11. Core Data Demo.srt

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[MUSIC]
(音乐)

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Stanford University,
斯坦福大学,

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>> Welcome to Stanford CS193P,
> >欢迎来到斯坦福CS193P,

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developing applications for iOS,
iOS应用程序开发,

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It's winter of 2017,
这是2017年冬天,

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This is lecture number 11 and
这是11号和讲座

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today we're gonna do one gigantic demo,
今天我们要做一个巨大的演示,

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Last time I made you suffer through basically doing
上次我让你遭受基本上做的

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all slides,
所有幻灯片,

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Now, you get to enjoy all demo for the whole time,
现在,你可以享受所有演示了整个时间,

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And it's all gonna be about Core Data and applying all
都是会对核心数据和应用

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the things that we learned in the last lecture into a demo,
我们在上节课学到的演示,

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And then we'll be coming back to the slides, so
然后我们会回到幻灯片,

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let me just give you a heads up of what's happening here,
让我给你一个头这里发生了什么,

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On Friday, we have this other database mechanism for
上周五,我们有这个其他数据库的机制

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storing data in iCloud,
在云存储数据,

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I highly recommen this one, at our Friday section,
我强烈recommen这个,在我们周五部分,

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normal place and time,
正常的地点和时间,

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Monday's a holiday, so
周一的一个节日,所以

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don't show up here on Monday cuz I won't be here,
周一没有出现在这里因为我不会在这里,

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And then next Wednesday, I'll be going over the final
然后下个星期三,我将会在最后

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project requirements, including the rubric, and
项目需求,包括标题和

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also we'll be doing the topic, autolayout,
我们也会做主题,自动布局,

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Now, your assignment five has been
现在,作业5

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posted already, and it's due one
已经发布了,它是由于一个

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week from today before lecture,
星期从今天开始演讲之前,

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So here's Smashtag from last week,
这是Smashtag从上周,

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Remember we have this one MVC where we type in a search
记得我们有这一个MVC输入一个搜索

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string, #Stanford or whatever else,
字符串,#斯坦福或者其他,

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and it pulls down a bunch of tweets,
这一群推拉下,

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Now we're just gonna add another MVC,
现在,我们要添加另一个MVC,

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a core data driven MVC,
一个核心数据驱动的MVC,

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And when this MVC is gonna show all the Twitter users who
当这个MVC会显示所有的Twitter用户

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tweeted all the tweets that are showing in this MVC
在推特上的所有微博显示MVC

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right here,
在这里,

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So, if you type a certain search term like #Stanford,
所以,如果你输入一个特定的搜索词像#斯坦福大学,

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Stanford gets a bunch of tweets,
斯坦福大学被一群微博,

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And then there's gonna be a button on this MVC,
然后会有一个按钮在这个MVC,

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we're gonna put it up in the title bar,
我们要把它的标题栏,

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we're gonna show you how to do that as well,
我们会告诉你怎么做,

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And you're gonna click that button,
你会点击那个按钮,

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It's gonna bring a new MVC with all the users, and
它会带来一个新的MVC的用户,和

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we'll also put in there how many times,
我们也会把多少次,

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how many tweets they tweeted,
多少微博发微博

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When we do that, we're only gonna be looking at the tweets
当我们这样做,我们只会看微博

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that are in this result, this search result right here,
在这个结果,这个搜索结果,

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or that have ever come from typing this search term,
或者曾经来自输入搜索词,

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All right, so this is all gonna be core data,
好吧,这是所有核心数据,

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So we need core data in our app,
所以我们需要核心数据在我们的应用程序,

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When we built Smashtag we didn't click use core data, so
当我们建立Smashtag没有点击使用核心数据,

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we're gonna have to go through the procedures that I talked
我们要办理的手续,我说

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about last time for adding core data to our app,
关于上次的核心数据添加到我们的应用程序,

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And we're gonna do that by creating a dummy
我们要做的,通过创建一个假

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app right here,
应用程序在这里,

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Let's go to New > Project,
让我们去新的>项目时,

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So we're gonna create a dummy project,
所以我们要创建一个虚拟项目,

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you can call this project anything you want,
这个项目你可以叫任何你想要的,

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I'm gonna call it Foo,
我要叫它Foo,

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Just make sure that Use Core Data is clicked right there,
确保使用核心数据点击,

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We can put it anywhere we want cuz we're just gonna turn
我们可以在任何地方把它因为我们要

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around and delete it in a moment,
删除它,

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And you can see that it has created this dummy project,
你可以看到它已经创造了这个虚拟项目,

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And all we're really interested in here is
和所有我们真正感兴趣的

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the code from the AppDelegate that does core data,
的代码在AppDelegate核心数据,

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You can see that this AppDelegate imports CoreData,
你可以看到这个AppDelegate CoreData进口,

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Now we haven't talked about the AppDelegate, and we will,
现在我们还没有谈到在AppDelegate,我们将

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It's part of the application lifecycle,
这是应用程序生命周期的一部分,

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But, for now,
但是,就目前而言,

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all we need to know is that we're gonna go down here and
我们需要知道的是,我们要在这里

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get this stuff or core data,
得到这个东西或核心数据,

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you recognize this from the slides,
你认识这个幻灯片,

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And notice also this applicationWillTerminate calls
注意这个applicationWillTerminate调用

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saveContext,
saveContext,

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SaveContext is one of the Core Data methods that you get for
SaveContext是核心数据的方法得到

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So I'm actually gonna select that as well as all the rest
所以我要选择,以及所有的休息

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free here,
在这里,自由

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of this stuff is marked Core Data right there,
这些被标记的核心数据,

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And I'm just gonna copy it,
我要复制它,

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I'm gonna close this project cuz I don't need it,
我要关闭这个项目因为我不需要它,

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And I'm gonna go over to the AppDelegate in my Smashtag
我要去在AppDelegate Smashtag

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right here,
在这里,

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And you can see it doesn't import core data right there
你可以看到它不导入核心数据

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at the top,
在顶部,

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Nor does applicationWillTerminate call
applicationWillTerminate也不叫

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SaveContext, nor does it have any of other stuff down there,
SaveContext,也没有任何其他的东西,

