序是方形的？
571
00:28:02,948 --> 00:28:06,717
Zero, right? None of them are, they're all rectangular, okay?
零个，记住了吗？没有一个是方形的，它们都是长方形的
572
00:28:06,719 --> 00:28:09,520
So they're either landscape or portrait, you know, iPads,
而且他们不是横屏的就是竖屏的，你知道的
573
00:28:09,522 --> 00:28:11,388
whatever. None of them are square.
没有一个是方形的
574
00:28:11,390 --> 00:28:16,093
So how are we building our UI in a square UI? Well we're
所以如何在这个方形UI中建立我们自己的UI?
575
00:28:16,095 --> 00:28:19,263
doing that to remind us that we want to build our UI so
时刻谨记，我们要建立自己的UI
576
00:28:19,265 --> 00:28:23,901
that it stretches and expands and moves things around so
它能够伸缩自如，也得能移动UI里的东西
577
00:28:23,903 --> 00:28:26,470
that it will fit in any shape. Okay,
并且能够适应不同的设备
578
00:28:26,472 --> 00:28:29,039
so we're gonna build one UI, it's gonna work on iPad,
所以我们要做一个可以在各种iPad
579
00:28:29,041 --> 00:28:32,209
iPhone, tall iPhones, short iPhones, high resolution ones,
iPhone，长iPhone，短iPhone，高分辨率设备
580
00:28:32,211 --> 00:28:35,713
low resolution, all of them from this one UI. And this is
低分辨率设备，所有的设备只需要一个UI
581
00:28:35,715 --> 00:28:39,516
square to remind us that if this were vertical rectangle,
这个方形提醒我们 如果这是个垂直长方形
582
00:28:39,518 --> 00:28:42,186
probably our UI would look great in portrait, but
或许它更适合竖屏使用
583
00:28:42,188 --> 00:28:42,386
good in landscape. This way, square, it's constantly
这样，对于横屏使用来讲
584
00:28:42,388 --> 00:28:45,089
maybe not so
或许就不那么合适
585
00:28:45,091 --> 00:28:47,591
reminding us that we have to build this flexible UI.
不要忘了我们要做一个足够灵活的UI
586
00:28:47,593 --> 00:28:49,059
Now today, I'm not gonna do that.
今天我并不打算做这件事
587
00:28:49,061 --> 00:28:52,463
I'm gonna build the UI all up in the upper left corner right
我会在这个左上角上建立我们的UI
588
00:28:52,465 --> 00:28:54,531
here so that it looks good in any, or
或许好看
589
00:28:54,533 --> 00:28:58,569
not looks good, but at least shows up in any shape. But
或许不好看，但至少适用于任何设备
590
00:28:58,571 --> 00:29:01,472
on Wednesday, we'll put in the flexibility to make it,
星期三的时候，我们教你们一些方法
00:29:01,474 --> 00:29:06,577
do what it needs to do, okay. So, how do we build this UI?
来给它注入更多的灵活性。所以，我们如何建造这个UI?
592
00:29:06,579 --> 00:29:09,747
We build our entire UI graphically. Okay,
我们用图形拖拽的方式，Okay?
593
00:29:09,749 --> 00:29:12,116
with the mouse. Okay, we do not write code,
用鼠标，我们不需要写任何代码
594
00:29:12,118 --> 00:29:16,420
to say put button here, to put text field there. We just
把按钮放在这里，把文本框放在那里
595
00:29:16,422 --> 00:29:20,557
build it all graphically, and wire it up with our mouse. And
我们只需要用图形的方式来完成，用鼠标做这事
596
00:29:20,559 --> 00:29:22,559
so we're just going to dive right into doing that.
现在我们马上就开始做这个UI
597
00:29:22,561 --> 00:29:26,263
I'm building a calculator. A calculator needs some buttons.
我要做一个计算器，一个计算器需要一些按键
598
00:29:26,265 --> 00:29:27,464
So let's start with a button.
那么我们就从按键开始
599
00:29:27,466 --> 00:29:30,834
I told you that in this utilities window at the bottom
我告诉过你们在 utilities 窗口
600
00:29:30,836 --> 00:29:34,037
there's the palette of things you as an artist, and now we
有一个“调色板”提供给你这个“艺术家”
601
00:29:34,039 --> 00:29:37,975
are UI artists here, are going to build our UI out of. And
现在我们就是UI设计艺术家，将要创造我们的UI
602
00:29:37,977 --> 00:29:41,645
you can see there is whoops. Get that back out of the way.
你可以看见，whoops，把它放到后面去
603
00:29:41,647 --> 00:29:44,848
There we go. Lots and lots of things that we can build our
好了，这里面有很多很多东西我们可以拿来
604
00:29:44,850 --> 00:29:47,918
UI out of here, and we'll talk about actually most of these
构造我们的UI,接下面的几周这些东西
605
00:29:47,920 --> 00:29:50,654
in the ten weeks we have, but we're gonna start about
大多我们都会介绍，但从大概这个四分之一
606
00:29:50,656 --> 00:29:54,258
a quarter of the way down with this one right here button.
的位置这的这个按钮开始
607
00:29:54,260 --> 00:29:56,026
And I'm just gonna pick this up.
我将会点击它
608
00:29:56,028 --> 00:29:59,496
And drag it out, it's my UI. Now when I do that,
把它拖出来，这就是我的UI，当我做这事的时候
609
00:29:59,498 --> 00:30:02,566
notice that these blue lines appear and disappear.
注意下这些出现又消失蓝色的线条
610
00:30:02,568 --> 00:30:06,603
The blue lines help you put something in a theoretical or
这些蓝色线条帮你把东西放在合适的地方
611
00:30:06,605 --> 00:30:10,774
conceptual place. Like this would be putting the button
就像这个给我参考，让我把这个按钮放在
612
00:30:10,776 --> 00:30:13,477
in the conceptual center of my UI. So
我UI框架的中心
613
00:30:13,479 --> 00:30:16,079
if I am portrait it's going to be centered in portrait.
如果我竖屏，它会处于竖屏的中心位置
614
00:30:16,081 --> 00:30:18,882
If I go to landscape it will move over and be in landscape.
如果我横屏，它会移动到横屏的中心位置去
615
00:30:18,884 --> 00:30:22,853
Do you understand what I'm saying? These blue lines allow
你明白我在说什么吗？这些蓝色线条
616
00:30:22,855 --> 00:30:25,088
us to put things in various places and
让我们能把UI元素放在很多地方
617
00:30:25,090 --> 00:30:26,423
this is a big part of how we're going to
对于如何做出一个灵活的UI来说，这些
618
00:30:26,425 --> 00:30:29,159
make this flexible UI. But since I told you I'm not gonna
蓝色线条很关键，不过我已经说了周三再来展示
619
00:30:29,161 --> 00:30:31,094
show you that until Wednesday, we're not gonna do that.
所以今天我不会管它
620
00:30:31,096 --> 00:30:33,764
We're not gonna use the blue lines, okay. But you'll see me
我们不使用这些蓝色线条，okay，等到周三
621
00:30:33,766 --> 00:30:35,766
using the blue lines on Wednesday quite a bit and
我才会告诉你们怎么使用这些线条
622
00:30:35,768 --> 00:30:37,234
you'll want to always use the blue lines.
然后你们就离不开它了
623
00:30:37,236 --> 00:30:41,071
The blue lines are super important to building this
对于做一个足够灵活的UI来讲
624
00:30:41,073 --> 00:30:42,139
flexible adaptable UI.
这些蓝色线条特别重要
625
00:30:42,141 --> 00:30:44,608
All right, so we have our button right here, now we
好了，所有现在我们的按键摆在那了
626
00:30:44,610 --> 00:30:47,711
don't want it to say button on there. Okay, we want it to be
现在我不想要这个空白按键呆在那，我想要
627
00:30:47,713 --> 00:30:50,747
one of the numbers this is gonna be part of our keypad.
它变成我们的一个数字按键
628
00:30:50,749 --> 00:30:53,016
So I'm gonna make this be my five button. And
所以我要把它变成“5”这个按键
629
00:30:53,018 --> 00:30:55,552
to change the text you can just double click on it and
要改变它的文本信息你只需要双击它
630
00:30:55,554 --> 00:30:58,989
change it. So I'm gonna make it 5. You notice it also has
然后改成你要的文本，所以我把它改成“5”，
631
00:30:58,991 --> 00:31:01,825
these little handles around the edge. You can use those to
你可以看见这些边缘上的小框框，你可以用它改变按钮的大小
632
00:31:01,827 --> 00:31:05,229
resize it to whatever you want. So this is computer
这是一门计算机科学课
633
00:31:05,231 --> 00:31:09,466
science class, so we'll make it be 64 by 64, okay? Although
所以我们把它做成64*64大小的，okay?
634
00:31:09,468 --> 00:31:12,636
it really doesn't matter what size I make this, because when
不过我把它做成什么大小真的不重要
635
00:31:12,638 --> 00:31:15,072
it starts being flexible it's gonna start you know,
因为面对不同的环境的时，一个灵活的UI
636
00:31:15,074 --> 00:31:18,141
resizing it to fit depending on what's the environment, but
可以让这些按钮自动变换到合适的尺寸
637
00:31:18,143 --> 00:31:21,345
anyway we'll do that. Now other things I wanna change
不过我还是示范下，现在，这个按钮还有一些需要改变的地方
638
00:31:21,347 --> 00:31:23,480
about this button I don't do directly.
但我不直接做
639
00:31:23,482 --> 00:31:27,517
I need to use this top half of the utilities window here,
我需要用到 utilities 窗口的上半部分
640
00:31:27,519 --> 00:31:30,721
which is the Inspector. Okay, now there's different kinds of
这是一个检测窗口，Okay，现在这有一些
641
00:31:30,723 --> 00:31:33,557
inspectors along the top you'll see here. What you,
不同的种类的检测
642
00:31:33,559 --> 00:31:35,926
what's showing now is the Attributes Inspector.
现在你看到的是属性监测
643
00:31:35,928 --> 00:31:39,129
That, that is the attributes of whatever is selected.
无论我选中了什么属性都会展示在上边
644
00:31:39,131 --> 00:31:41,899
Here is the size inspector. So if I click that, for
这里时一个尺寸监测，所以如果我点击它
645
00:31:41,901 --> 00:31:45,269
example here's my 64 by 64 and I can edit it here as well.
这里就是我的64*64，我们同样也能在这里改变尺寸
646
00:31:45,271 --> 00:31:50,774
I can say 200 by 64, see how this got wide, all right?
我可以改成200*64，看这个怎么变得更宽，all right?
647
00:31:50,776 --> 00:31:53,443
We can go back to 64.
我们也可以改回64
648
00:31:53,445 --> 00:31:55,979
Okay. I'm going to go back to the app.
好了，回到我们的app
649
00:31:55,981 --> 00:31:58,415
And we will talk about these other ones the identity and
我们将会在之后再介绍身份监测，这之类些东西
650
00:31:58,417 --> 00:32:01,752
Spector later. But lets go back here to attributes and
回到我们的属性界面
651
00:32:01,754 --> 00:32:04,154
inspector this is actually object oriented. So
这是面向对象的，所以
652
00:32:04,156 --> 00:32:06,623
here I can set the attributes of a button because that's
所以我能设置这个按钮的属性
653
00:32:06,625 --> 00:32:10,027
what's selected here. And also I can set the attributes of
同样我也能设置这个 controls 属性
654
00:32:10,029 --> 00:32:13,830
a control, which is buttons super class, and
它是按键的父类
655
00:32:13,832 --> 00:32:17,634
then attributes of view, which is controls super class.
再设置 view 里面的属性，它是 controls 的父类
656
00:32:17,636 --> 00:32:20,537
So this goes right up the hierarchy of the inherit
所以它们遵循着继承的体系，一个类继承于另一个
657
00:32:20,539 --> 00:32:23,640
hierarchy, rather, and lets me set various things.
现在让我设置一些东西
658
00:32:23,642 --> 00:32:26,543
For example, I want this five to be bigger, so
比如，我想要这个“5”更大一点
659
00:32:26,545 --> 00:32:30,447
I look here in the buttons attributes and I see font,
所以我看看这个按钮的属性，我看到了“字体”
660
00:32:30,449 --> 00:32:33,850
system font, 15 point. I'm gonna click this and
系统字体，15号，我点击它一下
661
00:32:33,852 --> 00:32:37,154
change this to be 30 point system font. Okay,
把它变成30号的字体，Okay
662
00:32:37,156 --> 00:32:41,291
that looks a lot better. And if I go back and look at this
看起来好多了，如果我再回去看看这个计算器
663
00:32:41,293 --> 00:32:43,961
calculator, see how some of the buttons have a background,
看如何使这个按钮有不同颜色的背景
664
00:32:43,963 --> 00:32:46,763
like grey or orange? I want that too so I'm gonna set
比如绿色或者橘色，所以我设置一下
665
00:32:46,765 --> 00:32:49,599
the background of this to something, so I'm gonna
这个按钮的背景色
666
00:32:49,601 --> 00:32:52,803
go down that turns out to be something that button inherits
所以我往下滑，发现这个按钮的背景
667
00:32:52,805 --> 00:32:55,205
from view, right here background.
继承于 view，就在这里
668
00:32:55,207 --> 00:32:59,042
So I can set it by, you know, using crayons,
所以我可以用不同色的蜡笔来改变它
669
00:32:59,044 --> 00:33:02,045
okay, whatever you can use sliders or I can
okay, 无论你用什么都行
670
00:33:02,047 --> 00:33:05,782
use maybe recently used ones like here's light grey, okay?
我可以用我最近用过的颜色，比如浅灰，okay?
671
00:33:05,784 --> 00:33:08,185
So, I've substituted my nice little background here so,
这样我就更换了我们这个按钮的背景颜色
672
00:33:08,187 --> 00:33:10,721
you know, you can go and edit these things and make them
你们可以编辑这些东西，把按键变成任何你们想要的样子
673
00:33:10,723 --> 00:33:14,858
look however you want, what's interesting about what's going
有趣的地方在这
674
00:33:14,860 --> 00:33:18,261
on here is this...there's no code generation step gonna
这里并没有产生任何代码
675
00:33:18,263 --> 00:33:21,932
happen here. You're actually editing these objects live.
你只是改变了这个按键的样子
676
00:33:21,934 --> 00:33:25,669
Okay. By changing things in the inspector you're sending
通过改变检测窗口里的东西
677
00:33:25,671 --> 00:33:29,172
messages to this button to set the way it is and
你在给按键发送信息，把它设置成你想要的样子
678
00:33:29,174 --> 00:33:33,610
then the Xcode has a way to essentially freeze dry
接着 Xcode 就有办法完成你的请求
679
00:33:33,612 --> 00:33:35,545
all the attributes, and it's object oriented.
改变按钮的属性，这是面向对象
680
00:33:35,547 --> 00:33:37,147
In other words, the objects are participating and
换言之，Xcode 能够把这些操作
681
00:33:37,149 --> 00:33:42,419
freeze drying themselves. And in fact, the whole mechanism
转换成对按键对象的代码的操作，事实上
682
00:33:42,421 --> 00:33:45,856
of this part of Xcode which we call interface builder,
Xcode 的这套机制被我们叫做 ”interface builder”
683
00:33:45,858 --> 00:33:48,925
cuz we're building our user interface, is extensible and
因为我们在为用户做界面，它是可扩展的
684
00:33:48,927 --> 00:33:51,495
you can put your own objects in here, okay.
你也可以在这里加入自己的对象
685
00:33:51,497 --> 00:33:53,563
Your own things they draw, custom drawing or whatever.
UI上所画的一切你都可以自己控制
686
00:33:53,565 --> 00:33:56,633
And we'll show you all about that as the weeks go by.
过几周我就会给你们展示
687
00:33:56,635 --> 00:33:59,603
All right. So, I have one button here, that's good.
好的，现在我有一个按钮在这，非常好
688
00:33:59,605 --> 00:34:01,171
I could even run my app right now.
我甚至已经可以运行这个app了
689
00:34:01,173 --> 00:34:03,673
So how do I run this application? You
那么我如何运行它呢？
690
00:34:03,675 --> 00:34:07,544
go up here to the top, you see where it says iPhone 6s Plus.
看上来，在顶栏这，你能看到这上面写着 “iPhone 6s Plus”
691
00:34:07,546 --> 00:34:10,914
This is actually a list of simulators that you can choose
这实际上是你要选择的模拟器列表
692
00:34:10,916 --> 00:34:14,985
to run your app on, all right? So, you could also run it on
来运行你的app，明白了吗？当然你也可以在一个设备上运行它
693
00:34:14,987 --> 00:34:18,889
a device. If you connected a device and did that team thing
如果你连接了设备然后配好对
694
00:34:18,891 --> 00:34:22,626
I was talking about, you can run it on your device here but
我现在讲的是，你可以在你的设备上运行app
695
00:34:22,628 --> 00:34:23,460
I didn't connect a device so
但我没有连接任何设备
696
00:34:23,462 --> 00:34:25,529
I'm going to run it on an iPhone 6. Okay, so
所以我打算在 iPhone 6 模拟器上运行它
697
00:34:25,531 --> 00:34:30,000
I just pick iPhone 6 and then I just press Play right here,
我只需要选择 iPhone 6 接着按下这个运行键
698
00:34:30,002 --> 00:34:32,969
so we press play it's gonna bring up
好了我们按下运行键，它会产生一个
699
00:34:32,971 --> 00:34:34,571
an iPhone simulator okay and
iPhone模拟器
700
00:34:34,573 --> 00:34:36,206
then the iPhone simulator is gonna run this app.
接着我们的app就会在这个iPhone模拟器上运行
701
00:34:36,208 --> 00:34:39,309
Now this iPhone simulator that you see appearing right here,
现在你看到，这个iPhone模拟器上
702
00:34:39,311 --> 00:34:42,112
it's showing our app. This is more than just our app.
有了我们的app，当然模拟器有的不只是我们的app
703
00:34:42,114 --> 00:34:45,649
This is actually a full simulator of the iPhone.
它可以模拟iPhone的各种行为
704
00:34:45,651 --> 00:34:48,485
And in fact, if I go Hardware, Home, that's
实际上，我点击这个 “Hardware”，“Home”
705
00:34:48,487 --> 00:34:51,221
just like pressing the Home button. You know the little
它就会像真正按在 home 键上一样，就像
706
00:34:51,223 --> 00:34:55,058
Home button on your iPhone? Watch this. Press Home, and
按你iPhone上的 home 键，看，点击home
707
00:34:55,060 --> 00:34:57,227
it goes to here. And I got Settings, Photo,
它就回到主界面，这里就是些设置，相册
708
00:34:57,229 --> 00:35:02,499
Calendar, Safari, other apps, etc. Okay, and here's my app.
日历，Safari，各种app。Okay?这里是我的app
709
00:35:02,501 --> 00:35:05,669
This my assistive app, calculator has no app icon.
这就是我的计算机app，目前还没有一个图标
710
00:35:05,671 --> 00:35:08,038
But, there it is. Now, I can go back. Okay? So
但是看这里，我可以点进去，okay？
711
00:35:08,040 --> 00:35:11,508
it's really simulating the device here. Now,
所以它像一个真正的iPhone
712
00:35:11,510 --> 00:35:16,680
what happens if I touch this button? Nothing. Okay?
那么现在我按下这个按钮会怎样呢？什么都不会发生，okay？
713
00:35:16,682 --> 00:35:19,149
That's because we haven't really taught our
因为当这个按钮按下的时候
714
00:35:19,151 --> 00:35:23,487
calculator app what to do when this button is touched. So
我的计算器并不知道该做些什么，我还没有教它
715
00:35:23,489 --> 00:35:26,089
let's go do that. Now how are we gonna do that?
所以我们现在来教它，怎么做呢？
716
00:35:26,091 --> 00:35:28,959
Remember I told you that the V, the view here is kind of
记得我告诉过你们的, MVC 里的 V
717
00:35:28,961 --> 00:35:31,761
generic UI buttons and sliders and that there's a model which
这个按键是一个原生的按键，我们现在还没有
718
00:35:31,763 --> 00:35:34,931
we don't have yet okay? And then there's the controller.
一个 model 来控制它，okay？这是我们的 controller
719
00:35:34,933 --> 00:35:37,968
So the way that touching on buttons causes anything to
按下按按键发生的所有事情都是这个 controller 来完成的
720
00:35:37,970 --> 00:35:42,038
happen is via the controller. So somehow we have to connect
所以我们得把按钮和 controller 连接起来
721
00:35:42,040 --> 00:35:45,542
this button up to our controller. In fact,
所以我们得把按钮和 controller 连接起来
722
00:35:45,544 --> 00:35:47,544
what we wanna do is, when we touch this button,
所以，我现在需要做的，就是当我们按下这个按钮时
723
00:35:47,546 --> 00:35:51,882
we wanna invoke a method in our controller object, right?
我们想调用 controller 中的一个方法，好吗？
724
00:35:51,884 --> 00:35:53,183
Sounds nice and object oriented.
听起来非常面向对象
725
00:35:53,185 --> 00:35:56,286
That's what we wanna do. So how do we set that up, okay?
那么我们如何完成这件事呢？
726
00:35:56,288 --> 00:35:59,489
We're gonna set that up by getting the controller and
我们需要把 controller 和 view 放在
727
00:35:59,491 --> 00:36:02,592
the view on screen at the same time. Okay, and
同一个屏幕上，okay？
728
00:36:02,594 --> 00:36:05,362
then we're gonna wire it up graphically with the mouse.
然后我们用鼠标把它们连接起来
729
00:36:05,364 --> 00:36:06,630
So let's get both on there at the same time.
现在我们把它们两个放在屏幕上
730
00:36:06,632 --> 00:36:08,865
The way we do that is with this button right here this
怎么做呢？看见编辑栏右边的
731
00:36:08,867 --> 00:36:12,469
little round circle the assistant editor. This brings
小圈圈了吗？点击它可以
732
00:36:12,471 --> 00:36:17,207
up the controller and the view on screen at the same time
把 controller 和 view 放在同一个屏幕上
733
00:36:17,209 --> 00:36:20,277
again I have low resolution so it's all kinda smashed so
这个界面现在很小，那么现在关闭
734
00:36:20,279 --> 00:36:23,580
let's close our navigator and close our utilities. Okay,
左边和的导航栏和右边的工具栏，okay？
735
00:36:23,582 --> 00:36:27,584
and we can share this space however we want. Okay, so
我们可以随便改变，okay？
736
00:36:27,586 --> 00:36:28,251
we have plenty of room for our code.
现在我们有足够的空间展示代码了
737
00:36:28,253 --> 00:36:32,589
And here's our controller. So, now this is gonna seem wacky,
这是我们的 controller，这可能看起来会有一点怪异
738
00:36:32,591 --> 00:36:34,591
but it's actually really, really cool. Okay.
但实际上这非常，非常，酷，okay？
739
00:36:34,593 --> 00:36:37,694
The way that we hook up that button, to call a method in
我们现在把按钮和 controller 里的方法连接起来
740
00:36:37,696 --> 00:36:41,932
our controller, is by holding down the control key, okay.
只需要按住 control 键
741
00:36:41,934 --> 00:36:43,066
I'm gonna hold down the control key.
好，我现在按住了 control 键
742
00:36:43,068 --> 00:36:47,938
And drag, from the button [LAUGH] into my coat, okay.
然后拖动，从按钮拖动到我的代码里来，okay？
743
00:36:47,940 --> 00:36:50,774
Now I know it really seems weird but it's cool, okay.
我知道现在看起来非常怪异，但是也很酷，okay？
744
00:36:50,776 --> 00:36:53,843
So I can put it wherever I want in my class here. And
我可以随意拖动它到我的代码里面
745
00:36:53,845 --> 00:36:57,514
when I let go, it's gonna say okay, what kind of connection
然后当我松开鼠标，需要设置些东西
746
00:36:57,516 --> 00:37:00,817
do you wanna make between this user interface object and
比如我们UI对象和 controller 之间
747
00:37:00,819 --> 00:37:03,086
your controller? And there's really two choices,
需要什么样的连接？这里有2个选择
748
00:37:03,088 --> 00:37:04,521
one is called an outlet which I'm gonna talk
一个是调用 “outlet”，这个我稍后再讲
749
00:37:04,523 --> 00:37:07,290
about in a moment and the other one is called an action.
另一个叫做 “action”
750
00:37:07,292 --> 00:37:10,493
So an action is when you want something that happens in UI
“action” 就是当UI中发生了一些事件后，
751
00:37:10,495 --> 00:37:12,762
to invoke a method in your controller. Okay?
controller 里的方法将被调用，okay？
752
00:37:12,764 --> 00:37:15,999
Exactly what we want here, that's what an action is. So
这就是我们想要的，这就是 “action” 的作用
753
00:37:16,001 --> 00:37:18,702
here it's asking the name, it wants to know the name
那么这里需要一个名字，它需要知道这个方法的名字
754
00:37:18,704 --> 00:37:22,239
of the method. So here I'm touching a digit button,
因为我需要按下一个按钮
755
00:37:22,241 --> 00:37:24,908
so I'm gonna call this touchDigit. Okay.
所以我这在输入 “touchDigit”，okay？
756
00:37:24,910 --> 00:37:26,910
So this is just the name of the method that,
这就是在我的 controller 里
00:37:26,912 --> 00:37:29,479
is gonna be created in my controller.
建立的方法的名字
758
00:37:29,481 --> 00:37:31,514
Notice that my method can have arguments.
注意，我的方法可以有参数
759
00:37:31,516 --> 00:37:32,882
You see down here where it says arguments?
你看下面，这里写着 ”Arguments”
760
00:37:32,884 --> 00:37:37,053
It could have no arguments. Okay. Which is fine, right.
它可以不需要参数, 没有任何问题。
761
00:37:37,055 --> 00:37:38,622
I don't want an argument, that'd be fine.
我不需要参数，这样设置就好了
762
00:37:38,624 --> 00:37:42,225
It can have one argument which is the sender, in other words,
也可以有一个参数，叫做 sender，换言之
763
00:37:42,227 --> 00:37:44,728
the button that is sending me this method, okay.
这个按钮会把我送到这个方法里来，okay？
764
00:37:44,730 --> 00:37:47,297
That's really valuable argument, okay. Especially in
这是个很有价值的参数，okay？
765
00:37:47,299 --> 00:37:50,033
this case because I'm gonna have a whole bunch of buttons.
特别是当我有很多按键的时候
766
00:37:50,035 --> 00:37:52,235
They're each gonna be sending touch digit, and
每一个按键都会发送一个数字
767
00:37:52,237 --> 00:37:53,336
I wanna know which one sent it to me.
我会想知道哪个按键发送给我了信息
768
00:37:53,338 --> 00:37:56,506
So the fact that it's gonna pass itself as an argument to
事实上，按键会把它自己当作参数
769
00:37:56,508 --> 00:37:59,843
this method is great. The only problem is if you see this
传递给方法，有个问题就是
770
00:37:59,845 --> 00:38:03,246
type right here any object. That's going to be the type
你看见这里有一个 “any object”，它的类型就是一个 object
771
00:38:03,248 --> 00:38:05,982
of the object. It's this generic any [LAUGH] object
它可以是右边任意类型的对象
772
00:38:05,984 --> 00:38:08,184
thing right here. We don't want that. Okay?
我们不需要，okay？
773
00:38:08,186 --> 00:38:12,522
So when you're doing your homework don't miss this step.
当你做家庭作业的时候，不要错过这一步
774
00:38:12,524 --> 00:38:17,527
Okay? Change this from any object to UI button.
okay？把它从 “any object” 改成 “UIButton”
775
00:38:17,529 --> 00:38:20,630
Because of course the thing sending us this message is UI
因为发送给我们消息的显然是一个 UIbutton
776
00:38:20,632 --> 00:38:23,833
button. It's unfortunate that this is not the default but
不幸的是它不是默认设置
777
00:38:23,835 --> 00:38:27,304
you must do this. Okay? So, this I wanna click Connect,
所以你必须自己搞定，okay？现在，我来点击 “Connect”
778
00:38:27,306 --> 00:38:30,440
this is just what event is causing this a touch on
这是按下按键后会触发的事件
779
00:38:30,442 --> 00:38:34,277
the button that goes up inside the buttons bounds. Okay?
按键会重新“弹起来”
780
00:38:34,279 --> 00:38:36,046
So I'm gonna hit connect right here and
所以我现在点击一下
781
00:38:36,048 --> 00:38:37,614
it's gonna write the code for a method.
它会写下这个方法的代码
782
00:38:37,616 --> 00:38:40,917
You're gonna see your first Swift method here we go. Okay?
你会在这里看到第一个 swift 方法，okay？
783
00:38:40,919 --> 00:38:44,354
This is your first Swift method. Now this is actually
这是你的第一个 swift 方法
784
00:38:44,356 --> 00:38:46,923
not part of Swift. Okay, it's not part of this method.
这里不是 swift 的一部分，okay？它不是方法的一部分
785
00:38:46,925 --> 00:38:49,659
This is something Xcode puts in here. So that this little
这是 Xcode 放在这里的东西
786
00:38:49,661 --> 00:38:52,996
round circle appears. You see that round circle right there?
所以这里有一个小圈圈，你看了这个小圈圈了吗？
787
00:38:52,998 --> 00:38:54,764
If I mouse over that round circle,
如果我把鼠标放上去
788
00:38:54,766 --> 00:38:59,502
you see how it shows me what thing in my view is hooked up
你可以看见，方法和UI里的东西是怎样连接的
789
00:38:59,504 --> 00:39:02,072
to this method you see? Okay so that's what this is so
看见了吗？ 这就是它的作用
790
00:39:02,074 --> 00:39:06,242
that's really not part of the Swift method. Okay so this is
它不是 swift 方法的一部分
791
00:39:06,244 --> 00:39:10,547
all the Swift method. Okay so what is Swift method syntax?
这才是 swift 里的方法，okay？swift 的方法语法是怎样的呢？
792
00:39:10,549 --> 00:39:14,184
Func, okay, func means this is a function on a class,
先是一个func，func 代表的是这个类里的一个函数
793
00:39:14,186 --> 00:39:17,420
a method is essentially a function on a class, right?
方法本质上就是类里的函数，好吗？
794
00:39:17,422 --> 00:39:21,858
I suppose this could be called Method. Like the breaking bad
这可以被叫做方法。
795
00:39:21,860 --> 00:39:25,261
version of what you'll call meth maybe. But func is good,
和《绝命毒师》里的冰毒发音类似，但是 func 是好的
796
00:39:25,263 --> 00:39:28,631
func is good because you can have global funcs also.
func 还好在你还可以写全局函数
797
00:39:28,633 --> 00:39:32,335
Okay, you can have the same syntax outside of a class,
使用同样的语法，你可以在类的外面写一个函数
798
00:39:32,337 --> 00:39:34,871
description outside of these braces.
定义在这些大括号的外面
799
00:39:34,873 --> 00:39:36,306
And it will be a global function.
这样它就是个全局函数
800
00:39:36,308 --> 00:39:37,540
And we're gonna see some of those.
我们之后会见到一些全局函数
801
00:39:37,542 --> 00:39:39,042
Like square root is a function I'm gonna
就像平方根函数
802
00:39:39,044 --> 00:39:42,345
use when I add square root to my calculator. All right, so
比如，当我在计算器里加上根号的时候
803
00:39:42,347 --> 00:39:44,748
that's the key words just like class is the key word for
“class”，这是创建一个类的的关键字
804
00:39:44,750 --> 00:39:47,684
creating a class. Func is the key word for adding a method.
“func” 是添加一个方法的关键字
805
00:39:47,686 --> 00:39:52,155
Touch digit is the name, obviously of this method.
“touchDight” 是它的名字，显然它是一个方法
806
00:39:52,157 --> 00:39:54,691
Parentheses has the arguments, okay?
括号内可以有参数
807
00:39:54,693 --> 00:39:58,561
We only have one argument called sender of type
我们只有一个叫做 “sender” 的参数
808
00:39:58,563 --> 00:40:02,599
UIButton, so that's what : UIButton means.
类型是 UIButton， 这就是 UIButton 的意思
809
00:40:02,601 --> 00:40:06,102
Any time you're defining a type of something in Swift,
当你在swift定义一个东西的类型的时候
810
00:40:06,104 --> 00:40:08,838
colon and the type after the name of the thing.
使用冒号，后面跟着它需要的类型的名字
811
00:40:08,840 --> 00:40:10,807
Okay, and that's true for arguments to methods,
方法中的参数也是这样
812
00:40:10,809 --> 00:40:12,609
it's also true for local variables, everything.
局部变量，所有东西，都是这样
813
00:40:12,611 --> 00:40:15,812
Colon and the type, okay? Now if we had more arguments,
冒号，然后类型名字，okay？现在如果我们有多个参数
814
00:40:15,814 --> 00:40:20,617
they would just be separated by comma, like otherArgument
它们应该被逗号分隔开，如同这个 otherArgument
815
00:40:20,619 --> 00:40:24,654
might be an Int, okay, so I put an Int there.
它可以是一个Int， okay？所以我写一个 Int 在这
816
00:40:24,656 --> 00:40:26,990
So, this is another argument, second argument here, and
所以这是第二个参数
817
00:40:26,992 --> 00:40:29,926
I can have as many as I want, and they each have to have
我需要多少个参数都可以，每一个都需要一个参数名
818
00:40:29,928 --> 00:40:34,030
a key word, which describes, what they are. If this had
来表示它们是干什么的
819
00:40:34,032 --> 00:40:39,068
a return value, it looks like this. Returns String. Okay, or
如果这个方法有返回值，就这样写，返回一个 String
820
00:40:39,070 --> 00:40:41,938
returns Double. Okay, something like that.
或者返回一个 Double, okay?就像这样
821
00:40:41,940 --> 00:40:45,809
That's how a return looks like, okay. Now I'm gonna
return 就这样写，okay？
822
00:40:45,811 --> 00:40:48,445
take a timeout here from writing our calculator and
现在我要开始写我们的计算器了
823
00:40:48,447 --> 00:40:50,180
just show you what its like to call a method.
教你如何调用一个方法
824
00:40:50,182 --> 00:40:52,916
Okay? This is we're declaring the method. What if I wanted
Okay? 我们在这里声明了一个方法
825
00:40:52,918 --> 00:40:55,919
to call this method on myself? Okay it would be recursive
如果我自己想调用这个方法呢？那么就会出现递归
826
00:40:55,921 --> 00:40:57,887
here because I'm inside touched as your butt.
因为这是自己调用自己
827
00:40:57,889 --> 00:41:00,089
I just wanna show you the syntax for calling okay?
我只是展示一下调用方法的语法
828
00:41:00,091 --> 00:41:02,325
So if I want to send something to myself.
如果我想给我自己发送点信息
829
00:41:02,327 --> 00:41:05,495
I use the key word self, and then to send a message it's
我用关键字 “self”，然后发送信息
830
00:41:05,497 --> 00:41:08,298
just like Java you press dot, okay?
如果JAVA一样，按下“.”，okay？
831
00:41:08,300 --> 00:41:10,333
The thing you want to send it to dot and
你想发送什么，按下一个“.”
832
00:41:10,335 --> 00:41:14,504
then you type the name of the method or of the property if
然后输入你需要调用的方法或属性
833
00:41:14,506 --> 00:41:17,207
you wanna access an instance variable exactly the same.
如果你想调用一个实例变量，也是相同的办法
834
00:41:17,209 --> 00:41:17,740
The name of the property or
对某个对象，你想调用的属性的名字
835
00:41:17,742 --> 00:41:20,043
the method that you wanna access in that object.
或者方法的名字
836
00:41:20,045 --> 00:41:22,645
So here I want to do touchDigit and you're going
在这我想调用 touchDigit
837
00:41:22,647 --> 00:41:25,014
to notice here that Xcode is helping me a lot as I type,
你会发现 Xcode 会帮助我输入
838
00:41:25,016 --> 00:41:27,817
it's giving me lists of things that I can choose that
给我一张列表供我选择
839
00:41:27,819 --> 00:41:30,987
are likely. Here touchDigit, it's putting that on the top
这里，touchDigit，在最顶上
840
00:41:30,989 --> 00:41:33,356
cuz that's the only method that is in my class.
因为这是这个类中的唯一的方法
841
00:41:33,358 --> 00:41:36,092
I inherit a lot of methods from my superclasses but
我从父类中继承了非常多的方法
842
00:41:36,094 --> 00:41:38,862
this is the only one in my class and in fact if I just
但这是这个类中的唯一的方法，事实上
843
00:41:38,864 --> 00:41:41,531
press Tab, it starts filling it out. I'm not even,
如果我按下 Tab，它会自动补全，不需要全部手打
844
00:41:41,533 --> 00:41:44,167
I don't even have to type it okay, cuz it knows that's what
因为 Xcode 知道我们想要什么
845
00:41:44,169 --> 00:41:48,771
I want. Now, it takes two argument. The first argument
现在它有两个参数
846
00:41:48,773 --> 00:41:51,508
you just put it in. So the first argument was a button so
这里的第一个参数是一个 button， 所以
847
00:41:51,510 --> 00:41:55,078
maybe, you know, some button or something like that. Okay,
我输入 someButton 之类的东西，okay
848
00:41:55,080 --> 00:41:56,446
some variable that would have to be a button.
某些变量会是一个 button
849
00:41:56,448 --> 00:41:59,115
I don't have one but that's what it would be.
现在我没有这个变量，不过以后会有的
850
00:41:59,117 --> 00:42:00,783
The second argument here, okay, and
这里的第二个参数
851
00:42:00,785 --> 00:42:03,753
I'm just hitting Tab to go to each argument, is an Int,
我按了 Tab 键来跳到每个参数，它是一个 Int
852
00:42:03,755 --> 00:42:06,256
so let's say I put 5, okay, so this is how I would
那么我放一个5在这里，okay，我就打算这么做了
853
00:42:06,258 --> 00:42:08,958
call this thing. Now what's interesting about this is,
现在，有趣的事
854
00:42:08,960 --> 00:42:12,662
notice that this keyword is actually included,
注意这个关键字也出现了
855
00:42:12,664 --> 00:42:15,532
in other languages this would look like this. All right?
在其它语言中会是这个样子，All right?