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So I'm just gonna take that code and paste in here,
所以我要把代码粘贴在这里,

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And this code is generic, it works in all applications,
这代码是通用的,适用于所有应用程序,

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The only thing that's specific about it is this string right
唯一的具体这个字符串是正确的

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here, which tells you the data model, the thing that
,告诉你数据模型,的事情

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describes the schema of your object or in a database,
描述了对象的模式或数据库中,

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Now you notice we have an error right here, that's
现在你注意到我们有一个错误,这是

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because it doesn't recognize NSPeristentContainer,
因为它不认识NSPeristentContainer,

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Because NSPeristentContainer is in a different framework
因为NSPeristentContainer是在一个不同的框架

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than UIKit, it's in CoreData,
比UIKit CoreData,

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So every time you're using CoreData in a swift file,
所以每次你使用CoreData在迅速文件中,

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you need to import CoreData or it won't recognize in this
你需要进口CoreData也不会承认这一点

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managed object or any of the other symbols from core data,
管理对象或任何其他符号的核心数据,

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So that's one thing we have to do that we use Core Data
这是我们必须做的一件事,我们使用核心数据

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The other one is actually create the data model itself,
另一个是实际创建数据模型本身,

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button did,
按钮,

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And that we do with File > New > File, so
我们与File > New >文件,

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I'm gonna go File > New > File,
点击File > New >文件,

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And we, normally we're picking things up here but we're gonna
我们通常我们捡东西但我们会

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scroll down to where it says Core Data and pick Data Model,
向下滚动到核心数据和数据模型,

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We don't want Mapping Model, we want Data Model,
我们不想映射模型,数据模型,

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This is just gonna be that thing where we describe all
这只是将那件事我们描述所有的地方

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our entities and attributes,
我们的实体和属性,

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And we can call it anything we want,
我们可以叫它任何我们想要的,

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Just to be kind of different I'm gonna call it Smash,
只是有点不同的我要叫它打碎,

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That's gonna be the name of my Data Model,
这是要我的名字数据模型,

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And I'm not gonna put in Supporting Files,
和我不会放在支持文件,

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I'm gonna put it in Smashtag in a higher,
我要把它放在Smashtag更高,

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this level up here and click Create,
这个水平并单击创建、

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And here it is,
是这样的,

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You can probably recognize this, right?
你可以认识到这一点,对吧?

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This is our entities and attributes,
这是我们的实体和属性,

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We haven't put any of them in there,
我们还没有把其中的任何一个,

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Now, since I call this Smash and not Foo,
现在,既然我称之为粉碎而不是Foo,

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I've to go back to my AppDelegate and
我回到AppDelegate和

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change this Foo string in here to be Smash,
改变这个字符串Foo被粉碎,

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So I've pretty much now reproduced everything that
所以我现在几乎复制一切

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the use core data button would do,
使用核心数据按钮,

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The only difference would be the use core data would have
唯一不同的是使用核心数据

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called my xcdatamodeld file,
叫我xcdatamodeld文件,

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It would have called it Smashtag,
它会称之为Smashtag,

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cuz that's the name of my app, but I like to call it Smash,
因为这是我的程序的名字,但是我喜欢叫它打碎,

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All right, so now that we have this nice data model file,
好了,现在我们有这个很好的数据模型文件,

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let's go ahead and create our schema,
让我们创建模式,

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Now, I'm gonna do this really quick because I already showed
现在,我要做这个很快,因为我已经显示

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you how to do all this which you can just watch it
你如何做这一切,你可以看它

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happening real fast,
发生的很快,

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I'm not gonna show you anything that I didn't show
我不会告诉你任何我没有展示

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you in the last lecture,
你的最后一课,

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I'm gonna start by adding an entity down here at
下面我要开始通过添加一个实体

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All right, this entity I'm going to rename it,
好吧,这个实体我要重命名它,

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the bottom,
底部,

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And I'm gonna do tweets and Twitter users cuz I'm gonna
我要做微博和推特用户因为我要

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have that table that follows Twitter users,
那张桌子,Twitter用户,

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But obviously those Twitter users are determined by
但显然这些Twitter用户是由

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a bunch of tweets, so those are two entities I need,
一群微博,所以我需要这两个实体,

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So let's put Tweet here first, and
所以我们先把推特这里,

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we'll add attributes for the tweet,
我们将添加属性的微博,

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I'm gonna add them by clicking this little plus right here,
我要把它们通过点击这个小加在这里,

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So we have the Text Attribute which is a String,
我们是一个字符串的文本属性,

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We have our tweets, what if we search for
我们有微博,如果我们在搜寻什么

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#Stanford twice in a row?
#斯坦福连续两次吗?

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We might get the same tweet back,
我们可能会得到同样的推回来,

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And we want our database to have unique tweets,
我们希望我们的数据库有独特的微博,

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we don't wanna every time we search we're getting more and
我们不想每次我们搜索我们获得更多

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more of the same tweet in there,
更多相同的微博,

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So I need some sort of unique
所以我需要某种独一无二的

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attribute in my database which is gonna a string,
属性在我的数据库是一个字符串,

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Luckily, the Twitter info that comes in the Twitter
幸运的是,Twitter的Twitter信息

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framework, it has a unique identifier in there for
框架,它有一个惟一的标识符

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tweets so it'll be really easy to set that,
微博所以就很容易,

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And I'm not gonna use this but for
我不会使用这个但

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example, if I wanted a created attribute it would be a date,
例子,如果我想要一个创建属性,那将是一个日期,

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I would just click Date,
我就点击日期,

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I'm putting this in here cuz I just wanna show you what
我将在这里因为我想告诉你什么

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it's like to set a date in code,
就像在代码中设定一个日期,

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This looks slightly tricky,
这看起来有点棘手,

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So I'm gonna add another, or
所以我要添加另一个,或

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actually we could look here in the Editor Style,
实际上我们可以看这里的编辑风格,

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So this is the exact same thing here in
这是相同的东西在这里

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the Editor Style,
编辑风格,

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When you're in Editor Style,
当你在编辑风格,

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you're almost always gonna have your inspector
你几乎总是会有你的检查员

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open right here so that you can click on things and
打开这里,这样您就可以点击,

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change their types and things like that,
改变他们的类型和类似这样的事情,

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I'm gonna create another entity here and it's going to
我要创建另一个实体,它会

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be our Twitter user, I'm gonna call that Twitter user,
是我们的Twitter用户,我要调用Twitter用户,

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00:07:33,253 --> 00:07:34,752
And notice when I move these around,
注意当我移动这些,

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00:07:34,821 --> 00:07:37,422
it moves it around whatever other entities there are,
它在任何其他实体,

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00:07:37,491 --> 00:07:39,357
And I'm gonna be connecting these two and
我要这两个和连接

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00:07:39,425 --> 00:07:42,160
creating a relationship, and you're gonna see it's gonna
创建一个关系,你会看到它

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00:07:42,228 --> 00:07:43,829
keep drawing it as we draw there,
保持它画成画,

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00:07:44,864 --> 00:07:46,697
So let's add some attributes here,
让我们添加一些属性,

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00:07:46,766 --> 00:07:48,200
So I'm gonna click Add Attribute,
所以我要点击添加属性,

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Sorry,
对不起,

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00:07:57,544 --> 00:07:59,244
It's not deleting, let's go back to Editor Style here,
不是删除,让我们回到编辑风格,

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By the way, I do notice sometimes that when selecting
顺便说一下,我确实注意到有时,当选择

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things, it's not always that great,
事情,这并不总是很好,

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it doesn't do that great a job,
没有伟大的工作,

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00:08:13,726 --> 00:08:15,927
I'm not sure what it is about the data modeler that makes it
我不确定这是什么使得它的数据建模师

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00:08:15,996 --> 00:08:17,629
that way, but you'll click on something,
这样,但是你会点击,

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00:08:17,697 --> 00:08:19,564
and it doesn't click on that thing,
也不会点击它,

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00:08:19,633 --> 00:08:21,232
it clicked the entity or something else,
它点击实体或别的东西,

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00:08:21,300 --> 00:08:23,268
So there is an example where I was clicking on that
这是一个例子,我是点击

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00:08:23,336 --> 00:08:25,503
attribute, but it wouldn't let me delete it,
属性,但它不让我删除它,

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00:08:25,572 --> 00:08:27,171
Here I have Twitter user chosen,
在这里我有推特用户选择,

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00:08:27,240 --> 00:08:28,539
hopefully add attribute,
希望添加属性,

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00:08:28,608 --> 00:08:30,741
Yes, it adds it to the Twitter user,
是的,它将其添加到Twitter用户,

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00:08:30,810 --> 00:08:34,078
The only attributes I'm gonna have on my Twitter user
唯一我要对我的Twitter用户属性

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are the handle, that's your @whatever, and then your name,
处理,这是你的@whatever,然后你的名字,

195
00:08:40,153 --> 00:08:43,021
And those are both going to be strings, so
这些都是字符串,所以

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00:08:43,089 --> 00:08:46,524
we'll go over here and make this be of type string,
我们去这里,这是string类型的,

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00:08:46,593 --> 00:08:51,595
And we'll also make the handle be type string,
和我们也会使处理字符串类型,

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00:08:51,664 --> 00:08:54,499
So that's it for the attributes,
这是它的属性,

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00:08:54,567 --> 00:08:56,834
And the only thing we have left to do is the relationship
和我们唯一剩下要做的就是关系

200
00:08:56,903 --> 00:08:57,735
between these two,
在这两个之间,

201
00:08:57,804 --> 00:08:59,437
And I'm gonna hold down Ctrl and
我要按住Ctrl和

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00:08:59,506 --> 00:09:02,540
drag between the two right here,
拖两个在这里,

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00:09:02,608 --> 00:09:06,544
And you see it creates a new relationship on both sides,
你看到它创建一个新的关系双方,

204
00:09:06,613 --> 00:09:07,344
But we don't want that,
但是我们不希望这样,

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the Twitter user here, this relationship is the tweets
这里的Twitter用户,这种关系是tweet

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00:09:10,684 --> 00:09:12,850
that this Twitter user has tweeted,
这个推特用户写道:,

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00:09:12,919 --> 00:09:15,887
And for the tweet, this relationship is the tweeter,
微博,这种关系是推特,

208
00:09:16,990 --> 00:09:19,157
the person who tweeted it,
的人在推特上,

209
00:09:19,226 --> 00:09:21,826
This tweets relationship right here we know is a "too many"
这个微博关系我们知道是“太多”

210
00:09:21,895 --> 00:09:24,729
relationship because a Twitter user gonna have multiple
因为Twitter用户将有多个的关系

211
00:09:24,798 --> 00:09:25,930
tweets,
微博,

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00:09:25,999 --> 00:09:27,599
That's why get the little double arrow there,
这就是为什么小双箭头,

213
00:09:29,703 --> 00:09:32,403
That's our entire data model that we need now,
这就是我们现在需要我们整个数据模型,

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00:09:32,472 --> 00:09:33,637
For your homework assignment,
你的家庭作业,

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00:09:33,706 --> 00:09:35,540
you're gonna need more things in here,
你需要更多的事情在这里,

216
00:09:35,609 --> 00:09:37,742
This is not gonna be sufficient to the task, so
这是任务,不会足以

217
00:09:37,811 --> 00:09:40,378
you're gonna have to add some more stuff,
你需要添加一些更多的东西,

218
00:09:40,447 --> 00:09:43,914
But for our simple example, this is all we need,
但是对于我们的简单的例子,这是我们所需要的,

219
00:09:43,983 --> 00:09:47,852
Now, we know that we wanna access all this stuff,
现在,我们知道我们想要访问所有这些东西,

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00:09:47,921 --> 00:09:50,988
not using value in for key and set value for key,
没有使用价值为键,键和设置值

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00:09:51,057 --> 00:09:52,256
We wanna have subclasses,
我们想有子类,

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00:09:52,325 --> 00:09:53,958
a subclass called TwitterUser and a club,
一个子类TwitterUser和一个俱乐部,