856
00:42:15,534 --> 00:42:17,934
You would just have the two arguments, sender and
你只需要两个参数，sender 和 argument
857
00:42:17,936 --> 00:42:22,272
argument, but here in Swift, sorry, in Swift,
但是在 swift 里
858
00:42:22,274 --> 00:42:27,844
we put the explicit, name of the argument here for
需要非常详尽，参数名也需要写出来
859
00:42:27,846 --> 00:42:30,680
readability and clarity except for we don't do it with
这是为了可读，清晰，但我们不写第一个参数的参数名
860
00:42:30,682 --> 00:42:35,151
the first one. Okay? The first one we don't do.
okay？不要写第一个参数的参数名
861
00:42:35,153 --> 00:42:37,620
That's because usually the first one is implicit in
因为 swift 里通常都这样做
862
00:42:37,622 --> 00:42:41,758
the name, okay? But, that's what, now there is a way to
okay？非得写出这个参数名的话
863
00:42:41,760 --> 00:42:44,394
make it so you have to do the first one, for but generally
也是有一个方法的，但是最好别这样做
864
00:42:44,396 --> 00:42:46,729
we don't. In other words we don't type sender this.
换言之不要把 sender 写出来
865
00:42:46,731 --> 00:42:48,598
And in fact, it's wrong to type sender that.
事实上，这样做是错误的
866
00:42:48,600 --> 00:42:50,967
>> Would that be an error?
这样会造成错误吗？
867
00:42:50,969 --> 00:42:51,000
>> It would be an error.
是的，这会造成错误
868
00:42:51,002 --> 00:42:55,705
It would not compile. Okay? So that's the syntax for sending.
它不会编译，okay？这就是发送一个消息的语法了
869
00:42:55,707 --> 00:42:58,041
And you'll have to get used to putting these in for
你们会逐渐习惯这样的写法
870
00:42:58,043 --> 00:43:00,944
all the subsequent arguments besides the first.
除了第一个，其他的参数都要写参数名
871
00:43:00,946 --> 00:43:04,447
Okay. So let's gret rid of all this stuff we added. So
okay，删掉这些我们加上的东西
872
00:43:04,449 --> 00:43:08,084
here's our touchDigit. let's just have touchDigit
这是我们的 touchDigit，现在让它
873
00:43:08,086 --> 00:43:10,587
print something out to the console. Okay?
打印个什么，输出到控制台里，okay？
874
00:43:10,589 --> 00:43:11,621
Great thing to know for debugging, and
这是 debug 的好方法，什么的
875
00:43:11,623 --> 00:43:14,958
stuff like that. You do that with the method print. And
在方法里写上打印语句
876
00:43:14,960 --> 00:43:17,026
I'm just going to say, print touchDigit.
我打印一个 “touchDigit”
877
00:43:17,028 --> 00:43:19,562
So it's gonna print touchDigit after the console.
它会在控制台里打印一个 “touchDigit” 出来
878
00:43:19,564 --> 00:43:22,899
Notice no semicolons on the end of lines or anything like
注意，句尾没有分号或其他东西
879
00:43:22,901 --> 00:43:27,270
that. In Swift the carriage return is the end of line.
swift 里，回车表示这一行的结束
880
00:43:27,272 --> 00:43:29,072
And if you wanna put two statements on the same line
如果你想把两条语句打在一行里
881
00:43:29,074 --> 00:43:30,440
you can use a semicolon in between, but
在语句中间加上分号就行了
882
00:43:30,442 --> 00:43:34,077
generally the carriage return is the end of line, okay? So
但一般情况，我们用回车作为语句结尾，okay？
883
00:43:34,079 --> 00:43:37,046
we print touch digit here. Let's go ahead and run and
所以把 print 语句写在这
884
00:43:37,048 --> 00:43:45,188
see if that works. Changes our simulator.
现在运行一下看它是否能正常工作，改变下我们的模拟器
885
00:43:45,190 --> 00:43:45,955
Now, where is the console?
现在，控制台在哪里？
886
00:43:45,957 --> 00:43:49,258
It's going to appear magically at the bottom here as soon as
当有东西出现在控制台里的时候
887
00:43:49,260 --> 00:43:51,060
something appears on the console. So, here we go.
它会神器地从底部出现，所以，here we go
888
00:43:51,062 --> 00:43:55,164
Ready? 5, there it is. There's the console in here. 5 again,
Ready? 5, 它出来了，这就是控制台，再按一下，5
889
00:43:55,166 --> 00:43:57,800
okay we got two of them. Okay, we press a whole bunch of
okay，我们现在有2个5了
890
00:43:57,802 --> 00:44:00,403
times, and get a whole bunch of them. Go back here, scroll
我们按几次5它就出现几次，回到这里来
891
00:44:00,405 --> 00:44:04,507
around. This bottom area has the console on the right,
滚动一下，底部区域里，右边是控制台
892
00:44:04,509 --> 00:44:07,944
and your debugger output on the left. This is where when
左边是调试器，debug 的时候你会用到
893
00:44:07,946 --> 00:44:09,712
we start to do debugging you'll see it on the left.
它会出现在左边
894
00:44:09,714 --> 00:44:13,416
You can hide one or the other, like we could hide our
也可以隐藏它们，我们可以隐藏调试器
895
00:44:13,418 --> 00:44:16,252
debugger and just see our console here. Okay, so
只留下我们的控制台，okay？
896
00:44:16,254 --> 00:44:19,222
this is cool, this is great. Except for we're gonna
这很酷，非常棒
897
00:44:19,224 --> 00:44:23,292
have a lot of buttons not just this one button, this 5.
但是如果有一堆按键而不是一个呢？这是个5
898
00:44:23,294 --> 00:44:26,195
Okay, so let's go back to our UI. By the way you can hide
现在回到我们的UI，顺便说一下
899
00:44:26,197 --> 00:44:29,565
this thing by either dragging it down or pressing this
你可以通过拖拽来隐藏它们，或者点击这个按钮
900
00:44:29,567 --> 00:44:32,935
button up here. Okay, just like you hide this thing
就像你点击这个隐藏这个
901
00:44:32,937 --> 00:44:36,105
with that you hide with this with that. All right, so we'll
就像你点击这个隐藏这个
902
00:44:36,107 --> 00:44:39,509
stop. Now I wanna make a whole keypad worth of buttons here.
停止运行，现在我想做出一个完整的键盘
903
00:44:39,511 --> 00:44:41,611
Instead of just having a 5, I want a whole bunch.
不只是一个5，而是所有数字
904
00:44:41,613 --> 00:44:42,979
So I'm gonna do that with copy and paste.
我通过复制粘贴来完成
905
00:44:42,981 --> 00:44:47,550
Copy, paste okay? There we go, paste another one here.
复制，粘贴，okay？好了，再粘贴一个
906
00:44:47,552 --> 00:44:51,387
Okay? Maybe this is our 4, 5 and 6.
okay？这个是我们的4，5，6
907
00:44:51,389 --> 00:44:55,525
I can actually select all three and copy paste. Okay.
我可以选中这三个，再复制和粘贴
908
00:44:55,527 --> 00:45:00,463
1, 2, and 3 and may you paste again.
1，2，3，然后再粘贴一次
909
00:45:00,465 --> 00:45:05,635
Go up here. 7, 8, 9 and we'll copy and
移到上面来，7，8，9，再复制
910
00:45:05,637 --> 00:45:11,407
paste one more to make our 0. Okay?
粘贴出我们的0，okay？
911
00:45:11,409 --> 00:45:15,511
So here's our nice little keypad right here. And,
这就是我们的小键盘了
912
00:45:15,513 --> 00:45:20,583
now we can run. And we'll notice
现在我们运行它
913
00:45:20,585 --> 00:45:24,287
that all of these buttons are sending touch digit. You see?
注意所有的按键都会发送信息给 touchDigit
914
00:45:24,289 --> 00:45:26,055
Okay, so they're all sending touch digit.
他们都会发送信息给 touchDigit
915
00:45:26,057 --> 00:45:28,991
Which is good, that's kind of nice. We can also tell they're
很棒，很不错，我们还能通过这个小圈圈
916
00:45:28,993 --> 00:45:30,259
all sending it with this little circle.
看到它们连接在一起
917
00:45:30,261 --> 00:45:32,395
Watch what happens when I mouse over. You see?
看看我移开鼠标会发生什么？看见了吗？
918
00:45:32,397 --> 00:45:35,898
It's selecting them all to say they're all sending it. Okay.
选中了全部按键，他们都能发送信息
919
00:45:35,900 --> 00:45:40,169
But, we really wanna know which one is sending it. Okay.
但，我们需要知道是那一个按键发送了信息，okay
920
00:45:40,171 --> 00:45:42,472
So we're gonna have to look at this sender argument,
所以我们需要看看这个 sender 参数
921
00:45:42,474 --> 00:45:45,775
to see which button is sending us this touch digit.
看看是哪个按键发给它了信息
922
00:45:45,777 --> 00:45:48,511
Okay. So I'm gonna create a local variable here.
okay，我打算建立一个局部变量
923
00:45:48,513 --> 00:45:51,714
This is how you create a local variable, var. The name,
这就是如何建立一个局部变量，var，然后是变量名
924
00:45:51,716 --> 00:45:55,451
which I'm gonna call digit. And I'm gonna set it equal to,
我打算叫它 digit，我打算把它设置成
925
00:45:55,453 --> 00:45:59,522
whatever I get from asking the sender, what its title is.
给被按下的按键的数字，按键的名字
926
00:45:59,524 --> 00:46:02,658
Okay? Now, how do I do that? Well, we know that we
okay？怎么做呢？ 我们知道
927
00:46:02,660 --> 00:46:06,229
send a message to something by doing the object, right,
得到这个名字肯定和sender这个对象有关，对吗？
928
00:46:06,231 --> 00:46:11,434
sender and a dot, okay? Unfortunately, button has, mm,
sender 然后一个“.”，okay？不幸的是
929
00:46:11,436 --> 00:46:15,471
quite a few methods, okay? I mean probably hundreds, okay?
按键拥有很多方法，okay？可能几百个，okay？
930
00:46:15,473 --> 00:46:18,808
Because it's inheriting things from control and view and
因为它继承于 control，view
931
00:46:18,810 --> 00:46:18,875
stuff like that.
类似的东西
932
00:46:18,877 --> 00:46:21,978
So it's a pretty much, a bummer trying to find out how
所以找到按键名似乎还是很困难
933
00:46:21,980 --> 00:46:25,681
to know what to give this. So we need documentation here.
所以我们在这种时候
934
00:46:25,683 --> 00:46:28,184
We need some help, okay. So the way to do that
就需要文档的帮助，okay？怎么做呢？
935
00:46:28,186 --> 00:46:30,219
is you're gonna hold down the option key, okay.
按下你的键盘上的 option 键，okay？
936
00:46:30,221 --> 00:46:32,321
I already showed you Control is an important key for
我已经告诉你了 control 键很重要
937
00:46:32,323 --> 00:46:35,792
dragging between your view and your thing. Now Option is
特别是对UI拖拽来说，现在 option 键
938
00:46:35,794 --> 00:46:38,194
an important key. And when you hold down Option,
也非常重要，当你按下 option 键
939
00:46:38,196 --> 00:46:40,029
look what happens when you mouse over things.
再移动鼠标，看看会发生什么
940
00:46:40,031 --> 00:46:43,900
They get this dash blue underline going. And what that
下方出现了蓝色虚线，这意味着
941
00:46:43,902 --> 00:46:46,536
means is if you click on them Xcode's gonna tell you
如果你点击了它们，Xcode 会告诉你
942
00:46:46,538 --> 00:46:49,705
as much as it can about that thing. So let's click on
关于它们的一切信息，所以我们在
943
00:46:49,707 --> 00:46:53,309
UIButton and when we do we get this little window that
UIButton 这点击，我们得到了一个小窗口
944
00:46:53,311 --> 00:46:57,547
has a complete description of UIButton in here. And really
它拥有关于 UIButton 完整信息，非常重要的是
945
00:46:57,549 --> 00:47:01,150
importantly down at the bottom it has a reference link.
在最底下，有一个引用链接
946
00:47:01,152 --> 00:47:03,686
See this reference link? And if I click this, this is gonna
看见这个引用链接了吗？如果我点它一下
947
00:47:03,688 --> 00:47:07,757
take me to the documentation for UIButton. So there we go.
它会把我带到 UIButton 的文档里，所以我们点击它
948
00:47:07,759 --> 00:47:10,226
Here it is, UIButton. Here's all the methods and
这就是了，UIButton，这是它所有的方法
949
00:47:10,228 --> 00:47:14,530
properties in UIButton. Here's all the description of it.
所有的属性，所有的关于它的描述
950
00:47:14,532 --> 00:47:19,769
And there is all kinds of text here that describes all
各种各样的文本来告诉你这些方法
951
00:47:19,771 --> 00:47:22,171
the methods and how they work, okay.
是如何工作的，okay？
952
00:47:22,173 --> 00:47:26,375
Now, I need to find something about the title so
现在，我要找出关于 ”title”(标题) 的一些信息
953
00:47:26,377 --> 00:47:29,846
I could search here by just doing Cmd+f to search, and
我可以按下Cmd+f进行搜索
954
00:47:29,848 --> 00:47:32,982
I could search for title but unfortunately the title
我可以搜索一下 “title”，不幸的是
955
00:47:32,984 --> 00:47:37,286
is mentioned a lot, see? So that's no good. So
“title” 在文档里被提及的太多了，很不好
956
00:47:37,288 --> 00:47:39,522
I can go over here to the summary of all the methods and
然后我可以看下 summary 这里，它有所有的方法和属性
957
00:47:39,524 --> 00:47:42,792
properties. We could look here. Getting dimensions,
我们可以看过来，看看它包括些什么
958
00:47:42,794 --> 00:47:46,128
no I don't wanna do that. Configuring edge insets we
不，我不想这样做，我们甚至还不知道什么是
959
00:47:46,130 --> 00:47:48,998
don't even know what that is yet. Getting the current state
“Configuring edge insets”，“获取目前状态”这个听起来
960
00:47:49,000 --> 00:47:50,700
that sounds pretty good, getting the current state.
还不错，获取目前状态
961
00:47:50,702 --> 00:47:53,302
Let's see what we've got, button type okay here's how I
看看这里有什么？按键类型，okay，它在这
962
00:47:53,304 --> 00:47:54,670
can get the button's type that's good.
我现在可以得到按键的类型了，不错
963
00:47:54,672 --> 00:47:58,741
Current title, the current title displayed on the button,
“Current title”，按键上的名称
964
00:47:58,743 --> 00:48:00,643
victory, that's what we want. Okay,
胜利了！这就是我们要的，okay？
965
00:48:00,645 --> 00:48:03,012
now when we find something in the documentation we want,
现在，当我们需要在文档中找东西时
966
00:48:03,014 --> 00:48:06,115
you're gonna see that there is a Swift explanation
你可以看见这里有关于swift解释
967
00:48:06,117 --> 00:48:08,918
of it, and and objective C explanation. So we're always
或者关于 Objective C 的解释
968
00:48:08,920 --> 00:48:12,021
going to be looking at the Swift version in this class.
我们看看这个类的解释的 swift 版本
969
00:48:12,357 --> 00:48:13,322
So what is this thing, okay?
这是个什么？
970
00:48:13,324 --> 00:48:16,926
This is not a method because it would say func right here.
它不是一个方法，因为方法前面有一个 “func”
971
00:48:16,928 --> 00:48:19,595
If this were a method on UIButton you would have func.
如果它是 UIButton 里的方法，你会看到一个 ”func”
972
00:48:19,597 --> 00:48:22,265
Instead it has var, that means it's a property.
但这有一个 “var”，意味着它是一个属性
973
00:48:22,267 --> 00:48:25,034
So a property's like an instance variable, okay?
属性就像一个实例变量，okay？
974
00:48:25,036 --> 00:48:27,436
Now this is an interesting property because it's got this
这是个有趣的属性
975
00:48:27,438 --> 00:48:31,908
little terminology on the end, which means it's read only. So
因为在末尾有个这个东西，意味着它是只读的
976
00:48:31,910 --> 00:48:34,877
we can't set the button's title here with current title.
所以我们不能通过它来设置这个按键的名称
977
00:48:34,879 --> 00:48:37,413
Turns out that's because there's another method up here
但是呢还有一个方法
978
00:48:37,415 --> 00:48:40,750
called setTitle forState for setting the button's title.
叫 “setTitle forState“ 来设置按键的名称
979
00:48:40,752 --> 00:48:41,884
Because when you set the button's title,
因为当你设置一个按键名称的时候
980
00:48:41,886 --> 00:48:44,320
you wanna set the title for what state it's in,
你需要知道这个按键的状态
981
00:48:44,322 --> 00:48:46,589
highlighted, disabled, whatever. But luckily there's
高亮？禁用？无所谓
982
00:48:46,591 --> 00:48:50,493
a current title here that just gets you the current title.
幸运的是这里有一个 “current title” 让你获取当前按键名称
983
00:48:50,862 --> 00:48:52,995
In whatever state the button is currently in.
不管这个按键当前是什么状态的
984
00:48:52,997 --> 00:48:55,998
So, here is, so that's why it says var instead of func.
这就是这为什么是 var 而不是 func
985
00:48:56,000 --> 00:48:59,635
Here's the name of the property, currentTitle.
这里是属性的名字，currentTitle
986
00:48:59,637 --> 00:49:00,436
Here is the type.
这里是它的类型
987
00:49:00,438 --> 00:49:03,906
I promised you that it was always colon and type. Now,
我向你保证类型前总是有一个冒号
988
00:49:03,908 --> 00:49:09,011
the type of this is string? >> [LAUGH]
现在这个类型是 String??
989
00:49:09,013 --> 00:49:11,614
>> Wha? Maybe. Okay? We're
啥？可能是吧，okay
990
00:49:11,616 --> 00:49:14,984
gonna suspend our disbelief here because that question
现在刹住你们的疑问，因为这个问号
991
00:49:14,986 --> 00:49:18,721
mark actually means something. We're gonna kinda hope that
意味着些什么，我们希望这是一个 string
992
00:49:18,723 --> 00:49:22,158
this is a string, but it's not going to be. But that's okay.
但它不是，不过没有关系
993
00:49:22,160 --> 00:49:24,860
So we're gonna try and assume it is. All right? So anyway,
我们就假设它是，好吗？
994
00:49:24,862 --> 00:49:26,495
this is how we look things up in the documentation
无论如何，这就在文档里如何找东西的办法
995
00:49:26,497 --> 00:49:30,199
to see the way it works. Now, there's another way to do it,
现在，也有其他办法来做这事
996
00:49:30,201 --> 00:49:32,468
okay, which is even cooler. I type this dot.
更酷一点，我输入这个”.”
997
00:49:32,470 --> 00:49:35,538
I want the title so I'm just going to start typing title.
我想使用”title”，所以我就继续输入”title”
998
00:49:35,540 --> 00:49:37,840
Okay I don't know there is a method called title,
okay，我不知道这里是否有一个方法，名字是title
999
00:49:37,842 --> 00:49:40,843
in fact there isn't. But as soon as I started typing title
事实上是没有的，但只要我输入完之后
1000
00:49:40,845 --> 00:49:43,346
it shows me all the methods that start with title.
它会告诉我所有以 “title” 开头的方法的名字
1001
00:49:43,348 --> 00:49:48,617
All the methods that include title in the name. See?
所有名字里包含了 title 的方法，看见了吗？
1002
00:49:48,753 --> 00:49:54,156
And all the methods that have T-I-T-L-E in the order. Okay,
还有所有含有 T-I-T-L-E 这个字母顺序的方法
1003
00:49:54,158 --> 00:49:57,093
and it gives it to you in the order you might expect right?
这会按照你期望的顺序呈现
1004
00:49:57,095 --> 00:50:00,363
Title first and then. So this is kinda helping,
含有 title 这个词的优先，别的在后面，这提供了一种帮助
1005
00:50:00,365 --> 00:50:00,997
you can search basically.