223
00:09:54,026 --> 00:09:55,392
subclass called Tweet,
子类称为Tweet,

224
00:09:55,461 --> 00:09:57,061
And we want them to have the vars for
我们希望他们有var

225
00:09:57,130 --> 00:09:59,063
all of these attributes and relationships,
所有这些属性和关系,

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00:09:59,132 --> 00:10:02,099
And so, we need that code to be generated,
所以,我们需要生成代码,

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00:10:02,168 --> 00:10:04,769
And the way we do that is we just select the answer to,
我们的方法是我们选择的答案,

228
00:10:04,838 --> 00:10:07,472
you see I've selected Tweet right here, entity Tweet,
你看到我选定的Tweet,实体推特,

229
00:10:07,541 --> 00:10:09,040
And you go down here to Codegen, and
你去下面Codegen,

230
00:10:09,109 --> 00:10:11,442
this says, by default, Class Definition,
这个说,默认情况下,类定义,

231
00:10:11,511 --> 00:10:13,244
That means that it's done it,
这意味着完成它,

232
00:10:13,313 --> 00:10:15,814
it has generated a class called tweet, and
它生成一个类称为tweet,

233
00:10:15,882 --> 00:10:17,782
it's gonna work with all the vars in relationship,
它会处理所有的var的关系,

234
00:10:17,851 --> 00:10:20,184
But that's not actually what we want,
但实际上这并不是我们想要的,

235
00:10:20,253 --> 00:10:22,987
We want to pick this one, where it only
我们想选这个,它只在哪里

236
00:10:23,056 --> 00:10:27,826
creates an extension to tweet that add to the vars stuff,
创建一个扩展tweet添加到,var的东西,

237
00:10:27,894 --> 00:10:30,127
That's because we wanna write the class tweet and
这是因为我们想要写类微博和

238
00:10:30,196 --> 00:10:31,796
be able to put our own code in there,
能够把我们自己的代码,

239
00:10:31,865 --> 00:10:35,066
It's very common to one will write the class herself
是很常见的一个将编写自己的类

240
00:10:35,134 --> 00:10:36,100
the main class,
主类,

241
00:10:36,169 --> 00:10:38,069
But you still want the var magic, so
但你仍然希望var魔法,所以

242
00:10:38,137 --> 00:10:40,104
you want those extensions in there,
你想要这些扩展,

243
00:10:40,173 --> 00:10:42,840
Another thing that I didn't really mention in lecture, and
另一件事我没有提到的讲座,和

244
00:10:42,909 --> 00:10:45,376
really, I don't think really matters unless you're in
真的,我不认为真正重要的,除非你在

245
00:10:45,445 --> 00:10:47,845
a workspace like we are, you know, we have Twitter and
一个工作区,你知道,我们有Twitter和

246
00:10:47,914 --> 00:10:50,248
smash dot org space, is this module name right here,
打碎点组织空间,这里的模块名称,

247
00:10:50,317 --> 00:10:51,950
If you don't have anything in here,
如果你在这里,没有什么

248
00:10:52,018 --> 00:10:54,719
then it's gonna use a global namespace for these classes,
然后它会使用这些类的全局名称空间,

249
00:10:54,788 --> 00:10:57,055
like tweet, so it's gonna call the class tweet,
喜欢微博,所以它会调用类微博,

250
00:10:57,123 --> 00:11:00,391
But actually, we already have a Twitter,tweet, and
但实际上,我们已经有一个推特,推特,

251
00:11:00,460 --> 00:11:02,960
now we're gonna have Smashtag,tweet,
现在我们要有Smashtag,推特,

252
00:11:03,029 --> 00:11:06,564
So we want to change this to be current product module,
所以我们要改变这是当前的产品模块,

253
00:11:06,632 --> 00:11:07,532
So don't forget this,
所以不要忘记这个,

254
00:11:08,702 --> 00:11:10,367
Wake up, if you're not paying attention,
醒来,如果你不注意,

255
00:11:10,436 --> 00:11:12,069
If you don't put this right here,
如果你不放这里,

256
00:11:12,138 --> 00:11:14,772
you're likely to get tons of errors,
你可能会得到大量的错误,

257
00:11:14,841 --> 00:11:17,074
All kinds of conflicting class names,
各种冲突的类名,

258
00:11:17,143 --> 00:11:20,077
and even if your app builds, it won't run,
即使你的应用构建,它不会跑,

259
00:11:20,146 --> 00:11:21,145
Terrible things will happen, so
可怕的事情会发生,所以

260
00:11:21,214 --> 00:11:22,446
you definitely wanna do this,
你一定要这样做,

261
00:11:22,515 --> 00:11:24,782
I don't believe you need to do this if you're not in
我不相信你不需要这样做,如果你在

262
00:11:24,851 --> 00:11:25,416
a workspace,
一个工作区,

263
00:11:25,485 --> 00:11:27,552
I think if you just have an app by itself,
我想,如果你只有一个应用程序本身

264
00:11:27,621 --> 00:11:30,288
you can leave that unset, and it'll work fine,
你可以把设置,它会工作很好,

265
00:11:31,524 --> 00:11:34,292
So that, we did that for tweet right here, so
因此,我们在这里做了推特,所以

266
00:11:34,360 --> 00:11:36,261
let's do it now for Twitter user,
让我们为Twitter用户,现在就做

267
00:11:36,329 --> 00:11:38,929
Twitter user is default in class definition,
Twitter用户默认的类定义,

268
00:11:38,998 --> 00:11:41,699
I want that to be extension also, and of course,
我也想要,扩展,当然,

269
00:11:41,768 --> 00:11:45,336
I want current product module there,
我想当前的产品模块,

270
00:11:45,404 --> 00:11:48,305
So that's all we need to do, and behind the scenes,
这就是我们要做的,在幕后,

271
00:11:48,374 --> 00:11:51,408
Xcode has furiously written out this extension to make
Xcode疯狂地写了这个扩展

272
00:11:51,477 --> 00:11:52,310
the vars work,
增值的工作,

273
00:11:52,378 --> 00:11:54,946
But we have said that we're gonna write the class,
但我们已经说过,我们要编写的类,