你可以这么搜索
1006
00:50:00,999 --> 00:50:03,599
And when you do this you would quickly see current title,
当你这么做的时候，你快速浏览到 currentTitle
1007
00:50:03,601 --> 00:50:06,769
that looks like what I want. And you can double click here,
这看起来像是我想要的。你就在这双击
1008
00:50:06,771 --> 00:50:09,138
actually, and it will put in there. Okay? So
这样就会出现在这里。
1009
00:50:09,140 --> 00:50:12,942
there's our current title. Now instead of printing touch
这就是我们要的 currentTitle
1010
00:50:12,944 --> 00:50:17,313
digit we basically wanna print which one, which digit was,
现在我们想打印具体按到的某个数字，而不是 touchDigit
1011
00:50:17,315 --> 00:50:22,485
touched here. So I'm gonna say touched, we could say percent,
所以这里要换成
1012
00:50:22,487 --> 00:50:25,254
s digit. Comma digit.
“touched %s digit”, digit
1013
00:50:25,256 --> 00:50:27,790
This is what it would look like in C. For example,
这就看起来像是C语言
1014
00:50:27,792 --> 00:50:31,327
is everyone familiar with this print F like format?
所以你们对 printf 熟悉吗
1015
00:50:31,329 --> 00:50:33,696
Okay good, cuz you can't do it in Swift.
很好，但你不能在 Swift 里这样做
1016
00:50:33,698 --> 00:50:34,096
Okay. >> [LAUGH]
1017
00:50:34,098 --> 00:50:35,164
>> We don't do that in Swift.
我们在 Swift 里不这么做
1018
00:50:35,166 --> 00:50:37,633
Instead, we do backslash, open parentheses,
我们用反斜杠、括号代替
1019
00:50:37,635 --> 00:50:40,903
close parentheses. And then we can put anything we want in
然后里面放任何我们想放的
1020
00:50:40,905 --> 00:50:43,806
here. Okay clean digit. And we don't need this out here on
删掉 digit，引号外不需要它
1021
00:50:43,808 --> 00:50:47,510
the side. Okay, so this will be invaluated converted to
所以这会被转换成 string 类型
1022
00:50:47,512 --> 00:50:50,279
a string. Some things can't be converted to strings but
有的不能被转换，但大多数可以
1023
00:50:50,281 --> 00:50:53,215
most things can, so you put that in there. Okay,
所以你可以把它放在里面
1024
00:50:53,217 --> 00:50:56,652
if you can't you'll get a warning, okay? All right, so
如果不可以，你会被警告
1025
00:50:56,654 --> 00:50:58,054
that's how we do that. So, let's go ahead and
所以我们就这么做了
1026
00:50:58,056 --> 00:51:01,357
see what's going on. But now maybe we should start paying
继续看看接下来会发生什么
1027
00:51:01,359 --> 00:51:02,024
attention to our warnings.
我想现在应该开始注意一下这个警告了
1028
00:51:02,026 --> 00:51:05,428
Okay, when you submit your homework, no warnings please.
当你们交作业的时候，不准有警告
1029
00:51:05,430 --> 00:51:07,463
Okay, no warnings. And certainly no errors,
没有警告，当然也不能有错误
1030
00:51:07,465 --> 00:51:10,433
those are red things those won't build, no warnings. So
有错误的时候就不能 build
1031
00:51:10,435 --> 00:51:12,535
what is this warning, let's take a look at this warning.
这个警告是什么呢？我们来看看
1032
00:51:12,537 --> 00:51:14,170
You look at a warning by clicking on it.
我们通过点击来看一个警告
1033
00:51:14,172 --> 00:51:16,572
So I'm gonna click on it, and it says here,
我点击他，这里是这么写的
1034
00:51:16,574 --> 00:51:21,644
variable digit with never mutated, consider changing to
digit 这个变量没有被改变过
1035
00:51:21,646 --> 00:51:26,082
let constant. Okay, what does that mean?
是不是考虑把他变成 let 型常量。这是什么意思呢？
1036
00:51:26,084 --> 00:51:31,020
That means that instead of var here, it wants us to put let.
这里的意思是，希望我们用 let 而不是 var
1037
00:51:31,022 --> 00:51:34,623
And in fact, you should always do that. Anytime you declare
事实上我们应该这么做
1038
00:51:34,625 --> 00:51:37,793
a local variable, okay, or even a property that is
任何时候申明一个局部变量，或者一个属性
1039
00:51:37,795 --> 00:51:40,629
initialized at the beginning and never changes, in other
在初始化后就一直没被改变，换句话说，
1040
00:51:40,631 --> 00:51:43,599
words, it's a constant, use let instead of var.
就是个常量，我们就应该用 let 而不是 var
1041
00:51:43,601 --> 00:51:46,268
Now why do you want to do that? Two reasons really, one,
那么我们现在为什么要这么做？两个理由
1042
00:51:46,270 --> 00:51:48,804
it helps people reading your code realize this thing's
一、这帮助别人读你的代码的时候意识到
1043
00:51:48,806 --> 00:51:51,040
never going to change, I don't have to worry about it,
这个一直不会变，不需要去担心它
1044
00:51:51,042 --> 00:51:54,243
it's just like a constant. And two, if that thing were for
这只是个常量。二、如果那个东西，
1045
00:51:54,245 --> 00:51:57,613
example, an array, or a dictionary, and you use let,
比如说是一个数组或者字典，你用了 let
1046
00:51:57,615 --> 00:52:00,883
that means nothing can be put into that dictionary or
这就意味着没有什么可以放进字典或从字典拿出
1047
00:52:00,885 --> 00:52:04,553
taken out. Or into the array or taken out okay. So
也可以放进数组或从数组拿出
1048
00:52:04,555 --> 00:52:08,023
it's how you can create read only arrays and dictionaries
这就是你如何创建只读的数组或者是字典
1049
00:52:08,025 --> 00:52:12,628
okay. So, always use let when you are doing a constant.
所以申明常量的时候一定记得用 let
1050
00:52:12,630 --> 00:52:14,563
And in fact notice that XCode is saying,
注意 Xcode 这里说的
1051
00:52:14,565 --> 00:52:17,733
hey if you click here I'll fix it for you. Okay,
如果你点这里，我会为你修复这个问题
1052
00:52:17,735 --> 00:52:21,904
see how it says fix it replays var with let. Sure. Okay, and
看一下它如何用 let 代替 var 修正这个问题
1053
00:52:21,906 --> 00:52:24,773
it did it and now the warnings gone. Okay, so
所以它做到了，警告没了
1054
00:52:24,775 --> 00:52:29,678
let's run, see if this is working. We're crossing our
来跑一下，看看是不是能行
1055
00:52:29,680 --> 00:52:32,915
fingers about that whole string question mark thing.
我们越过我们的手指关于整串问号的事情
1056
00:52:32,917 --> 00:52:35,518
All right, so here we go, let's press 5.
好了，来按下 5
1057
00:52:36,921 --> 00:52:40,189
The heck is going on down there? Okay, touched
这下面就会显示数字
1058
00:52:40,191 --> 00:52:45,294
optional 5 digit? Okay so what is this optional business.
touched optional("5") digit？这里的 optional 是什么
1059
00:52:45,296 --> 00:52:47,163
Here you all wanna take a deep breath,
所以这里你们得深呼吸
1060
00:52:47,165 --> 00:52:50,332
clear your minds, and pay close attention okay. Because
清空你们的脑袋，集中全部注意力
1061
00:52:50,334 --> 00:52:52,935
this is a very important thing in Swift, it's ubiquitous
因为这是 Swift 里非常非常重要的东西
1062
00:52:52,937 --> 00:52:57,740
throughout the entire iOS API okay. Very cool feature, but
这在 iOS API 里无处不在，一个非常酷的特性
1063
00:52:57,742 --> 00:53:00,442
it requires a little bit of getting used to in terms of
但是需要一段时间来熟悉这个语法
1064
00:53:00,444 --> 00:53:05,381
its syntax okay? This is the feature of optionals. Okay?
这是一个叫 optional（可选类型）的特性
1065
00:53:05,383 --> 00:53:09,818
In Swift, there is a type called optional.
在Swift里，有一种类型叫 optional
1066
00:53:09,820 --> 00:53:12,388
It's a type like int or boolean or anything else,
这是一种类似于 int 或 bool 的类型
1067
00:53:12,390 --> 00:53:14,323
string, it's dictionary, array,
或者是 string、dictionary、array 这样的类型
1068
00:53:14,325 --> 00:53:18,360
optional. Optional is just a type. This type can only have
optional 只是一个类型，这个类型只有两个值
1069
00:53:18,362 --> 00:53:23,699
two values. One value is not set. Okay?
一个值是没有被赋值
1070
00:53:23,701 --> 00:53:28,070
That's expressed in Swift with the key word nil, N-I-L.
在 Swift 里表示它的关键字是 nil
1071
00:53:28,072 --> 00:53:31,473
Nil only means, this optional is not set.
nil 只表示这个 optional 没有被赋值
1072
00:53:31,475 --> 00:53:33,709
That's all it means in Swift. It doesn't mean zero.
这就是他在 Swift 里全部的含义，这不代表它为零
1073
00:53:33,711 --> 00:53:36,245
It doesn't mean a pointer that doesn't point anywhere, like
这不像别的语言，它不代表一个不指向任何地方的指针
1074
00:53:36,247 --> 00:53:39,882
in other languages. Nil means an optional that's not set.
nil 代表一个 optional 没有被赋值
1075
00:53:39,884 --> 00:53:45,120
The other state that an optional can be is set,
另一个状态就是一个 optional 被赋值了
1076
00:53:45,122 --> 00:53:48,691
okay? Now, if it's in the set state, it can have
如果它在被赋值状态
1077
00:53:48,693 --> 00:53:52,995
an associated value, okay? An associated value,
他就可以有一个关联值
1078
00:53:52,997 --> 00:53:55,698
which can be of any other type, okay? Actually it also
一个可以是其他任何类型的关联值
1079
00:53:55,700 --> 00:53:57,199
could also be an optional. You can have an optional,
实际上，它还可以是一个 optional 。你可以有一个 optional
1080
00:53:57,201 --> 00:54:00,970
optional, but that associated value is just associated with
但是关联值只和它赋值的状态关联
1081
00:54:00,972 --> 00:54:03,405
this set state, okay? In the not set state,
在未赋值状态
1082
00:54:03,407 --> 00:54:06,375
there is no associated value cuz it's not set. Okay?
它就没有关联值，因为它没有被赋值
1083
00:54:06,377 --> 00:54:09,011
Now what does it look like to declare it optional? Well,
那么把它申明为 optional 看起来是什么样呢？
1084
00:54:09,013 --> 00:54:12,615
let's go back with our option key and take a look at current
让我们回过头看一下我们的 option 键看一下 currentTitle
1085
00:54:12,617 --> 00:54:15,017
title. Okay, you remember this from the documentation?
还记得这段文档吗？
1086
00:54:15,019 --> 00:54:20,289
It says var currentTitle string? That means this is
这里写到 "var currentTitle: string?"
1087
00:54:20,291 --> 00:54:25,694
an optional whose associated value is a string. Okay?
这里的意思是这是个关联值为 string 的 optional
1088
00:54:25,696 --> 00:54:28,063
So if someone looks at this property and
所以如果有人看到这个属性
1089
00:54:28,065 --> 00:54:29,198
says, what type is that property?
当他问这个是什么类型的时候
1090
00:54:29,200 --> 00:54:32,701
And they say, it's a string but it's optional no, no.
他可能会说，这是个 string，但是是 optional。不！
1091
00:54:32,703 --> 00:54:37,973
This is an optional and it's associated values of string,
这是个 optional，他的关联值是 string
1092
00:54:37,975 --> 00:54:42,311
okay? Get used to saying, this type is optional, okay? So
要习惯于说这个类型是 optional
1093
00:54:42,313 --> 00:54:45,114
this is an optional string, that's what would say.
这是个 optional string（可选字符串），这才是正确的
1094
00:54:45,116 --> 00:54:47,516
It's an optional string, okay? But primarily,
这是个 optional string。主要是个 optional
1095
00:54:47,518 --> 00:54:51,053
it's an optional. Okay, it's associated value is a string.
关联值是 string
1096
00:54:51,055 --> 00:54:53,922
So this currentTitle, why is it an optional? Well,
所以这个 currentTitle 为什么是个 optional?
1097
00:54:53,924 --> 00:54:58,560
because we might have a button here that has no title set.
这是因为一个按钮的标题可能不会被赋值
1098
00:54:58,562 --> 00:55:02,064
Not set. Okay, so the title needs to be an optional,
没有赋值，所以它应该是个 optional
1099
00:55:02,066 --> 00:55:05,367
so it can represent the case where it's not set. Now,
所以它就可以表示没有被赋值的情况
1100
00:55:05,369 --> 00:55:08,304
anything can be an optional. Not just pointers, or objects.
所以任何东西都可以是 optional。不只是指针或对象
1101
00:55:08,306 --> 00:55:11,440
Ints could be optional. You could have an optional int,
int 可以是 optional，你可以有一个 optional int
1102
00:55:11,442 --> 00:55:15,077
okay? But here we are representing the title,
但这里我们代表了一个标题
1103
00:55:15,079 --> 00:55:18,414
the button, which is the string and it might be not set
这个按钮的标题是个 string，这可能不会被赋值
1104
00:55:18,416 --> 00:55:20,382
okay? So we need that to be an optional.
我们需要这个是个 optional
1105
00:55:20,384 --> 00:55:23,519
So how do I get the string, because I don't want
所以我怎么得到这个 string
1106
00:55:23,521 --> 00:55:27,690
this digit, which currently is also an optional string?
我不希望这个 digit，现在还是个 optional string
1107
00:55:27,692 --> 00:55:30,559
Isn't it kinda weird here when I said let digit equal,
当这里是 "let digit ＝" 的时候不是很奇怪吗
1108
00:55:30,561 --> 00:55:34,029
nobody said how come you didn't say colon string?
没人觉得你为什么不加上 ":string" 呢？
1109
00:55:34,031 --> 00:55:37,900
Okay? I didn't say the type. I declared a local variable.
我没有说类型，我申明一个局部变量
1110
00:55:37,902 --> 00:55:41,170
It didn't even have a type. How was that possible?
我甚至都没有一个类型，这怎么可能？
1111
00:55:41,172 --> 00:55:46,742
In Swift, Swift will infer the type all the time, okay? If
在 Swift 里，Swift 会一直推断类型
1112
00:55:46,744 --> 00:55:49,411
it's possible for it to know the type it will infer it.
如果它可以在这里知道他的类型，那么就会推断这个类型
1113
00:55:49,413 --> 00:55:54,183
And in fact it's wrong really bad coding style to put that
实际上，这里写上类型是个非常差的编程风格
1114
00:55:54,185 --> 00:55:58,220
type in there. It's better to just say let digit equal and
这里最好就这么写
1115
00:55:58,222 --> 00:56:01,190
let swift infer it. And here Swift has inferred.
让 Swift 来推断他的类型。这里 Swift 也做到了
1116
00:56:01,192 --> 00:56:03,325
The digit must be of type string question mark,
这里的 digit 一定会是个 "string?" 类型
1117
00:56:03,327 --> 00:56:06,228
that's because this is of type string question mark.
因为后面的也是个 "string?" 类型
1118
00:56:06,230 --> 00:56:09,365
So of course digit has to be that. You see what's happening
所以 digit 当然也应该是那个类型。你看到那发生什么了吗？
1119
00:56:09,367 --> 00:56:12,668
there? So you're going to see type inference all the time in
Swift 里你会时时看到类型推断的结果
1120
00:56:12,670 --> 00:56:14,203
Swift, it makes your code much more compact,
这让你代码更加简洁
1121
00:56:14,205 --> 00:56:18,374
a lot less repeated stuff, is that a question in the back?
很多更少重复的工作，那边的同学有问题吗？
1122
00:56:18,376 --> 00:56:19,875
>> Yeah, is that the same for
这对 var 是一样的吗？
1123
00:56:19,877 --> 00:56:20,209
var too. >> Is the question is
问题是：
1124
00:56:20,211 --> 00:56:22,277
that same for var too, absolutely it's the same for
这对 var 是一样的吗？
1125
00:56:22,279 --> 00:56:26,382
var, okay? So, how do I get that string though?
完全一样。所以我怎么获得那个 string 呢？
1126
00:56:26,384 --> 00:56:28,951
If this button title is set, how do I get that
如果这个按钮的标题已经有了，那我如何
1127
00:56:28,953 --> 00:56:32,721
associated value thing, okay, out of this optional?
从这个 optional 里面获取这个关联值？
1128
00:56:32,723 --> 00:56:36,525
And the answer is you put an exclamation point in the end,
方法是你在最后放一个感叹号
1129
00:56:36,527 --> 00:56:39,328
okay. Now, optional is question mark on the end of
optional 在定义的末尾有个问号
1130
00:56:39,330 --> 00:56:42,831
a declaration. Exclamation point is unwrap this thing and
感叹号是用来 unwarp（解包）这个 optional
1131
00:56:42,833 --> 00:56:46,402
give me the associative value. So this is very succinct,
然后给我这个关联值。这是很简明的
1132
00:56:46,404 --> 00:56:50,038
one character for each side of you using this, okay?
每次可以使用一种符号
1133
00:56:50,040 --> 00:56:51,774
Question. >> Can you briefly talk about
学生问题：
1134
00:56:51,776 --> 00:56:52,074
why you want the title to,
1135
00:56:52,076 --> 00:56:53,976
why you design the title to be optional instead of like
1136
00:56:53,978 --> 00:56:59,114
an empty string? >> Okay, so the question is,
问题是
1137
00:56:59,116 --> 00:57:02,384
why does Swift have this optional thing instead of just
为什么 Swift 不直接用空字符
1138
00:57:02,386 --> 00:57:05,120
doing empty string to mean a button without a title?
而是用 optional 来表示一个没有标题的 button？
1139
00:57:05,122 --> 00:57:10,492
Or maybe for an int minus 1. I don't know. Or for a point or
或者是一个 -1 的 int
1140
00:57:10,494 --> 00:57:14,463
0 memory address or something like that. The main reason for
又或者是一个指针、一个不占内存的地址或者类似的什么东西
1141
00:57:14,465 --> 00:57:18,100
that is for example, pointers to objects in Swift, you don't
这主要的原因是，Swift 里的指针
1142
00:57:18,102 --> 00:57:21,703
see the memory address. So you couldn't have it be 0, okay,
你是看不见内存地址的。所以你不能让他为 0
1143
00:57:21,705 --> 00:57:23,906
that's hidden from you. So there'd be no way to do it.
这对你是隐藏的。所以没法这样做
1144
00:57:23,908 --> 00:57:28,076
For an int, if you wanted an optional int, is it minus 1 or
对于 int，如果你想要一个 optional int
1145
00:57:28,078 --> 00:57:31,280
0, max int? What is it, it don't know what it is.
它到底是 -1？是 0？还是别的什么？他不知道应该是多少。
1146
00:57:31,282 --> 00:57:34,817
So Swift is trying to be consistent across all things.