274
00:11:55,014 --> 00:11:57,348
So let's do that, let's create the class for
让我们这样做,让我们创建类

275
00:11:57,417 --> 00:11:58,616
twitter user and for tweets,
twitter用户微博,

276
00:11:58,685 --> 00:12:00,918
So we're gonna go to File > New > File,
所以我们要去File > New >文件,

277
00:12:00,987 --> 00:12:04,255
it's just how we create any class, it's no different than
这只是我们如何创建任何类,它没有不同

278
00:12:04,324 --> 00:12:08,092
any other class we've created, Cocoa Touch Class,
我们创建其他类,可可触摸类,

279
00:12:08,161 --> 00:12:10,427
It's not a TableViewController,
这不是一个表,

280
00:12:10,496 --> 00:12:14,698
it's an NSManagedObject, so we go down here, it's in somewhat
这是个NSManagedObject,我们去这里,它在某种程度上

281
00:12:14,767 --> 00:12:19,103
alphabetical order, so, or is it here, NSManagedObject,
字母顺序排列的,所以,还是这里,NSManagedObject,

282
00:12:19,172 --> 00:12:21,739
We know that Twitter user and tweet are representing
我们知道Twitter用户和微博是代表

283
00:12:21,808 --> 00:12:23,607
the database as NSManagedObjects or
数据库作为nsmanagedobject或

284
00:12:23,676 --> 00:12:26,010
subclasses thereof, which we're creating,
我们正在创建的子类,,

285
00:12:26,079 --> 00:12:29,847
So we'll create the tweet one first and we hit Next,
我们将创建推一分之一和冲击下,

286
00:12:29,916 --> 00:12:31,282
It says, where do you wanna put it, and
它说,你想把它放在哪里,

287
00:12:31,350 --> 00:12:33,718
we'll put it in the same place as everything else,
我们会把它放在其他地方一样,

288
00:12:33,787 --> 00:12:36,821
And here it is, we know that we're gonna have an error here
是这样的,我们知道,我们会有一个错误

289
00:12:36,890 --> 00:12:40,124
immediately once this thing gets around to building that,
马上这个建筑,

290
00:12:40,193 --> 00:12:41,792
and that's the NSManagedObject,
的NSManagedObject,

291
00:12:41,861 --> 00:12:45,095
It's not gonna identify, it's not gonna know what that is
它不会识别,不会知道那是什么

292
00:12:45,164 --> 00:12:47,132
until we say import CoreData,
直到我们说进口CoreData,

293
00:12:48,801 --> 00:12:52,036
Don't forget this little piece in your subclass,
不要忘记这一小段子类,

294
00:12:52,105 --> 00:12:55,273
But now we can put anything we want inside these curly
但是现在我们可以把任何我们想要在这些花

295
00:12:55,341 --> 00:12:57,976
braces, and we're going to put a method in there,
牙套,我们将把一个方法,

296
00:12:59,379 --> 00:13:02,347
So let's do the same thing here for Twitter user,
让我们为Twitter用户做同样的事,

297
00:13:04,117 --> 00:13:06,851
Twitter user, in the same way,
Twitter用户,以同样的方式,

298
00:13:06,919 --> 00:13:10,688
put everything in the same place,
把一切都在同一个地方,

299
00:13:10,756 --> 00:13:15,193
Here it is, let's import CoreData,
在这里,我们进口CoreData,

300
00:13:15,261 --> 00:13:19,096
Now when you're first creating your model file and
现在当你第一次创建文件和模型

301
00:13:19,165 --> 00:13:21,198
you choose that extension thing, and
你选择扩展的事情,

302
00:13:21,267 --> 00:13:24,435
hopefully you remember to do current project model, and
希望你记住当前项目模型,

303
00:13:24,504 --> 00:13:26,503
all that stuff, the first time you build, and
所有的东西,你第一次构建

304
00:13:26,572 --> 00:13:30,007
I'm gonna build here, you might get some errors,
我要建在这里,你可能会得到一些错误,

305
00:13:30,076 --> 00:13:33,411
We didn't get any of the kind of errors that you get from
我们没有得到任何的错误,你得到的

306
00:13:33,480 --> 00:13:35,713
things being out of whack, but if things are out of whack,
事情都是不正常的,但如果不正常,

307
00:13:35,781 --> 00:13:38,115
one thing you can do is go up to the product menu,
你可以做的一件事就是去产品菜单,

308
00:13:38,184 --> 00:13:40,518
and clean, just clean everything out,
和清洁,清洁,

309
00:13:40,586 --> 00:13:43,087
That'll cause XCode to regenerate those extensions,
这将导致XCode再生这些扩展,

310
00:13:43,156 --> 00:13:44,188
for example,
例如,

311
00:13:44,256 --> 00:13:48,225
You can even hold down Option when you go to the Product
你甚至可以按住选择当你去产品

312
00:13:48,294 --> 00:13:50,594
menu and then Clean Build Folder,
菜单,然后清洁建立文件夹,

313
00:13:50,663 --> 00:13:52,997
And that will clean out all your drive data and
这将清除所有的数据和开车

314
00:13:53,066 --> 00:13:55,466
rebuild absolutely everything,
重建一切,

315
00:13:55,534 --> 00:13:56,668
So, those are options,
所以,这些都是选择,

316
00:13:56,736 --> 00:13:58,536
And sometimes those are options just to do anytime
有时这些选项只是随时去做

317
00:13:58,604 --> 00:14:01,372
something's kinda not really working right,
有点不正常工作,

318
00:14:01,441 --> 00:14:03,207
Now we do have some errors, though, let's click and
现在我们有一些错误,让我们点击

319
00:14:03,275 --> 00:14:05,175
see what this error is right here,
看看这个错误是在这里,

320
00:14:05,244 --> 00:14:06,010
What is this saying?
这是什么意思吗?

321
00:14:06,078 --> 00:14:08,946
It's saying cannot convert value tweet to specified
它说不能推到指定转换值

322
00:14:09,015 --> 00:14:10,981
value tweet,
tweet价值,

323
00:14:11,050 --> 00:14:13,150
Can anyone see what might be the problem with this line
谁能看到这条线可能是什么问题

324
00:14:13,219 --> 00:14:13,818
of code right here?
的代码呢?

325
00:14:17,290 --> 00:14:19,823
>> Exactly,
> >,

326
00:14:19,892 --> 00:14:23,627
Yes, this is saying tweet, it doesn't know which one we
是的,这是说推特,它不知道我们哪一个

327
00:14:23,696 --> 00:14:27,532
want, twitter,tweet or the smashtag,tweet,
想要的,推特,推特或smashtag,推特,

328
00:14:27,600 --> 00:14:31,502
So we have to, in Swift, fully specify which one we want,
所以我们必须迅速,完全指定哪一个我们想要的,

329
00:14:31,571 --> 00:14:34,572
So this one is the twitter,tweet from our
这一个是推特,推特从我们

330
00:14:34,640 --> 00:14:35,339
old code,
旧代码,

331
00:14:35,407 --> 00:14:36,807
And once we fix that,
一旦我们解决这个问题,

332
00:14:36,876 --> 00:14:41,045
then now it knows what we're talking about and all is well,
然后现在知道我们讨论的是一切都很好,

333
00:14:42,982 --> 00:14:43,948
All right, so
好吧,那么

334
00:14:44,017 --> 00:14:46,884
now we've really got our core data stuff all ready to go,
现在我们真的有我们的核心数据的东西都准备好了,

335
00:14:46,953 --> 00:14:50,922
We've got the classes, we've got our data model explained,
我们的类,我们有我们的数据模型解释说,

336
00:14:50,990 --> 00:14:52,289
all that stuff,
所有的东西,

337
00:14:52,358 --> 00:15:00,598
What we're gonna do next is have our main MVC right here,
接下来我们要做的是让我们的主要MVC,

338
00:15:00,667 --> 00:15:05,136
Every time it fetches tweets,
每次获取tweet,

339
00:15:05,205 --> 00:15:12,776
we're gonna have it put that tweet in the database,
我们会把它推在数据库中,

340
00:15:12,845 --> 00:15:15,012
Once it loads up the database, then we can build this other
一旦加载数据库,然后我们可以建立其他

341
00:15:15,080 --> 00:15:16,981
MVC that will query the database,
MVC将查询数据库,

342
00:15:17,049 --> 00:15:18,916
So this is gonna be kind of the loading one,
所以这是装运,

343
00:15:18,984 --> 00:15:20,318
That's gonna be the querying one,
要查询的,

344
00:15:20,386 --> 00:15:23,854
Now, I might be quite tempted to add this code to
现在,我可能会很想将这段代码添加到

345
00:15:23,923 --> 00:15:27,357
TweetTableViewController,sw- ift,
TweetTableViewController sw -界面张力,

346
00:15:27,426 --> 00:15:29,627
Remember the thing we spent the last lecture doing all
还记得我们上节课做度过的

347
00:15:29,695 --> 00:15:30,728
this wonderful stuff?
这美好的东西呢?

348
00:15:30,797 --> 00:15:33,298
This would be an obvious place, for example in search
这将是一个明显的地方,例如在搜索

349
00:15:33,366 --> 00:15:35,599
for tweets where I'm getting the tweets back,
推,我推回来了,

350
00:15:35,668 --> 00:15:38,669
this would be an obvious place to load up the database,
这将是一个明显的地方加载数据库,

351
00:15:38,738 --> 00:15:41,472
However, I don't wanna do that here,
然而,在这里我不想这样做,

352
00:15:41,541 --> 00:15:43,674
And why don't I wanna do that here?
在这里,我想为什么不这样做呢?

353
00:15:43,743 --> 00:15:46,577
Because I have a perfectly good tweet
因为我有一个完美的tweet

354
00:15:46,646 --> 00:15:50,815
table view controller here, an awesome MVC, very reusable,
表视图控制器,一个了不起的MVC,可重用,

355
00:15:50,884 --> 00:15:53,518
You give it a search term, it'll load up with tweets,
你给它一个搜索词,它会加载微博,

356
00:15:53,586 --> 00:15:55,219
I don't really wanna pollute it and
我不太想和污染它

357
00:15:55,287 --> 00:15:58,823
make it non-reusable by tying it to my data model here,
使它不可重复使用的,把我的数据模型,

358
00:15:58,892 --> 00:16:00,892
by making it a core data thing,
通过它的核心数据,

359
00:16:02,395 --> 00:16:05,629
So how do I resolve that conundrum where I wanna keep
所以我怎么解决这个难题,我想保持

360
00:16:05,698 --> 00:16:06,497
this thing reusable,
这个东西可重用,

361
00:16:06,566 --> 00:16:09,600
but I still need to put this stuff in the database?
但是我还需要把这些东西放在数据库吗?

362
00:16:09,668 --> 00:16:13,938
The answer is, I'm gonna subclass this controller,
答案是,我要子类这个控制器,

363
00:16:14,006 --> 00:16:17,308
I'm gonna make another MVC that is going to inherit
我要让另一个MVC继承

364
00:16:17,376 --> 00:16:19,944
all the capabilities of this nice generic one, and
这个通用的所有功能,

365
00:16:20,013 --> 00:16:21,145
add the core data stuff,
添加的核心数据,

366
00:16:22,682 --> 00:16:26,850
So I'm just gonna go File > New File,
所以我要去文件>新建文件,

367
00:16:26,919 --> 00:16:30,854
Cocoa Touch class, I'm gonna make it not a subclass of any
可可触摸类,我要让它没有的一个子类

368
00:16:30,923 --> 00:16:34,324
iOS class, but a subclass of TweetTableViewController,
iOS类,但是TweetTableViewController的子类,

369
00:16:34,393 --> 00:16:36,627
This is my nice generic reusable one,
这是我漂亮的通用的可重用的一个,

370
00:16:36,696 --> 00:16:37,861
I'm gonna make this a subclass of that,
我要让这个的一个子类,

371
00:16:37,930 --> 00:16:42,533
I'm gonna call it SmashTweetTableViewController,
我要叫它SmashTweetTableViewController,