所以Swift 想涵盖所有情况
1147
00:57:34,819 --> 00:57:38,854
Ints, pointers to objects, whatever to make sure that
Ints ，指向对象的指针
1148
00:57:38,856 --> 00:57:40,456
we can tell which ones are not set. Okay, so
无论是什么，要保证我们能知道他有没有被赋值
1149
00:57:40,458 --> 00:57:42,591
that's the thought behind it. It's really great actually,
这就是 optional 背后的思考，非常棒
1150
00:57:42,593 --> 00:57:46,094
once you get used to it it's fantastic. All right, so
一旦你习惯这种做法，真的非常赞
1151
00:57:46,096 --> 00:57:47,830
we unwrap it with this exclamation point.
我们用感叹号对它进行 unwarp
1152
00:57:47,832 --> 00:57:51,767
Now what would happen if that current title value was
如果这里的 currentTitle 没有被赋值，会发生什么？
1153
00:57:51,769 --> 00:57:54,903
not set? And this exclamation point tried to pull out
这个感叹号试着去把值取出来
1154
00:57:54,905 --> 00:57:57,873
the associated value? What do you think would happen?
你觉得会发生什么
1155
00:57:57,875 --> 00:57:58,674
>> Error.
错误
1156
00:57:58,676 --> 00:58:00,576
>> Error, yeah, bad error.
错误，是的大错特错
1157
00:58:00,578 --> 00:58:02,644
It would crash my app, okay? So
这会让你的应用崩溃
1158
00:58:02,646 --> 00:58:05,247
exclamation point crashes your app if you tried to
如果你试着 unwarp 一个没有被赋值的 optional
1159
00:58:05,249 --> 00:58:08,750
unwrap an optional that's in the not set state, okay,
感叹号会让你的应用崩溃
1160
00:58:08,752 --> 00:58:12,921
if it's nil. Now some of you conservative folks might be
如果它为空。有些保守的人会说
1161
00:58:12,923 --> 00:58:15,257
saying I'm never using exclamation point, that's so
他从来不用感叹号
1162
00:58:15,259 --> 00:58:18,927
easy to crash my app. Okay? And the answer to that is yes
因为太容易让应用崩溃。但答案是
1163
00:58:18,929 --> 00:58:22,498
it is, but sometimes crashing your app is a good thing.
是的，确实容易让应用崩溃，但有时候这是好事
1164
00:58:22,500 --> 00:58:23,999
It helps you find a bug, okay?
这会帮助你找到 bug
1165
00:58:24,001 --> 00:58:26,869
Because something that you expect to be set by a certain
因为有的时候你希望他被赋予一个确定的值
1166
00:58:26,871 --> 00:58:28,737
point isn't, and it crashes your app, and
如果没有，那就让应用崩溃
1167
00:58:28,739 --> 00:58:31,206
you find it before it goes out to your customer. And some
你在 app 发布给你的用户之前就找到这个 bug
1168
00:58:31,208 --> 00:58:33,842
unexpected thing is happening because something's not set.
因为有些没被赋值，会发生一些预期之外的事情
1169
00:58:33,844 --> 00:58:36,311
Now, I'm gonna show you a little later how you can
我稍后会给你们展示
1170
00:58:36,313 --> 00:58:38,046
unwrap the optional and get the associated value
如何不让应用崩溃的情况下 unwarp optional 并获取关联值
1171
00:58:38,048 --> 00:58:41,250
without crashing. Basically, test to see if it's set and
总的来说，自测一下它有没有被赋值
1172
00:58:41,252 --> 00:58:44,286
do it, okay? So I'm gonna show you that in a little bit.
我过一会会做给你们看
1173
00:58:44,421 --> 00:58:45,954
All right, so we've unwrapped this, optional.
我们已经 unwarp 了这个 optional
1174
00:58:45,956 --> 00:58:49,224
We're gonna crash if it's not set, that's fine. And so
如果没有被赋值会让应用崩溃，这没问题
1175
00:58:49,226 --> 00:58:52,661
now, notice when I do the option click on digit,
注意我按住 option 键 然后点这个 digit
1176
00:58:52,663 --> 00:58:57,299
what's the type? String, not optional string,
什么类型呢？不是 optional string
1177
00:58:57,301 --> 00:59:00,569
string, that's good because we unwrapped it. So now when we
就是 string，这很棒，因为我们 unwarp 了
1178
00:59:00,571 --> 00:59:05,240
run, instead of saying touched optional 6 digit down there,
现在跑一下，就不会说 "touched optional 6 digit" 了
1179
00:59:05,242 --> 00:59:10,579
it's going to say touch the 6 digit, touch 2, touch 4, 8, 9,
而是说 "touch the 6 digit" 或者 "touch 2、4、8、9"
1180
00:59:10,581 --> 00:59:17,019
okay? Got it? Okay, now, this is going good, but we
明白了吗？这很棒
1181
00:59:17,021 --> 00:59:21,123
don't really want this to be printing out in the console.
但我们不想它在控制台打印出来
1182
00:59:21,125 --> 00:59:23,725
We want our calculator to have a display and
我们希望我们的计算器有个显示
1183
00:59:23,727 --> 00:59:26,762
we want the digits we typed to go in the display, right. So
我们希望我们按下的 digits 能显示出来
1184
00:59:26,764 --> 00:59:29,665
let's go do that. Let's add a display to our
所以现在来做这个。加一个显示
1185
00:59:29,667 --> 00:59:32,534
user interface here. We're gonna put it at the top, okay?
到 UI 上。我们会把这个放在顶部
1186
00:59:32,536 --> 00:59:35,537
I'm talking about this thing right up here where this 0 is.
我指的是这个右上角零的这个
1187
00:59:35,539 --> 00:59:37,439
And I wanna it to kinda look similar to that,
我希望看起来很像这个
1188
00:59:37,441 --> 00:59:39,241
maybe some different colors but kinda like that.
可能是不同颜色，但是类似吧
1189
00:59:39,243 --> 00:59:44,479
So I'm gonna go back to my utilities area over here and
现在回到组件的区域
1190
00:59:44,481 --> 00:59:45,547
go to the bottom. And this time,
到最底部，这次
1191
00:59:45,549 --> 00:59:48,617
instead of grabbing a button, I'm gonna grab one of these,
不是抓一个 button，而是抓一个这个
1192
00:59:48,619 --> 00:59:52,921
a label. So a label is Read only text,
一个 label，label 是一个只读的文本
1193
00:59:52,923 --> 00:59:55,691
okay? The user can't touch on it, and then type
用户不能碰这个
1194
00:59:55,693 --> 00:59:58,527
with the little keyboard on the iPhone, okay? This is read
然后用键盘输入
1195
00:59:58,529 --> 01:00:01,229
only text which is what we want on my calculator. So
这是一个我们计算器上需要的只读的文本
1196
01:00:01,231 --> 01:00:04,099
I'm gonna bring it over here, bring it out, again same way
我会让它到这里，拖出来
1197
01:00:04,101 --> 01:00:08,503
as before. I can resize it, I can change what's in there,
跟之前一样，我可以重新定义它的大小
1198
01:00:08,505 --> 01:00:11,273
I can change the font over here. Let's make this one
可以改变文字。现在让它字变大
1199
01:00:11,275 --> 01:00:15,978
really big, how about 40 point. I can even make it
差不多 40pt 吧。我还可以让它右对齐
1200
01:00:15,980 --> 01:00:18,747
right aligned, you know how in calculators usually
你知道一般计算器都是右对齐
1201
01:00:18,749 --> 01:00:21,316
the text is on the right so there's an alignment thing for
这里有个 label 对齐选项
1202
01:00:21,318 --> 01:00:23,952
the label here, so we'll do that. Maybe I want to change
我们可以这么做。
1203
01:00:23,954 --> 01:00:27,189
the background color for this one too, how about blue, okay
我也想换一下背景颜色，蓝色就不错
1204
01:00:27,191 --> 01:00:30,158
there's blue. I don't really like black on blue, here's
但我不喜欢蓝底黑字
1205
01:00:30,160 --> 01:00:33,829
a color of the text, we'll go white on blue. Okay, so
这里是文字颜色，蓝底白字就挺好
1206
01:00:33,831 --> 01:00:37,099
I can basically set it however I want, okay, got this UI,
我可以随意设置这些
1207
01:00:37,101 --> 01:00:39,001
I could use the blue lines by the way,
也可以用蓝线辅助
1208
01:00:39,003 --> 01:00:43,405
to line it up nicely here, but again not so important because
这样就可以很整齐的放置
1209
01:00:43,407 --> 01:00:46,742
I'm going to do the flexible UI thing on Wednesday, but
不是特别重要的是，我会在周三教自适应的 UI 布局
1210
01:00:46,744 --> 01:00:51,780
I could do it. All right, so now, how about connecting this
我可以做这些。
1211
01:00:51,782 --> 01:00:55,050
to our controller? This is a little different because this
那么如何把这个 label 跟 controller 联系起来？
1212
01:00:55,052 --> 01:00:58,220
is not a case where the user's gonna touch this thing and
这有点不太一样，因为这不是那种用户点一下
1213
01:00:58,222 --> 01:00:58,887
it's gonna invoke a method.
就调用一个方法的情况
1214
01:00:58,889 --> 01:01:02,524
It's more the other way around. I wanna talk to it.
这是另外一种情况，我想跟它交互
1215
01:01:02,526 --> 01:01:04,359
Okay, I wanna put things in the display.
我想把东西放进去展示
1216
01:01:04,361 --> 01:01:07,863
So this is communication coming from the controller to
这是一个从 controller 到显示的通信
1217
01:01:07,865 --> 01:01:11,500
the display instead of from a button to the controller. So
而不是一个按钮到 controller 的通信
1218
01:01:11,502 --> 01:01:15,771
we still connect them up in the same way using control and
我们还是一样用按住 control 拖拽的方式
1219
01:01:15,773 --> 01:01:20,275
drag, okay, to put something into our controller. But
把一些东西放进 controller
1220
01:01:20,277 --> 01:01:24,179
this time instead of action up here we're going to do outlet.
但这次我们选 outlet 而不是 action
1221
01:01:24,181 --> 01:01:27,149
And what outlet means is instead of creating a method,
outlet 的意思是新建一个属性
1222
01:01:27,151 --> 01:01:30,285
create a property. Right? An instance variable,
而不是方法。一个实例变量
1223
01:01:30,287 --> 01:01:32,721
just like currentTitle is an instance variable, or
就像 currentTitle 是一个实例变量
1224
01:01:32,723 --> 01:01:34,256
property, we're gonna have a property here.
或者一个属性，这里我们有了一个属性
1225
01:01:34,258 --> 01:01:36,992
And this property is going to point to this display for
这个属性会指向显示屏
1226
01:01:36,994 --> 01:01:39,628
us so we can access it any time we want. So
这样我们就可以在任何需要的时候获取它
1227
01:01:39,630 --> 01:01:44,299
I'm gonna call this property display, not that, display,
我准备叫这个属性 display
1228
01:01:44,301 --> 01:01:47,469
okay? Luckily it got the type right here, it didn't say any
碰巧这里有类型，这没说有任何对象
1229
01:01:47,471 --> 01:01:50,338
objects. It's good, it knows it was a UI label. And don't
这很好，它知道是个 UILabel
1230
01:01:50,340 --> 01:01:52,974
worry about this storage, weak or strong, we'll talk about
也不用担心这个 storage 是 strong 或是 weak
1231
01:01:52,976 --> 01:01:55,043
that next week, so you can just ignore that for now.
我们下周再说，所以你现在就可以忽略他
1232
01:01:55,045 --> 01:01:58,213
Okay, so I hit connect and it creates,
我点击 connect，它就被创建了
1233
01:01:58,215 --> 01:02:02,250
instead of creating a method here, it created a property.
这里创建了一个属性而不是一个方法
1234
01:02:02,252 --> 01:02:06,722
Now again, this IB outlet is just something that Xcode puts,
再一次，这个 IBOutlet 只是 Xcode 放这的。
1235
01:02:06,724 --> 01:02:07,989
put this little circle here. So
放了一个小圆圈在这里
1236
01:02:07,991 --> 01:02:11,159
we can see what it's connected to, so you can ignore that.
我们可以看到这个链接到了什么，所以你可以忽略那个
1237
01:02:11,161 --> 01:02:12,060
I told you to ignore weak and
我说了可以忽略 weak 和 strong
1238
01:02:12,062 --> 01:02:14,730
strong, so you can ignore that. And so hopefully
所以可以忽略它
1239
01:02:14,732 --> 01:02:18,533
this is familiar to you, it looks like current title, var.
这个看起来很熟悉，有点像 currentTitle
1240
01:02:18,535 --> 01:02:21,636
This is a property on our controller. Okay,
这是你 controller 里的一个属性
1241
01:02:21,638 --> 01:02:24,005
an instance variable, if you wanna think of it that way.
一个实例变量，如果你想这么认为的话
1242
01:02:24,007 --> 01:02:29,544
It's called display. Its type is UI label exclamation point.
这叫 display。类型是 UILabel!
1243
01:02:29,546 --> 01:02:33,648
Okay, now what the heck is that, exclamation point? Okay,
这里的感叹号又是什么意思呢？
1244
01:02:33,650 --> 01:02:35,784
I thought exclamation point was unwrapping optionals,
我认为感叹号是用来 unwrapping optional 的
1245
01:02:35,786 --> 01:02:38,153
why is there an exclamation point here, it makes no sense.
这里为什么有个感叹号？这不科学。
1246
01:02:38,155 --> 01:02:42,424
And in fact you can put a question mark here because
事实上你可以在这里放个问号
1247
01:02:42,426 --> 01:02:44,860
exclamation point also means optional.
因为感叹号也代表了 optional
1248
01:02:44,862 --> 01:02:47,329
It means the same kinda optional as question mark.
这跟问号表示的 optional 是一个意思
1249
01:02:47,331 --> 01:02:48,830
And I'm gonna leave this question mark, and
我会先在这放一个问号
1250
01:02:48,832 --> 01:02:50,599
I'm gonna keep working on this demo, and
继续完成这个 demo
1251
01:02:50,601 --> 01:02:51,099
then I'm gonna go back and
然后回过头来
1252
01:02:51,101 --> 01:02:52,167
change it to an exclamation point, and
把它改成感叹号
1253
01:02:52,169 --> 01:02:55,604
show you what exclamation point means. Okay? But
告诉你们感叹号是什么意思。
1254
01:02:55,606 --> 01:02:58,073
exclamation point and question mark both mean optional,
当你定义的时候，
1255
01:02:58,075 --> 01:03:02,744
when you're declaring. Okay, so now I have this display.
感叹号和问号都表示 optional。所以现在你有了这个 display
1256
01:03:02,746 --> 01:03:06,515
When numbers get touched here, I want to, basically, append
当数字被按下的时候，我想
1257
01:03:06,517 --> 01:03:09,684
these digits onto whatever's already in the display,
不管显示了什么都把 digit 加到 display 上
1258
01:03:09,686 --> 01:03:12,287
all right? So let's go ahead and do that.
所以现在来做这个
1259
01:03:12,289 --> 01:03:14,556
We can get rid of this print to the console.
删掉这个打印到控制台的
1260
01:03:14,558 --> 01:03:16,658
We don't need to do that anymore. So I'm gonna create
我们不再需要它
1261
01:03:16,660 --> 01:03:19,294
another local variable which is also gonna be a constant,
我需要再新建一个局部变量，当然也是个常量
1262
01:03:19,296 --> 01:03:24,366
so it's let. I'm gonna call it textCurrentlyInDisplay, okay?
所以是let 。我叫它 textCurrentlyInDisplay
1263
01:03:24,368 --> 01:03:28,904
So I wanna get the text that's in this display currently. So
我想获得现在 display 里的字符
1264
01:03:28,906 --> 01:03:33,241
I'm going to send a message to display here, right? Display.
我要在这给 display 发一个消息
1265
01:03:33,243 --> 01:03:35,377
And the message, we can look it up in the documentation.
这个信息，我们可以从文档中得知
1266
01:03:35,379 --> 01:03:37,913
But the message that I want to send is text. Okay?
但是我想发的消息是文字
1267
01:03:37,915 --> 01:03:41,416
That gives me the text in the display. This is a UI label
这会给我 display 里的文字。这是个 UILabel 方法
1268
01:03:41,418 --> 01:03:45,453
method. But this is giving me an error. Okay, and
但这里却告诉我是个错误
1269
01:03:45,455 --> 01:03:48,690
the error that it's giving me here is that I haven't
这个错误说我这里没有 unwarp display
1270
01:03:48,692 --> 01:03:51,927
unwrapped display. You see that display is an optional
你看 display 是个 optional label
1271
01:03:51,929 --> 01:03:55,730
label. You can't send text to the type optional Okay, and
你不能把一个 text 赋给一个 optional
1272
01:03:55,732 --> 01:03:58,633
optional doesn't understand the message text.
optional 不理解什么是文字
1273
01:03:58,635 --> 01:04:02,003
UILabel does. So, we need to get that associated value
但 UILabel 知道。所以我们要获得 display 的 label 的关联值
1274
01:04:02,005 --> 01:04:05,207
of label, of a display, which is the UILabel, and
是一个 UILabel
1275
01:04:05,209 --> 01:04:07,843
we do that with the exclamation point, here.
我们会在这放一个感叹号
1276
01:04:07,845 --> 01:04:10,645
And, again, notice it's offering, here, to fix it. So,
注意这里，提供了修复选项
1277
01:04:10,647 --> 01:04:13,515
I'm gonna fix it, and i put the exclamation point in
所以我来修复他，就会放一个感叹号在这
1278
01:04:13,517 --> 01:04:17,752
there. Now, this is a UILabel. It's an unwrapped,
现在这里是个 UILabel，这一个 unwarpped
1279
01:04:17,754 --> 01:04:20,589
optional UILabel, right? This is a UILabel,
optional UILabel，对吗？这是一个 UILabel
1280
01:04:20,591 --> 01:04:22,624
and I'm sending it the message text,
我把那个文字值发给他
1281
01:04:22,626 --> 01:04:24,626
actually text is a property, just like currentTitle
实际上 text 是个属性， 就像 currentTitle
1282
01:04:24,628 --> 01:04:29,030
is a property on button, text is a property on UILabel. And,
是一个 button 的属性，text 是 UILabel 的一个属性
1283
01:04:29,032 --> 01:04:33,001
in fact, if I option+click on it, you'll see var text is an
如果我按住 option 点它，你可以看见 var text
1284
01:04:33,003 --> 01:04:37,806
optional string. Why? Because UILabel might be not set.
是一个 optional string。为什么？因为 UILabel 可能没有被赋值
1285
01:04:37,808 --> 01:04:40,275
The text in it might not be set. So it also is an option,
它里面的 text 可能没有被赋值，所以这也是个 optional
1286
01:04:40,277 --> 01:04:45,647
just like currentTitle. So I need to unwrap that as well.
就像 currentTitle 一样，我需要同样需要 unwarp
1287
01:04:46,316 --> 01:04:48,950
Okay? And so now I have a string,
所以我现在有个 string
1288
01:04:48,952 --> 01:04:51,052
which is the string that's in there. Now you're probably
就是这里这个
1289
01:04:51,054 --> 01:04:52,654
getting tired of these exclamation points and so
现在你可能对这个感叹号感到有点疲惫，我也是
1290
01:04:52,656 --> 01:04:54,422
am I, and we're gonna be able to get rid of them.
我们将要去掉它
1291
01:04:54,424 --> 01:04:56,358
Some in a second here, so not to worry.
一会就去掉，不用担心
1292
01:04:56,360 --> 01:04:58,693
Anyway, I have this text currently in display.