372
00:16:42,602 --> 00:16:45,536
Cuz it uses my smash data model,
因为它使用我粉碎数据模型,

373
00:16:45,605 --> 00:16:48,138
So I'm just gonna create that, here we go,
所以我要创建,我们开始吧,

374
00:16:48,207 --> 00:16:51,542
put it in the same place as always other things,
把它放在同一个地方一如既往,

375
00:16:51,611 --> 00:16:52,810
I mean we're gonna just delete all these code out here,
我的意思是我们会删除所有这些代码,

376
00:16:52,811 --> 00:16:54,010
Here it is,
在这里,

377
00:16:54,079 --> 00:16:56,980
I always do that just to make it clearer to you what I'm
我总是这样做只是为了让你我更清晰

378
00:16:57,049 --> 00:16:58,816
actually adding in this things,
加入这个东西,

379
00:16:58,884 --> 00:17:02,086
So I have this SmashTweetTableViewController
所以我有这个SmashTweetTableViewController

380
00:17:02,155 --> 00:17:05,055
and I can go to my story board for example and
我可以去我的故事板和例子

381
00:17:05,124 --> 00:17:06,890
select this controller,
选择这个控制器,

382
00:17:06,959 --> 00:17:07,892
And go to Identity,
去身份,

383
00:17:07,961 --> 00:17:10,661
and instead of making it a TweetTableViewController,
而不是让它TweetTableViewController,

384
00:17:10,729 --> 00:17:14,698
I'm gonna make it a SmashTweetTableViewController,
我要让它SmashTweetTableViewController,

385
00:17:14,767 --> 00:17:17,234
So now, this is going to do all the things that
现在,这是要做的所有的事情

386
00:17:17,303 --> 00:17:18,802
TweetTableViewController does,
TweetTableViewController,

387
00:17:18,871 --> 00:17:22,239
plus anything I put in this sub class,
加上我放在这个接头类,

388
00:17:22,308 --> 00:17:25,642
Now, unfortunately, we didn't
现在,不幸的是,我们没有

389
00:17:25,711 --> 00:17:29,614
get all the way to designing our generic reusable one,
得到所有我们通用的可重用设计,

390
00:17:29,682 --> 00:17:32,249
so that it was really nice and subclassable,
所以这是很好的和subclassable,

391
00:17:32,318 --> 00:17:35,253
Specifically, it will be really hard to subclass search
具体地说,它将很难子类搜索

392
00:17:35,321 --> 00:17:39,923
for tweets and then get inside here, in this closure and
tweet,然后进入这里,关闭和

393
00:17:39,992 --> 00:17:42,026
do something when these tweets happen,
做一些当这些tweet发生,

394
00:17:42,095 --> 00:17:44,729
So I'm gonna make my generic TweetTableViewController
所以我要让我的通用TweetTableViewController

395
00:17:44,798 --> 00:17:46,130
a little more subclassable,
更subclassable

396
00:17:46,198 --> 00:17:49,099
What I'm gonna do is take this code right here and
我要做的就是把这个代码

397
00:17:49,168 --> 00:17:50,968
make a little method out of it,
做一个小方法,

398
00:17:51,037 --> 00:17:53,171
insert tweets I'm gonna call it,
插入微博我要叫它,

399
00:17:55,541 --> 00:17:59,477
Okay, I'm just gonna create a new method called insertTweets
好的,我要创建一个名为insertTweets的新方法

400
00:17:59,545 --> 00:18:02,980
that's gonna do what that code I just cut out there is,
这是要做什么,代码我就删掉,

401
00:18:03,048 --> 00:18:04,414
we'll put it up here,
我们会把它放在这里,

402
00:18:04,483 --> 00:18:09,253
Func insertsTweets, it can take some new tweets
Func insertsTweets,它可以采取一些新的tweet

403
00:18:09,321 --> 00:18:13,824
which is gonna be in array of Twitter,tweet,
会在数组的推特,推特,

404
00:18:13,893 --> 00:18:16,861
It's gonna have that same code in there, obviously I don't
它会有相同的代码,很显然我不喜欢

405
00:18:16,929 --> 00:18:19,830
need this weak self business here, because I'm not inside
需要这个弱自我业务在这里,因为我不是在里面

406
00:18:19,899 --> 00:18:22,200
the closure here, and it's going to do it,
关闭,它会这样做,

407
00:18:24,070 --> 00:18:26,737
I'm gonna leave this essentially internal,
我要离开这个内部,

408
00:18:26,805 --> 00:18:28,906
remember that in default internal,
记住,在默认的内部,

409
00:18:28,974 --> 00:18:31,542
which means it can be overwritten or called,
这意味着它可以被覆盖或叫,

410
00:18:31,611 --> 00:18:32,710
If I made that private,
如果我做了,私人,

411
00:18:32,779 --> 00:18:36,346
subclasses would not be able to overwrite it,
子类不能覆盖它,

412
00:18:36,415 --> 00:18:39,616
Unfortunately there's nothing like protected in Swift where
不幸的是,没有什么比保护在斯威夫特

413
00:18:39,685 --> 00:18:42,586
it's like subclassers can override it but people can't
就像子类可以重写,但人不能

414
00:18:42,655 --> 00:18:46,424
call it, unfortunately there's no such thing as that,
称呼它,不幸的是,没有这种东西,

415
00:18:46,492 --> 00:18:50,260
All right, so we have to leave this internal and but now
好了,所以我们不得不离开这个内部和现在

416
00:18:50,329 --> 00:18:54,364
I can take this method in my subclass here and override it,
我可以把这个方法子类重写它,

417
00:18:54,433 --> 00:18:56,733
So I just put it here and say override, so
所以我就把它放在这里说覆盖,所以

418
00:18:56,802 --> 00:18:59,470
Swift knows that I'm overriding this thing,
迅速知道我重写这个东西,

419
00:18:59,539 --> 00:19:01,839
Then I'm gonna let Super do its work,
然后我要让超级做其工作,

420
00:19:04,244 --> 00:19:07,745
And then I'm going to call a method on myself,
然后我要对自己调用一个方法,

421
00:19:09,782 --> 00:19:18,389
updateDatabase(with newTweets), all right?
updateDatabase(newTweets)?