不管怎样，我现在在 display 里拿到了这个文字
1293
01:04:58,695 --> 01:05:02,697
So now I'm just gonna say that the displays, okay, and
所以现在，display
1294
01:05:02,699 --> 01:05:07,002
I'm unwrapping it, text = textCurrentlyInDisplay. I'm
unwarp 它，"text ＝ textCurrentlyInDisplay"
1295
01:05:07,004 --> 01:05:11,706
just hitting tab here, okay, + the digit that was pressed.
我在这按了 tab 键，然后代码写 "＋ digit"
1296
01:05:11,708 --> 01:05:14,809
Okay, notice that you can use + to concatenate strings.
注意你用加号来串联字符
1297
01:05:14,811 --> 01:05:17,913
That's really fun. Okay, some language allow that, some not.
这很有趣，有的语言允许这么做，有的不允许
1298
01:05:17,915 --> 01:05:21,816
So it does. Notice also that when I'm setting the value of
Swift 可以。同时注意我在给 optional 赋值的时候
1299
01:05:21,818 --> 01:05:25,120
an optional, remember text here is an optional string.
记住这里的 text 是个 optional string
1300
01:05:25,122 --> 01:05:28,123
I can set it to be a string, and that means,
我可以把它赋值为 string，这意味着
1301
01:05:28,125 --> 01:05:32,294
by definition, set this optional to set and
根据定义，是赋值给 optional 来设定
1302
01:05:32,296 --> 01:05:37,332
use this as its associated value. Right? Now,
把它赋为这个的关联变量
1303
01:05:37,334 --> 01:05:41,736
how do you think I would set this optional to not be set?
那么你认为我怎么才能给这个 optional 赋一个不赋值的状态？
1304
01:05:41,738 --> 01:05:45,206
Anyone know? You would say,
有人知道吗？
1305
01:05:45,208 --> 01:05:49,878
set this thing to be nil. This keyword means opp,
把它赋值为 nil，这个关键字
1306
01:05:49,880 --> 01:05:52,781
optional not set. So that would set this text.
表示 optional 没有被赋值。所以会赋这个值
1307
01:05:52,783 --> 01:05:56,051
It would blank out this text. It would set it to be not set.
这个栏里为空，这会把它赋为没有被赋值
1308
01:05:56,053 --> 01:05:58,119
Okay, so an optional you can, when you're setting it,
所以一个 optional，在你给它赋值的时候
1309
01:05:58,121 --> 01:06:02,190
you can set it to either nil or to an associated value.
你可以把它赋为 nil 或者是 关联值
1310
01:06:03,060 --> 01:06:06,261
Okay? Sound good? So let's run.
听起来不错？让我继续
1311
01:06:11,435 --> 01:06:13,401
All right, so hopefully when we press these buttons,
所以，理想情况下当我们按下按钮
1312
01:06:13,403 --> 01:06:15,971
it's going to append it on to the end, here. So let's try
数字就会被加到末尾
1313
01:06:15,973 --> 01:06:20,976
five, it did it. Eight, nine, although I'm not really a fan
5，它做到了。8，9，但是我不喜欢
1314
01:06:20,978 --> 01:06:25,313
of a zero at the beginning there. Okay, that zero is not
前面有个 0.所以
1315
01:06:25,315 --> 01:06:27,849
really how a calculator would work. Okay, when I press that
这不是一个计算器应该有的样子。当我按五的时候
1316
01:06:27,851 --> 01:06:30,452
five, I'm essentially typing a new number. It would get rid
实际上我是按了一个新数字。
1317
01:06:30,454 --> 01:06:33,021
of the zero. So, we really need a way to keep track of
它应该取代 0。所以需要一个方法
1318
01:06:33,023 --> 01:06:35,757
whether we're in the middle of typing a number or not. Cuz if
来追踪我们是不是在输入中
1319
01:06:35,759 --> 01:06:37,425
we're in the middle of typing a number,
因为如果我们在输入中
1320
01:06:37,427 --> 01:06:37,926
we do the apend thing, but
那就得把数字加到尾部
1321
01:06:37,928 --> 01:06:39,260
if we're not in the middle of typing a number,
如果不是
1322
01:06:39,262 --> 01:06:42,163
then we just replace whatever is in that display, right? So,
那就把之前的数字替换掉，对吗？
1323
01:06:42,165 --> 01:06:46,368
I'm going to add a new var, okay, a new instance variable,
我要加一个变量，实例变量
1324
01:06:46,370 --> 01:06:47,769
a new property, called,
一个新的属性
1325
01:06:47,771 --> 01:06:51,706
userIsInTheMiddleOfTyping. >> [LAUGH]
叫做 userIsInTheMiddleOfTyping（笑
1326
01:06:51,708 --> 01:06:52,474
>> Okay, now you laugh,
我知道你们为什么笑
1327
01:06:52,476 --> 01:06:54,609
you laugh because that seems like a lot of typing, but
你们笑是因为这个变量名字太长了
1328
01:06:54,611 --> 01:06:57,479
I will never have to type that again. Okay?
但我不会再做第二遍
1329
01:06:57,481 --> 01:06:59,948
Because Xcode is always gonna escape complete things for
因为 Xcode 总会帮我自动补全
1330
01:06:59,950 --> 01:07:02,751
me. So, long names like that are actually good.
所以长变量名挺好的
1331
01:07:02,753 --> 01:07:05,286
Okay, you wanna pick the shortest name that, you know,
你可以选一个短一点的名字
1332
01:07:05,288 --> 01:07:08,123
it conveys what you want but you want your names,
这名字要能体现出你想要什么
1333
01:07:08,125 --> 01:07:10,258
as you know in computer science naming is everything,
计算机科学里命名就是一切，你懂的
1334
01:07:10,260 --> 01:07:14,429
you want your names to be very, very, very good for
你希望你的命名对读你代码的人
1335
01:07:14,431 --> 01:07:17,432
the reader to understand what's going on, okay? Now,
非常非常非常的好理解
1336
01:07:17,434 --> 01:07:20,702
this userIsInTheMiddleOfTyping is a Bool, okay?
userIsInTheMiddleOfTyping 是个 Bool
1337
01:07:20,704 --> 01:07:21,603
So, I'm giving you it's type,
我给它一个 Bool 类型
1338
01:07:21,605 --> 01:07:23,905
Bool. It's not an optional Bool. It's just a Bool. So
这不是个 optional Bool，就是个 Bool
1339
01:07:23,907 --> 01:07:27,442
no question mark here. Okay, it's either true or false.
所以这里没有问候，这里无论 true 还是 false
1340
01:07:27,444 --> 01:07:28,777
I'm either in the middle of typing or I'm not.
我不是在输入中或没输入
1341
01:07:28,779 --> 01:07:32,313
Now as soon as I put that in there I got an error.
一旦我把这些放在这，就报错了
1342
01:07:32,315 --> 01:07:34,282
See that error up there? What? That's not fair.
看到上面那个报错符合了吗？这不科学啊
1343
01:07:34,284 --> 01:07:38,753
I didn't do anything up there. What is that? Let's click it.
我在上面什么都没做啊，那是什么？点一下看看
1344
01:07:38,755 --> 01:07:41,456
Class ViewController has no initializers.
Class ViewController has no initializers
1345
01:07:41,458 --> 01:07:43,725
Okay, now you're doing your homework and you're like,
这里如果你们正在做作业
1346
01:07:43,727 --> 01:07:46,161
what the, there's nothing to do, what I just did.
你会发现，我们什么都没做
1347
01:07:46,163 --> 01:07:48,496
I just typed in var here, what does that mean? Okay,
我只是刚才声明了一个变量，这是什么意思？
1348
01:07:48,498 --> 01:07:51,366
well the reason you're getting that error is cuz in Swift,
你在这报错的原因是
1349
01:07:51,368 --> 01:07:55,336
all properties, every single one, have to have an initial
在 Swift 里，所以的属性，每一个，都必须有一个初始化的值
1350
01:07:55,338 --> 01:07:59,340
value. There's no, you are not allowed to have
如果你不这么做
1351
01:07:59,342 --> 01:08:02,710
any properties that don't have an initial value. Okay?
就不能有一个未初始化的变量
1352
01:08:02,712 --> 01:08:04,612
So how do we give this thing an initial value?
所以我们怎么给它一个初始值？
1353
01:08:04,614 --> 01:08:07,715
Well, there's two ways. One, we create an initializer.
有两种方式，一种，对它进行初始化
1354
01:08:07,717 --> 01:08:08,683
That's why you're getting this warning.
这就是为什么会报错
1355
01:08:08,685 --> 01:08:11,486
Now I'm not gonna talk about initializers til next week. So
但下周前我不会讲怎么初始化
1356
01:08:11,488 --> 01:08:13,822
we can't do that because I'm not gonna talk about it yet,
所以我们不能做，因为我还没讲
1357
01:08:13,824 --> 01:08:16,324
okay? What's the other way that we can do it?
所以另一种是什么方式呢？
1358
01:08:16,326 --> 01:08:21,729
We can just say = false. Okay, so we just initialize that,
我们直接给它赋一个 false 值，我们这就对它初始化了
1359
01:08:21,731 --> 01:08:24,933
and the write error goes away. Woo hoo, were winning, and
那个报错就消失了～
1360
01:08:24,935 --> 01:08:26,067
I know some of you are saying, yeah,
我知道你们可能会说
1361
01:08:26,069 --> 01:08:30,839
what about this one? Okay, you didn't initialize that. Okay,
那么这个呢？你没对它初始化啊
1362
01:08:30,841 --> 01:08:33,741
that's because optionals are treated specially.
因为 optional 是很特殊的
1363
01:08:33,743 --> 01:08:39,047
They are always automatically initialized to not set.
他们会自动被初始化为空
1364
01:08:39,049 --> 01:08:42,550
Okay? So this is basically always happening
这就是你申明一个 optional 的时候会发生的
1365
01:08:42,552 --> 01:08:44,686
when you have an optional, or var that's an optional.
或者是一个 var 的 optional
1366
01:08:44,688 --> 01:08:46,287
Which makes sense, right? You have an optional.
能理解吗？你有一个 optional
1367
01:08:46,289 --> 01:08:47,589
It's not set until you set it to something.
它没有被赋值，直到你给它赋一个值
1368
01:08:47,591 --> 01:08:51,960
So it starts out not set. Okay, so that's why it is set.
所以它会以没有赋值开始。这就是为什么它被赋值了
1369
01:08:51,962 --> 01:08:55,630
It's set to not set. Okay? All right, so
它被赋值为没有赋值
1370
01:08:55,632 --> 01:08:57,665
we have this thing now, we have this. Let's go ahead and
所以我们现在有了这个，继续
1371
01:08:57,667 --> 01:09:00,635
use this thing we created. Actually, I'm going to do one
所有现在用我们刚刚创建的这个
1372
01:09:00,637 --> 01:09:05,940
more thing here. You see this : Bool? Do we need that? No.
我还要在这多做一件事。: Bool 我们真的需要这个吗？不
1373
01:09:05,942 --> 01:09:09,611
Okay, why don't we need that? Because false can only be
为什么我们不需要这个呢？
1374
01:09:09,613 --> 01:09:15,750
a Bool, so Swift can infer that the type of this is Bool.
因为false 只能是个Bool 型。所以Swift 可以推导它就是个Bool 型
1375
01:09:15,886 --> 01:09:19,821
See that? Okay? All right. So, we have this
看到了吗？所以我们现在有了 userIsInTheMiddleOfTyping
1376
01:09:19,823 --> 01:09:23,057
userIsInTheMiddleOfTyping. We only wanna do this business
我们只想它处理
1377
01:09:23,059 --> 01:09:25,493
right here if the user is in the middle of typing.
用户是不是正在输入中的问题
1378
01:09:25,495 --> 01:09:26,995
So now we're gonna see in if statement.
所以我接下来输入
1379
01:09:26,997 --> 01:09:28,263
If the user is in the middle of typing,
If userIsInTheMiddleOfTyping
1380
01:09:28,265 --> 01:09:31,232
now again, I'm just hitting Tab here. Look Mom, no hands,
我按下 Tab 键，这一串就输入好了。
1381
01:09:31,234 --> 01:09:34,302
or one hand. If the user is in the middle of typing,
If userIsInTheMiddleOfTyping
1382
01:09:34,304 --> 01:09:36,938
then we're gonna do this thing. Okay.
然后我们做这些
1383
01:09:36,940 --> 01:09:40,742
If the user's not in the middle of typing,
如果用户不是在输入中
1384
01:09:40,744 --> 01:09:43,378
then we're gonna set the displays text
那么就让 display 的文本
1385
01:09:43,380 --> 01:09:46,481
equal to the digit we just typed. Okay, the five, or
等于 digit 的数字。比如 5，或者别的什么
1386
01:09:46,483 --> 01:09:49,417
whatever, we're gonna replace what's in the display. And,
我们会替换 display 里的文本
1387
01:09:49,419 --> 01:09:52,921
of course, in either case, the user is definitely, no long,
当然，另一种情况，用户
1388
01:09:52,923 --> 01:09:56,024
is definitely, now, in the middle of typing. Okay,
一定是在输入中
1389
01:09:56,026 --> 01:09:59,561
cuz you just touched a digit, we're clearly in the middle of
因为你刚刚按了输入按钮，我们显然是在输入中
1390
01:09:59,563 --> 01:10:03,097
typing. Now I'm getting pretty tired of typing display
我现在真的对每次都
1391
01:10:03,099 --> 01:10:05,466
exclamation point all the time, okay?
输入display! 感到疲惫
1392
01:10:05,468 --> 01:10:08,303
All the time typing display exclamation point, when in
每次都输入 display! ，实际上
1393
01:10:08,305 --> 01:10:12,307
fact, I know that that display is pretty much always set.
我知道 display 一定是被赋值的状态
1394
01:10:12,309 --> 01:10:14,776
Okay, the only time that this is not set is for
它唯一没被赋值的时间就是
1395
01:10:14,778 --> 01:10:18,546
a nanosecond when this starts to come on screen,
当他一出现在屏幕上的时候
1396
01:10:18,548 --> 01:10:22,650
before iOS has a chance to wire it up to this UILabel.
在 iOS 把他变成 UILabel 类型之前
1397
01:10:22,652 --> 01:10:25,119
But once it's wired up, it's set forever. And
一旦他被连接上，那就永远被赋值了
1398
01:10:25,121 --> 01:10:27,589
certainly by the time users are touching on digits,
而且很确定的是，当用户点在数字上时
1399
01:10:27,591 --> 01:10:31,226
the UIs completely on screen, and wired up, and so I know
UI 已经在屏幕上创建好、链接好了，
1400
01:10:31,228 --> 01:10:36,097
that's never going to be nil. Never, okay, in this code. So
所以我知道它用不会为空
1401
01:10:36,099 --> 01:10:38,199
why am I forced to type display, exclamation point,
所以我为什么非要
1402
01:10:38,201 --> 01:10:39,801
display, exclamation point, over and over, okay?
重复输入 display! 呢？
1403
01:10:39,803 --> 01:10:42,670
And the answer is you don't have to because we're
答案是你不需要，
1404
01:10:42,672 --> 01:10:46,007
gonna go back and change this question mark to be
我们只要把一开始这个问号
1405
01:10:46,009 --> 01:10:48,910
exclamation point. Basically if you put the exclamation
改成感叹号。总的来说，
1406
01:10:48,912 --> 01:10:53,481
point where you declare it, it says that anyone can use
在你定义的时候放个感叹号，就表示所有对象都可以用这个
1407
01:10:53,483 --> 01:10:57,252
this thing, and it will implicitly unwrap it, okay?
就 implicitly unwarp（注：隐式解包）了这个对象
1408
01:10:57,254 --> 01:10:57,986
It will automatically unwrap it.
这就会自动 unwarp
1409
01:10:57,988 --> 01:10:59,988
Now its still unwrapping it, so if that was nil,
现在它还是会 unwarp，如果他是 nil
1410
01:10:59,990 --> 01:11:04,292
it will still crash, okay? But it allows me to get rid of all
它还是会让你的应用崩溃。但是它允许我
1411
01:11:04,294 --> 01:11:08,529
of these exclamation points. Okay? Because it's implicit
去掉这里所有的感叹号
1412
01:11:08,531 --> 01:11:10,365
that there's an exclamation point on all of them,
因为这里的感叹号 implicit unwarp（隐式解包）了所有的对象
1413
01:11:10,367 --> 01:11:12,200
because instead of putting a question mark here,
因为我在这放了个感叹号
1414
01:11:12,202 --> 01:11:13,468
I put the exclamation point up there.
而不是问号
1415
01:11:13,470 --> 01:11:15,837
Everyone got that? >> [INAUDIBLE].
都懂了吗
1416
01:11:15,839 --> 01:11:16,471
>> It would crash down here,
可能会在下面这里崩溃
1417
01:11:16,473 --> 01:11:18,906
in this code down here. As soon as you access this,
这一块代码，一旦你跑到这
1418
01:11:18,908 --> 01:11:21,709
if that were nil, boom, it would be unwrapping it,
如果是个 nil，就会 unwarp
1419
01:11:21,711 --> 01:11:24,445
cuz it's implicitly unwrapped >> And again,
因为它 implicitly unwarp 了
1420
01:11:24,447 --> 01:11:25,980
if I change this back to a question mark,
如果我把它改回问号
1421
01:11:25,982 --> 01:11:28,416
now I'm gonna get all kinds of warnings down here.
现在就会出现好多警告、错误
1422
01:11:28,418 --> 01:11:30,485
See errors, because I'm not unwrapping it, but
因为我没有 unwarp 它
1423
01:11:30,487 --> 01:11:31,719
if I put the exclamation point,
如果我在这放一个感叹号
1424
01:11:31,721 --> 01:11:33,821
now I'm in implicitly unwrapping it everywhere.
这样我就在所有地方 implicitly unwarp 了
1425
01:11:33,823 --> 01:11:36,658
Okay, that's called an implicitly unwrap optional.
这样就可以叫它 implicitly unwarp 的 optional
1426
01:11:36,660 --> 01:11:39,694
Very important,
非常重要
1427
01:11:39,696 --> 01:11:43,765
Okay, so now let's go see if that fixed everything?
我们现在看看它是不是修复了所有问题
1428
01:11:47,404 --> 01:11:47,602
>> All right, so
所以
1429
01:11:47,604 --> 01:11:48,536
now hopefully when we press five,
当我们按下5
1430
01:11:48,538 --> 01:11:50,772
it will get rid of the zero. Five. There it is, and
就会去掉 0 显示 5
1431
01:11:50,774 --> 01:11:53,808
this is still working. Okay? So that's good. We're
我们做的很好
1432
01:11:53,810 --> 01:11:56,778
doing great. Our keyboard is basically fully functional at
这下我们的键盘功能完全了
1433
01:11:56,780 --> 01:11:59,147
this point. So now we want to add a,
现在要加一个操作
1434
01:11:59,149 --> 01:12:02,216
an operation. Now, because of our technical thing,
因为技术上的原因
1435
01:12:02,218 --> 01:12:04,319
we're running out of time, but I have 3 minutes left.
我们快没时间了，但还有三分钟
1436
01:12:04,321 --> 01:12:07,021
I'm gonna add the pi button. Okay, pi is a very
我要加一个 π 按钮
1437
01:12:07,023 --> 01:12:10,024
simple operation. It's just gonna put pi in the display.
π 是个很简单的操作。只是放个 π 在 display 上
1438
01:12:10,026 --> 01:12:13,461
So let's do that. I'm gonna do that by taking the 7 button
来做这个吧。我要选中 7 这个按钮
1439
01:12:13,463 --> 01:12:14,362
and copying and pasting it.
复制粘贴它
1440
01:12:14,364 --> 01:12:17,665
That's a really bad idea, as you'll see in a moment. But,
现在看来这很不好
1441
01:12:17,667 --> 01:12:20,768
I'm just going to do that and call it pi, okay? Now,
但我就这么做了，叫它 π
1442
01:12:20,770 --> 01:12:24,706
of course, pi is not a digit button, it's an operation, so
当然，π 不是个数字，是一个操作
1443
01:12:24,708 --> 01:12:30,044
I'm going to Ctrl drag down here to create another action,
我要按住 ctrl 键拖到这里，创建另外一个 action
1444
01:12:30,046 --> 01:12:30,878
a different action.
一个不同的 action
1445
01:12:30,880 --> 01:12:34,082
This action is performOperation because pi
这是个 performOperation 因为 π 是个操作
1446
01:12:34,084 --> 01:12:36,517
is an operation. I'm gonna have all my operation buttons
我会把所有操作的按钮叫做 performOperation
1447
01:12:36,519 --> 01:12:39,721
called performOperation. And of course I'm not gonna forget
当然我不会忘了
1448
01:12:39,723 --> 01:12:41,289
to change that to UI button, okay,
把它换成 UIButton
1449
01:12:41,291 --> 01:12:43,491
either are you on your homework, right? Okay?
你们做作业的时候也别忘了
1450
01:12:43,493 --> 01:12:47,095
And here it is, so there's perform operation right there,
所以 performOperation 就在这了
1451
01:12:47,097 --> 01:12:50,064
okay. And perform operation, I'm gonna do the exact same
对 performOperation 我要做跟
1452
01:12:50,066 --> 01:12:52,734
thing that I did at the beginning of touch digit,
之前按 digit 一样的事情
1453
01:12:52,736 --> 01:12:55,002
which is I'm gonna ask the sender which
要问 sender
1454
01:12:55,004 --> 01:13:00,208
operation are you? So I'm gonna let mathematicalSymbol =
你是哪个操作
1455
01:13:00,210 --> 01:13:05,580
the sender.currentTitle. Now of course
let mathematicalSymbol = sender.currentTitle
1456
01:13:05,582 --> 01:13:09,083
I want the string so I could do the exclamation point,
我需要 string，我可以用感叹号
1457
01:13:09,085 --> 01:13:13,321
okay? But if this were blank, what if I just wanted to
如果这是空的，如果我只想忽略
1458
01:13:13,323 --> 01:13:17,658
ignore that operation press? Okay, instead of crashing.
这个按下的动作呢？而不是让它崩溃
1459
01:13:17,660 --> 01:13:20,027
Okay, what if it was legal to have that
如果让它为空是合法的
1460
01:13:20,029 --> 01:13:24,165
be blank. Okay? I basically want to unwrap
我只想它被赋值的时候 unwarp
1461
01:13:24,167 --> 01:13:29,036
only if this is set. So the way you do that is
你做这个的方式
1462
01:13:29,038 --> 01:13:32,240
you don't put the exclamation point there. Instead,
就是不要在这放个感叹号
1463
01:13:32,242 --> 01:13:37,412
you put if at the beginning. And what's nice about this is
如果你在前面放个 if
1464
01:13:37,414 --> 01:13:42,116
very little typing but also look how it reads, okay? If I
这很好，也看看这是怎么写的。
1465
01:13:42,118 --> 01:13:47,422
can let mathematicalSymbol = sender .currentTitle, then I'm
if let mathematicalSymbol = sender.currentTitle
1466
01:13:47,424 --> 01:13:50,458
gonna do something. Okay, so it reads just like English,
然后再做一些什么。读起来像是英文
1467
01:13:50,460 --> 01:13:54,462
it's a really nice way to unwrap. So inside this if,
这是 unwarp 的很好的方式
1468
01:13:54,464 --> 01:13:57,064
this will be a string. It'll be the associated
在这个 if 里，这会是个 string
1469
01:13:57,066 --> 01:14:00,701
value of currenttype, Title. Outside of this if,
这会是 currentTitle 的关联值
1470
01:14:00,703 --> 01:14:01,302
it's not even defined.
if 之外，它甚至没有被定义
1471
01:14:01,304 --> 01:14:04,071
mathematicalSymbol won't even be defined. Okay? Super
mathematicalSymbol 甚至没被定义
1472
01:14:04,073 --> 01:14:10,011
simple. So here I can just say if mathematicalSymbol = pi,
超简单，所以我们只要 let mathematicalSymbol == π
1473
01:14:10,013 --> 01:14:14,782
by the way Alt + P to make pi, okay, then I can set my
按alt ＋ P 就是π ，然后设置display
1474
01:14:14,784 --> 01:14:18,619
displays. I don't even need the exclamation point anymore.
我甚至不再需要感叹号
1475
01:14:18,621 --> 01:14:22,924
Text = pi, which _pi is pi if we
Text = M_PI
1476
01:14:22,926 --> 01:14:27,762
Alt click on this. This is a symbol. See? M under bar PI.
按 alt 点它。这是个符号。M_PI
1477
01:14:27,764 --> 01:14:30,865
It's a double. It's a double vision value of PI. Now,
是个 double。这是个 double 类型的 π 值
1478
01:14:30,867 --> 01:14:33,301
we have an error here. Why do we have an error?
这里报错了，为什么呢？
1479
01:14:33,303 --> 01:14:36,504
Because it says it cannot assign a type double to
因为不能把一个 double 赋值给
1480
01:14:36,506 --> 01:14:39,073
something that is a string question mark, right?
一个 string？
1481
01:14:39,075 --> 01:14:42,577
We know the display.text right here is a string question mark
我们知道这是个 display.text 是个 string？
1482
01:14:42,579 --> 01:14:45,780
so we can't do that. So, how do we convert this double to
我们不能这么做，所以我们怎么把这个 double
1483
01:14:45,782 --> 01:14:49,317
a string? And the answer is we have to create a new string.
转换成一个 string？答案是新建一个 string
1484
01:14:49,319 --> 01:14:51,886
Okay, and now you're gonna see how to create new
这样你会看到我们如何
1485
01:14:51,888 --> 01:14:56,290
instances of objects in Swift, and the answer is you just put
在 Swift 里新建一个实例。答案是
1486
01:14:56,292 --> 01:14:59,694
the name of the class and then parentheses and then inside
打出这个类型名，然后把
1487
01:14:59,696 --> 01:15:02,263
the parentheses you can put anything that the class
任何允许你转换的值
1488
01:15:02,265 --> 01:15:06,501
will allow you to create one of itself with. Okay, and
放在括号里
1489
01:15:06,503 --> 01:15:07,702
you can have multiple of these.
你可以多次创建
1490
01:15:07,704 --> 01:15:10,538
These are the initializers referred to earlier. And
这是个早前的初始化方式
1491
01:15:10,540 --> 01:15:14,141
string happens to be able to take a double as one of
string 可以把一个 double
1492
01:15:14,143 --> 01:15:16,444
the things that it knows how to create a new string. So
创建成一个新的 string
1493
01:15:16,446 --> 01:15:19,947
this creates a new string, okay, from a double. So
所以它从一个 double 创建一个新的 string
1494
01:15:19,949 --> 01:15:22,683
the string class knows how to look at a double, turn it into
string 类知道如何把一个 double
1495
01:15:22,685 --> 01:15:27,455
a bunch of characters that are a double, okay? So
转换成一个字符串
1496
01:15:27,457 --> 01:15:34,161
we'll run this. Okay,
所以再跑一下
1497
01:15:34,163 --> 01:15:37,732
so here we go, this is still working and if we press Pi,
这还是好用的，当我们按下 π
1498
01:15:37,734 --> 01:15:40,568
we get Pi [SOUND], we got a problem, okay?
我们得到 π 值，但有个问题
1499
01:15:40,570 --> 01:15:41,836
It's not fitting the whole Pi,
没有显示全 π
1500
01:15:41,838 --> 01:15:43,971
all the digits. We can fix that really easily.
我们可以很简单的修复一下
1501
01:15:43,973 --> 01:15:47,475
I'm gonna go back to here. And if we look at the inspector,
我们回到这里，看一下 inspector
1502
01:15:47,477 --> 01:15:51,245
there's a nice feature in label called autoshrink.
有个非常好的 UILabel 特性叫 autoshrink
1503
01:15:51,247 --> 01:15:53,881
And I'm gonna make it so it autoshrinks but
我会让这个 autoshrink
1504
01:15:53,883 --> 01:15:59,320
no smaller than 9 point, okay. That's gonna fix that one.
不小于 9 点。这就会修复
1505
01:15:59,322 --> 01:16:02,757
We have one more problem. Okay, so we have,
我们还有个问题
1506
01:16:02,759 --> 01:16:05,960
this is working, pi, what's that?
这个 π 又是啥
1507
01:16:05,962 --> 01:16:09,196
We got a little pi on the end there and also look at this,
我们在最后有一个 π，还有，看这个
1508
01:16:09,198 --> 01:16:12,600
that, what a mess. So we got two problems there. For
这很不好。我们现在这里有两个问题了
1509
01:16:12,602 --> 01:16:15,436
some reason when we press pi, it puts pi on the end.
因为一些原因，当我们按 π，最后有个 π 在末尾
1510
01:16:15,438 --> 01:16:19,173
Well,why is that? Okay. That's because, let's look at
为什么呢？因为看这个
1511
01:16:19,175 --> 01:16:22,276
this little thing. Okay. Pi is sending that, right?
π 会发送这个
1512
01:16:22,278 --> 01:16:26,480
How about this one? Pi is sending that too.
这个呢？π 也会发送这个
1513
01:16:26,482 --> 01:16:31,252
You see, it's sending touch digit and perform operation.
它同时响应两个方法
1514
01:16:31,254 --> 01:16:33,754
That's because I copied and pasted the 7
因为我复制黏贴了7
1515
01:16:33,756 --> 01:16:37,358
which sent touch digit and then I added this one. Okay,
所以也发送上面的这个方法
1516
01:16:37,360 --> 01:16:40,061
now how do we fix that? You fix that by right-clicking on
那我怎么修复呢？
1517
01:16:40,063 --> 01:16:42,663
the button. If you right-click on anything in your UI, you'll
可以右击这个按钮
1518
01:16:42,665 --> 01:16:45,266
see all of the connections that it has. Very important to
可以看到所有按钮关联的东西
1519
01:16:45,268 --> 01:16:47,668
understand right-click, okay. So you right-click and
理解右击很重要
1520
01:16:47,670 --> 01:16:49,203
you can see it only has two connections here.
右击，你可以在这看到两个链接
1521
01:16:49,205 --> 01:16:52,239
It's connected to touch digit and to perform operation, so
这链接了两个方法
1522
01:16:52,241 --> 01:16:55,509
I'm just gonna get rid of the touch digit by clicking this,
我只是需要去掉 touchDigit
1523
01:16:55,511 --> 01:16:57,178
gone. Now it only does perform digit,
这样就只想响应下面这个方法了
1524
01:16:57,180 --> 01:17:00,715
or perform operation, okay. So we fixed that problem where
所以我们修复了
1525
01:17:00,717 --> 01:17:02,149
we're just putting pi on the end, all right.
这个末尾有π 的问题
1526
01:17:02,151 --> 01:17:05,453
And the other problem was that when we have the pi and
另一个问题是，当我们有π 的时候
1527
01:17:05,455 --> 01:17:05,987
I started typing numbers,
再按数字
1528
01:17:05,989 --> 01:17:07,922
it thought I was in the middle of typing a number and
会认为你在输入中
1529
01:17:07,924 --> 01:17:11,025
it was adding them on. So that's simple, I'm just gonna
会在末尾加数字，这很简单
1530
01:17:11,027 --> 01:17:14,228
say userIsInTheMiddleofTyping number = false.
userIsInTheMiddleofTyping = false
1531
01:17:14,230 --> 01:17:16,364
Okay, whenever we perform an operation,
无论我什么时候操作
1532
01:17:16,366 --> 01:17:19,767
it's gonna wipe out what's in my display so I'm obviously
就会去掉之前 display 上的东西
1533
01:17:19,769 --> 01:17:22,703
not in the middle of typing a number anymore and we have
因为我很显然不是在输入中
1534
01:17:22,705 --> 01:17:28,242
a fully functional calculator with one operation. 45 pi 89,
现在我有了个全功能的计算器按钮
1535
01:17:28,244 --> 01:17:32,780
okay? So on Wednesday, we'll pick up
周三，我们会继续
1536
01:17:32,782 --> 01:17:35,516
with some more, make a more powerful calculator. Sorry to
做个更强的计算器
1537
01:17:35,518 --> 01:17:38,486
run over a little bit because of technical difficulties,
抱歉，因为技术难题拖课了一会
1538
01:17:38,488 --> 01:17:40,054
see you then. >> For
下回见
1539
01:17:40,056 --> 01:17:40,087
more please visit us at stanford.edu.
更多内容详见：stanford.edu
================================================
FILE: subtitles/10. Core Data.srt
================================================
1
00:00:00,001 --> 00:00:03,469
[MUSIC]
2
00:00:03,471 --> 00:00:09,508
Stanford University. >> Welcome to Lecture Number
3
00:00:09,510 --> 00:00:13,746
10 of Stanford CS193P. It's the Spring of 2016.
4
00:00:13,748 --> 00:00:18,250
Today we have one topic only, which is Core Data, okay,
5
00:00:18,252 --> 00:00:22,221
which is an object oriented database. Sometimes when
6
00:00:22,223 --> 00:00:24,957
you're building an app you need to store a huge amount of
7
00:00:24,959 --> 00:00:27,926
data like you're doing some kind of twitter thing where
8
00:00:27,928 --> 00:00:29,294
you're collecting all the tweets and
9
00:00:29,296 --> 00:00:29,995
you've got all these tweets and
10
00:00:29,997 --> 00:00:31,030
you want to search through them and
11
00:00:31,032 --> 00:00:33,632
do some kind of queries or something like that. And
12
00:00:33,634 --> 00:00:36,735
of course there's lots of technologies out there for
13
00:00:36,737 --> 00:00:40,005
doing that kind of thing. SQL databases and
14
00:00:40,007 --> 00:00:42,274
things like that. But really when we're programming,
15
00:00:42,276 --> 00:00:45,778
we want obviously all of our stuff to be object oriented.
16
00:00:45,780 --> 00:00:49,648
So iOS has this awesome object oriented database system
17
00:00:49,650 --> 00:00:53,252
called Core Data. It's very powerful.
18
00:00:53,254 --> 00:00:55,020
It's actually based on SQL underneath so
19
00:00:55,022 --> 00:00:58,090
it's got all the full kind of power of that.
20
00:00:58,325 --> 00:01:01,393
And yet it interacts with your code just like all your other
21
00:01:01,395 --> 00:01:02,761
object oriented stuff that you do,
22
00:01:02,763 --> 00:01:04,997
especially if you're doing things like table and
23
00:01:04,999 --> 00:01:07,666
stuff like that that has a lot of good integration,
24
00:01:07,668 --> 00:01:10,269
with that. So it's essentially a way of
25
00:01:10,271 --> 00:01:14,039
creating an object graph that's backed by a database,
26
00:01:14,041 --> 00:01:14,840
a SQL database in this case.
27
00:01:14,842 --> 00:01:17,776
It can actually be backed by other kinds of databases
28
00:01:17,778 --> 00:01:19,678
like XML or just in memory stuff but
29
00:01:19,680 --> 00:01:23,015
primarily we're using Core Data with SQL as our,
30
00:01:23,017 --> 00:01:25,050
backing store. And the way it works,
31
00:01:25,052 --> 00:01:29,054
is you're going to create this visual mapping, okay? And
32
00:01:29,056 --> 00:01:32,024
then you're gonna create objects in your code. Visual
33
00:01:32,026 --> 00:01:33,892
mapping's gonna basically describe your database,
34
00:01:33,894 --> 00:01:36,061
then you're gonna create objects in your code,
35
00:01:36,063 --> 00:01:38,831
that are in that database. And you're gonna access
36
00:01:38,833 --> 00:01:41,800
the columns in the database, and the rows, and
37
00:01:41,802 --> 00:01:42,000
the columns and
38
00:01:42,002 --> 00:01:44,069
the tables if you want to think of it that way, but
39
00:01:44,071 --> 00:01:46,738
you can access the attributes just using vars.
40
00:01:46,740 --> 00:01:49,141
So you're gonna have objects and vars on them and
41
00:01:49,143 --> 00:01:52,211
those are gonna be stored in the database, okay.
42
00:01:52,213 --> 00:01:54,813
So I'm gonna walk you through all that. Let's start with
43
00:01:54,815 --> 00:01:57,916
creating that visual mapping of the database, okay.
44
00:01:57,918 --> 00:02:01,253
Now just like anything, that you do when you're
45
00:02:01,255 --> 00:02:04,189
adding a new file to x code, whether it's a swift file or
46
00:02:04,191 --> 00:02:07,593
something like that, you're going to start with new file.
47
00:02:07,595 --> 00:02:08,527
But in this case, we're not going
48
00:02:08,529 --> 00:02:11,196
to be adding a code file, we're actually going to be
49
00:02:11,198 --> 00:02:15,134
adding a database mapping file. So, you say new file,
50
00:02:15,136 --> 00:02:18,570
and you're going to go down to iOS Core Data, okay? You see
51
00:02:18,572 --> 00:02:23,075
where it says Core Data down there instead of, iOS source,
52
00:02:23,077 --> 00:02:25,611
and inside of there, you're gonna pick data model.
53
00:02:25,613 --> 00:02:30,115
Don't pick mapping model, you want data model, okay? And
54
00:02:30,117 --> 00:02:32,818
it's gonna ask you what you wanna call this mapping.
55
00:02:32,820 --> 00:02:33,986
Okay, this mapping, by the way,
56
00:02:33,988 --> 00:02:37,089
what we're mapping between is these objects that we're gonna
57
00:02:37,091 --> 00:02:40,692
describe in this database and what's gonna be in our code.
58
00:02:40,694 --> 00:02:44,796
And usually if you only have one database in your app
59
00:02:44,798 --> 00:02:47,599
you'll call it model, because it's usually the model for
60
00:02:47,601 --> 00:02:49,601
a lot of your view controllers, but you could
61
00:02:49,603 --> 00:02:52,571
also call it the name or your app or if you had multiple of
62
00:02:52,573 --> 00:02:55,307
them you could kind of name them appropriately, right, so
63
00:02:55,309 --> 00:02:59,845
any name will, is fine here. When you create it,
64
00:02:59,847 --> 00:03:03,415
looks like this, okay? It's called Model.xcdatamodeld
65
00:03:03,417 --> 00:03:07,319
right here. And this is the contents of it, right?
66
00:03:07,321 --> 00:03:10,022
We're looking at the contents of it. And,
67
00:03:10,024 --> 00:03:14,026
it's kind of like a storyboard for the database, okay?
68
00:03:14,028 --> 00:03:14,626
You're gonna graphically,
69
00:03:14,628 --> 00:03:19,198
visually edit your database schema right here. So
70
00:03:19,200 --> 00:03:21,934
the database lets you store things obviously.
71
00:03:21,936 --> 00:03:25,003
The main things that you're storing are called entities,
72
00:03:25,005 --> 00:03:28,407
okay? And they're kinda analogous to objects,
73
00:03:28,409 --> 00:03:31,076
all right? So here I'm gonna create an entity so
74
00:03:31,078 --> 00:03:33,645
I'm gonna click on this add entity button at the bottom.
75
00:03:33,647 --> 00:03:37,249
And just say add entity. When I do, it creates one up here.
76
00:03:37,251 --> 00:03:39,218
And I'm gonna change the name of it to Tweet.
77
00:03:39,220 --> 00:03:42,321
So for my examples today, let's say we're building
78
00:03:42,323 --> 00:03:44,523
a database that's storing some Twitter stuff.
79
00:03:44,525 --> 00:03:45,524
We're all in kinda Twitter mode
80
00:03:45,526 --> 00:03:48,660
right now with your assignment stuff. So we'll store some
81
00:03:48,662 --> 00:03:54,333
tweets and some Twitter users into this database, okay? Now
82
00:03:54,335 --> 00:03:57,769
this entity Tweet that we're gonna store in the database,
83
00:03:57,771 --> 00:04:01,673
they're gonna appear in our code as NSManagedObject
84
00:04:01,675 --> 00:04:05,978
instances. So there's a class in iOS NSManagedObject, okay.
85
00:04:05,980 --> 00:04:09,381
And so all these entities will appear in our code as
86
00:04:09,383 --> 00:04:14,953
NSManagedObject, okay. All right so in addition
87
00:04:14,955 --> 00:04:19,024
to entities these entities have attributes. So those
88
00:04:19,026 --> 00:04:21,727
are kind of like properties on a class right there.
89
00:04:21,729 --> 00:04:25,030
They have relationships. Relationships are kind of like
90
00:04:25,032 --> 00:04:29,668
vars that point to other objects in the database, okay.
91
00:04:29,670 --> 00:04:32,337
And then there also have this thing down here called fetch
92
00:04:32,339 --> 00:04:35,340
properties. Which I'm not gonna really talk about but
93
00:04:35,342 --> 00:04:36,708
kind of the name implies what they are.
94
00:04:36,710 --> 00:04:40,045
They're essentially properties that are, that basically
95
00:04:40,047 --> 00:04:43,382
represent fetching in the database. So pulling objects
96
00:04:43,384 --> 00:04:46,018
out that meet some query or something like that. You can
97
00:04:46,020 --> 00:04:48,353
make it look like that's just a property on you're entity.
98
00:04:48,355 --> 00:04:50,422
Unfortunately, don't have time to talk about that.
99
00:04:50,424 --> 00:04:53,525
We're gonna focus here on these attributes and
100
00:04:53,527 --> 00:04:55,560
relationships, okay?
101
00:04:55,562 --> 00:04:58,897
So to add an attribute, we're going to hit this little plus
102
00:04:58,899 --> 00:05:00,399
sign right here under the attributes and
103
00:05:00,401 --> 00:05:03,502
it's going to add one. Here, I'm doing a Tweet, right,
104
00:05:03,504 --> 00:05:06,371
that's my entity as a Tweet, so I'm going to put the text
105
00:05:06,373 --> 00:05:10,342
of the Tweet. Notice as soon as I type, as I added this and
106
00:05:10,344 --> 00:05:12,444
typed it in, I get start getting an error right here.
107
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See, red error up in the, upper corner there, okay.
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And that's because this Tweet or
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this text attribute on the Tweet has no type, okay.
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Everything that goes in there obviously has to have a type,
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so you just click on this type to set it and
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I'm gonna set the text to be a string. Okay, so these are all
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the types that the attributes, the vars in your Tweet entity
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can be basically. All the ones like integers, decimal,
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double, float, even Boolean, those are actually stored as
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an NS number. Those appear in your code as an NS number.
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Okay, this binary data is in NS data.
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The date is an NSDate, and the string here is an NSString.
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Now remember that you get the automatic bridging, right?
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From NSString to string, things like that,
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even from double and int to NSNumbers, right?
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So, even though these are NSNumbers and NSString,
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you're still gonna get your Swift-like things when you're
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using them, in your code. Now, you can set any of these
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things, like this text attribute using these two
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methods right here on NSManagedObject, okay?
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Value for key which gets the value, and set value for
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key. Okay, so valueForKey returns any object,
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could be an NSNumber or an NSDate or an NSData, right.
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And setValue(forKey:) the key is a string like text and
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the value is, again, NSNumber, NSData, NSDate, whatever,
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okay? So that's how you can set the data on your object
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once you get a hold of one of these NSManagedObject.
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Now I haven't shown you how to get those NSManagedObject yet,
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but I will soon.
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See the error's gone because I set this to be a string. So,
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here's I'm going to add some more attributes, an ID,
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which is some unique identifier for this Tweet.
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Also created, which is the date the Tweet was created,
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you can see that's an NSDate right there. By the way,
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this ID you're probably going to want that in your homework.
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Just a little hint.
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I like to give you hints sometimes in the lecture.
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So you'll need your unique ID there at some point.
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We're looking at these attributes on this entity in
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kind of a table format here. But we can also do it in
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a graphical way by clicking on this little button down here,
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this editor style. It changes the style of this editor and
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it looks like this. So the graphical one basically has
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all of my entities and my attributes, but in kind of
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on a graph paper graphical format. And this is going to
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make sense when I start having a lot of relationships between
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entities, right.
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Then I'm gonna be able to see them here on the graph paper
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all pointing to each other so
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I can see what their relationships are. Okay, so
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let's add another entity in this. We can add entities and
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attributes in this view just as much as in the table view.
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So I'm gonna go down here and add another entity.
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This is gonna be a Twitter user, okay? And you can see it
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added the Twitter user here. It has no attributes or
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relationships yet. What's really cool,
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if you move these around and they do have wires pointing
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to each other, it'll rearrange the wires all over the place
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to look nice, okay? So that's kinda fun. I can also add
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attributes from here. So I'm just going down here and
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say add attribute to add an attribute to my Twitter user.
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I'm gonna call this attribute screen name, okay,
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that's like the at sign, whatever, screen name
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of the user. Notice that if I have this selected,
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then the Inspector over here can be used to inspect things
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00:08:37,718 --> 00:08:41,753
about this attribute. So let's do that. Here's a screen name,
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its attributes. For example, here's its type.
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I'm going to say this type to be a string. It has some other
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attributes here which I'm not really going to have time to
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talk about. But you'll definitely, you can look up.
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You won't need it for any of your homework obviously, but
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for your final project you might. So
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you can look those up in the documentation for core data.
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Mkay I'm gonna add another attribute here which is name.
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So that's the user's real name.
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Okay not their at time whatever but their actual real
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name. So I'll add that. And now I'm gonna add
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a relationship between these two entities and of course we
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know that a Twitter user Is the one who tweets the tweet.
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Right? So, there's a relationship between this two.
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And to create a relationship between these two,
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I just Ctrl-drag from one to the other.
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And I can Ctrl-drag from either to the other.
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It really doesn't matter which direction.
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And when I do that, it's going to create
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a new thing over here called a relationship on both sides,
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it called it new relationship by default,
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we're going to change the name of that, okay, on both sides,
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and you can see it's got an arrow that points both ways.
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So now we know there's a relationship on both sides.
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Now, we want to rename these relationships
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just like the attributes have names that are meaningful,
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we want these to be meaningful names too. So the tweet okay,
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if you look at this relationship to this guy.
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This is the tweeter. Okay this is the tweeter for
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this tweet so I'm gonna call the relationship tweeter
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on this side. Okay I could probably call it user or
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something as well but tweeter is kind of fun.
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00:10:10,844 --> 00:10:13,378
On the other side this is tweet. Okay.
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So this is the tweet that this user has tweeted. Okay.
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00:10:19,119 --> 00:10:22,921
Now notice when you do this if you inspect either one,
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like if you inspect tweets right there,
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it's showing me that the inverse is tweeter.
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So it knows the inder-, inverse right there,
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okay. Now there's something different though about
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this tweets relationship to the tweeter relationship. Cuz,
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there are multiple tweets per Twitter user, right?
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So user could have tweeted hundreds of times. So
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00:10:45,212 --> 00:10:46,911
this basically is multiple things,
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00:10:46,913 --> 00:10:50,548
this is a to-many relationship to use database jargon there
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00:10:50,550 --> 00:10:53,385
are many tweets per user even though there's only one user
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00:10:53,387 --> 00:10:57,455
per tweet. And you define that up here in the inspector,
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00:10:57,457 --> 00:10:58,423
if you have tweet selected.
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00:10:58,425 --> 00:11:01,793
You go here to the type of relationship it is. And
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00:11:01,795 --> 00:11:05,930
you can say it's a too many relationship. And when I do
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00:11:05,932 --> 00:11:09,668
that notice I get this little double arrow right here. Okay?
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00:11:09,670 --> 00:11:13,672
That's telling me that there's many tweets per Twitter user.
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Now, this is gonna show up differently in my code.
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00:11:16,243 --> 00:11:19,678
This one right here is gonna show up in my code, okay,
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this tweet thing that I have, this
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tweet entity is gonna have a var, right here,
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00:11:24,117 --> 00:11:28,386
called tweeter. It's gonna be of type NSManagedObject,
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because I told you all of these entities, this, and
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00:11:31,291 --> 00:11:34,559
this, are gonna show up in your code as NSManagedObject,
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00:11:34,561 --> 00:11:36,227
so that's gonna be the type of this var.
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The type of this var over here is gonna be ns set. Okay?
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00:11:42,235 --> 00:11:45,136
And NSSet I can't remember if we talked about that earlier
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in the quarter but it's very similar to NSArray, okay?
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But it's unordered and unique. Ok, so an NS
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00:11:53,747 --> 00:11:56,881
array can have the same object in it multiple times and
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an NS array is also in order. And in a set,
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00:11:59,686 --> 00:12:02,120
it's just a bunch of objects in there, and
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00:12:02,122 --> 00:12:05,256
if you add in the same object again, it would do nothing.
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00:12:05,258 --> 00:12:06,991
Okay, so it's basically a unique set and
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00:12:06,993 --> 00:12:10,895
there's no order to it's just a big jumble of them. Okay,
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and since these Tweets are basically a big jumble of
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00:12:14,134 --> 00:12:17,168
tweets done by this user in no particular order, that's why
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it's an NS set. Now, there is in Swift a struck called set,
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and is automatically bridged just like NS array,
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00:12:27,180 --> 00:12:28,813
automatically bridged to an array. Okay?
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00:12:28,815 --> 00:12:31,382
So you can think of this as just being a set, but in fact,
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it's an NSSet. Okay? And what's in that set? Of course,
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ManageObject, NSManageObject, cuz these are in there. Okay?
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So it's exactly what you would think. All right? Now.
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There's lots of things you can do, okay, in core data.
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We're gonna focus on a small part of it, but
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00:12:49,603 --> 00:12:51,770
the core of it, which is entities, attributes, and
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00:12:51,772 --> 00:12:54,706
relationships, these things that I just told you about.
255
00:12:54,708 --> 00:12:58,176
Okay. How do you access all this stuff in the code?
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You need an instance of one of these.
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NSManagedObjectContext. You can think of that as kind of
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the window into the world of your database of objects,
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okay? So you need one of these to be able to do anything
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from the database. All right? So how do I get one of these?
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[LAUGH] Okay? I need one of these, how do I get it? Well,
262
00:13:20,767 --> 00:13:23,434
there's really two ways to get it, and you use them kind
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00:13:23,436 --> 00:13:26,404
of about equally. One's not really necessarily preferred
264
00:13:26,406 --> 00:13:29,841
over the other. One of them is when you create your project,
265
00:13:29,843 --> 00:13:31,609
do you remember when we create a project there was a little
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00:13:31,611 --> 00:13:34,078
button at the bottom, there's three switches at the bottom.
267
00:13:34,080 --> 00:13:37,949
One was You, are you gonna do testing or UI testing? And
268
00:13:37,951 --> 00:13:40,418
the other one on the top of the three buttons was
269
00:13:40,420 --> 00:13:44,656
I'm using Core Data. Do you remember that button? Anyway,
270
00:13:44,658 --> 00:13:45,857
it's there, I promise you. And
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00:13:45,859 --> 00:13:49,861
if you click that button when you create your application,
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00:13:49,863 --> 00:13:52,330
then you're going to get a bunch of code
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00:13:52,332 --> 00:13:56,034
Provided to you.. One of which is a method that gives you one
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00:13:56,036 --> 00:14:00,038
of these shared in your whole application. Okay, and
275
00:14:00,040 --> 00:14:02,941
I'm going to talk about how that works in a second.
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00:14:02,943 --> 00:14:05,977
The second way you can get one of these little guys
277
00:14:05,979 --> 00:14:09,180
is to create a U-I managed document, okay?
278
00:14:09,182 --> 00:14:12,350
The U-I managed document has a var on it called managed
279
00:14:12,352 --> 00:14:16,421
object context, which will give you one of these. Okay?
280
00:14:16,423 --> 00:14:19,357
So, I'm going to talk about both of these mechanisms for,
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00:14:19,359 --> 00:14:21,926
for getting this. All right. So, the first one,
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00:14:21,928 --> 00:14:25,363
where you click the switch: When you flip that switch,
283
00:14:25,365 --> 00:14:28,366
you're going to, essentially get some code
284
00:14:28,368 --> 00:14:31,035
put in that AppDelegate.Swift file. Remember
285
00:14:31,037 --> 00:14:34,038
the AppDelegate.Swift? It's one of the files we always
286
00:14:34,040 --> 00:14:35,240
move in to supporting files.
287
00:14:35,242 --> 00:14:37,141
One of the first things I ever do, is okay,
288
00:14:37,143 --> 00:14:41,045
let's take image assets and AppDelegate and info.plist.
289
00:14:41,047 --> 00:14:43,114
Let's move them into a little folder called supporting
290
00:14:43,116 --> 00:14:45,550
files. Well, we haven't looked at that AppDelegate cuz
291
00:14:45,552 --> 00:14:49,420
there's really not much in there at this point but
292
00:14:49,422 --> 00:14:52,757
in there will be a bunch of code for core data, okay,
293
00:14:52,759 --> 00:14:56,127
if you flip that switch. Okay, and one of the things in that
294
00:14:56,129 --> 00:14:58,763
bunch of code is a method called managedObject,
295
00:14:58,765 --> 00:15:00,765
it's a var actually called managedObjectContext.
296
00:15:00,767 --> 00:15:04,102
And all you need to do is call that var and boom, you'll have
297
00:15:04,104 --> 00:15:05,837
a managedObjectContext to the database for
298
00:15:05,839 --> 00:15:09,440
this app. And App Delegate is kinda a global resource but
299
00:15:09,442 --> 00:15:11,542
your database is often a global resource, right?
300
00:15:11,544 --> 00:15:14,712
All your view controllers want to be able to see the data in
301
00:15:14,714 --> 00:15:17,348
the database, so it's reasonable. Now, the way you
302
00:15:17,350 --> 00:15:20,418
get at it, you get this AppDelegate. It's a little,
303
00:15:20,420 --> 00:15:22,687
it seems a little complicated, but it's not too bad.
304
00:15:22,689 --> 00:15:25,924
We're going to call this, this, class method on new
305
00:15:25,926 --> 00:15:29,260
application called Shared Application. And this returns
306
00:15:29,262 --> 00:15:33,331
you the one and only instance of UI application,
307
00:15:33,333 --> 00:15:36,467
which is just a class that represents your app.
308
00:15:36,469 --> 00:15:39,637
Ok now that object, UI application dot shared
309
00:15:39,639 --> 00:15:42,707
application, has a delegate. You all know what delegation
310
00:15:42,709 --> 00:15:47,278
is. It has a delegate. That delegate is that app delegate,
311
00:15:47,280 --> 00:15:51,282
the place where that manage object code got thrown.
312
00:15:51,284 --> 00:15:54,719
So you're going to cast it though as app delegate.
313
00:15:54,721 --> 00:15:57,689
You could do question mark here and then If it comes
314
00:15:57,691 --> 00:16:01,492
backs nil, I'm guess you're SOL you have any database, but
315
00:16:01,494 --> 00:16:04,896
here I'm gonna force cast it because if I can't get this
316
00:16:04,898 --> 00:16:08,066
managed object contacts. Then I can't do anything with my
317
00:16:08,068 --> 00:16:10,902
app, so I'm going to let it crash here for
318
00:16:10,904 --> 00:16:14,339
some reason my app delegate is not my delegate of
319
00:16:14,341 --> 00:16:17,241
my UI application. So anyway, you do this line of code and
320
00:16:17,243 --> 00:16:20,044
this is going to give you back your managed object context.
321
00:16:20,046 --> 00:16:22,046
So, now you have the portal that you need.
322
00:16:22,048 --> 00:16:24,782
To do all the database stuff. Okay? So that's one way to get
323
00:16:24,784 --> 00:16:28,286
this portal. The other way is UIManagedDocument. Okay,
324
00:16:28,288 --> 00:16:31,689
UIManagedDocument is a class it inherits from UIDocument
325
00:16:31,691 --> 00:16:35,059
and it's only job really is to encapsulate a core data
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00:16:35,061 --> 00:16:38,129
database, that's what it does. It encapsulates a core data
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00:16:38,131 --> 00:16:41,866
database, I mean, a file on disk Alright?
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00:16:42,369 --> 00:16:45,036
And, the way you create a UIManagedDocument,
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00:16:45,038 --> 00:16:47,305
UIManagedDocument is actually really easy. And you might
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00:16:47,307 --> 00:16:50,274
ask, why would I ever do that othe
gitextract_9dzbwgkv/
├── README.md
├── download.md
└── subtitles/
├── 1. Course Overview and Introduction to iOS, Xcode, and Swift.srt
├── 10. Core Data.srt
├── 11. Core Data Demo.srt
├── 12. AutoLayout.srt
├── 13. NSTimer and Animation.srt
├── 14. Animation and Core Motion.srt
├── 15. Application Lifecycle, Alerts, CloudKit.srt
├── 16. Notifications and CloudKit.srt
├── 17. Segues, Core Location, and MapKit.srt
├── 18. Persistence.srt
├── 2. Applying MVC.srt
├── 3. More Swift and Foundation Framework.srt
├── 4. Views.srt
├── 5. Interface Builder, FaceView Controller, Gestures, and Multiple MVCs.srt
├── 6. Multiple MVCs, Segues, FaceIt, and View Controller Lifecycle.srt
├── 7. Closures, Extensions, Protocols, Delegation, and ScrollView.srt
├── 8. Multithreading and Text Field.srt
└── 9. Table View.srt
Condensed preview — 20 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (2,680K chars).
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{
"path": "README.md",
"chars": 1444,
"preview": "Developing iOS 9 Apps with Swift 字幕简体中文翻译项目\n---\n\niTunes U 课程地址：[iTunes U/Developing iOS 9 Apps Swift](https://itunes.app"
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]
About this extraction
This page contains the full source code of the CS193P-Translation-Group/Developing-iOS-9-Apps-with-Swift GitHub repository, extracted and formatted as plain text for AI agents and large language models (LLMs). The extraction includes 20 files (2.3 MB), approximately 597.2k tokens. Use this with OpenClaw, Claude, ChatGPT, Cursor, Windsurf, or any other AI tool that accepts text input. You can copy the full output to your clipboard or download it as a .txt file.
Extracted by GitExtract — free GitHub repo to text converter for AI. Built by Nikandr Surkov.