422
00:19:18,458 --> 00:19:22,893
And that's going to update my database, so I'm gonna have
要更新我的数据库,所以我要拥有的

423
00:19:22,961 --> 00:19:27,531
a private func here called updateDatabase (with tweets),
一个私人func叫updateDatabase(微博),

424
00:19:27,600 --> 00:19:30,167
it's gonna be a Twitter,tweet,
它会是一个推特,推特,

425
00:19:30,235 --> 00:19:36,373
Sorry, I keep hitting this tiny button right there,
对不起,我一直打这个小按钮,

426
00:19:36,442 --> 00:19:40,678
That's just going to put these tweets into Core Data,
就是要把这些tweet核心数据,

427
00:19:40,746 --> 00:19:43,881
And of course it's complaining because import Twitter and
当然这是抱怨,因为Twitter和进口

428
00:19:43,950 --> 00:19:46,416
I'm starting using Twitter now,
我现在开始使用Twitter,

429
00:19:46,485 --> 00:19:47,935
I might as well put it now import CoreData because this
我现在不妨把它导入CoreData因为这

430
00:19:47,936 --> 00:19:49,386
By the way,
顺便说一下,

431
00:19:49,455 --> 00:19:52,189
SmashTweetTableViewController is obviously is
SmashTweetTableViewController显然是

432
00:19:52,257 --> 00:19:55,292
going to be doing a lot of core data stuff as well,
要做很多核心数据的东西,

433
00:19:55,361 --> 00:19:56,960
Everyone see what I did there?
每个人都明白我在做什么?

434
00:19:57,029 --> 00:20:00,298
I just subclass this and I'm putting all my smash tag,
我只是这个子类,我把我所有的粉碎标签,

435
00:20:00,366 --> 00:20:03,033
smash core data stuff into this subclass, so
粉碎核心数据到这个子类

436
00:20:03,102 --> 00:20:06,537
that the super class remains completely generic,
超类是完全通用的,

437
00:20:06,606 --> 00:20:09,306
I just had to make my super class a little
我不得不让我的超类

438
00:20:09,375 --> 00:20:10,942
more subclassible,
更subclassible,

439
00:20:11,910 --> 00:20:13,043
Now, as with any MVC,
现在,对于任何MVC,

440
00:20:13,112 --> 00:20:15,879
we want to think about the model of this SmashTable,
我们要思考这个SmashTable的模型,

441
00:20:15,948 --> 00:20:19,182
SmashTweetTableViewController, of course it's going to
SmashTweetTableViewController,当然会

442
00:20:19,251 --> 00:20:21,251
inherit the model of its super class,
继承超类的模型,

443
00:20:21,320 --> 00:20:24,021
But I'm also gonna add a model here,
但我也会添加一个模型,

444
00:20:24,090 --> 00:20:26,791
which is the database to use,
数据库的使用,

445
00:20:26,859 --> 00:20:31,862
And I'm gonna do it by passing in a PersistentContainer,
我要做PersistentContainer通过,

446
00:20:31,931 --> 00:20:35,766
Now normally we probably want this to be the app delegate
现在通常我们可能想要这个应用程序委托

447
00:20:35,834 --> 00:20:39,270
view, the app delegate persistence container,
看来,应用委托持久性容器,

448
00:20:39,339 --> 00:20:41,905
But I wanna allow people who are using my MVC,
但是我想允许人们使用MVC,

449
00:20:41,974 --> 00:20:43,540
to use any database they want,
他们想要使用任何数据库,

450
00:20:43,609 --> 00:20:45,876
I don't wanna force them to use that app delegate one,
我不想强迫他们使用这个应用程序委托,

451
00:20:45,945 --> 00:20:49,613
Having said that, I am gonna have the default value of
已经说过,我要的默认值

452
00:20:49,682 --> 00:20:51,649
this, go ahead and be that,
继续,,,

453
00:20:51,718 --> 00:20:57,254
So I'm gonna say (UIApplication,shared,delegate
所以我想说(UIApplication、分享委托

454
00:20:57,322 --> 00:21:01,859
as?, AppDelegate)?,persistentConta-
的吗?

455
00:21:01,928 --> 00:21:03,094
iner,
内心的,

456
00:21:03,162 --> 00:21:05,095
That's just the default value but
这是默认值

457
00:21:05,164 --> 00:21:06,897
this is a non-private var, so
这是一个私人var

458
00:21:06,966 --> 00:21:10,334
I'm using this ViewController could set the container and
我用这个ViewController可以设置容器和

459
00:21:10,403 --> 00:21:13,604
cause it to show things in a certain database,
因为它显示事情在某些数据库,

460
00:21:13,672 --> 00:21:16,673
That is essentially my model, my model is this database,
这本质上是我的模型,这是我的模型数据库,

461
00:21:16,742 --> 00:21:18,975
All this class does though is write to the database,
所有这门课虽然是写数据库,

462
00:21:19,044 --> 00:21:21,912
it's just updating the database,
只是更新数据库,

463
00:21:21,980 --> 00:21:25,716
All its UI it inherits from the super class which is non
所有的UI非从超类继承

464
00:21:25,785 --> 00:21:27,685
database oriented,
面向数据库的,

465
00:21:27,753 --> 00:21:29,987
So how do we update this database?
那么,我们如何更新该数据库?

466
00:21:30,055 --> 00:21:30,988
What do we need to do?
我们需要做什么?

467
00:21:31,057 --> 00:21:34,325
Well, one thing is, I don't really wanna update this thing
嗯,有一件事是,我不太想更新这个东西

468
00:21:34,394 --> 00:21:35,959
on the main queue, because,
在主队列,因为,

469
00:21:36,028 --> 00:21:39,396
I don't know if my super class might fetch a thousand tweets,
我不知道如果我的超类可能会卖一千条,

470
00:21:39,465 --> 00:21:41,865
And do I really wanna be blocking the main queue while
,我真的想要阻止主队列

471
00:21:41,934 --> 00:21:44,034
I go write a thousand tweets into my database?
我写了一千条微博进入数据库?

472
00:21:44,103 --> 00:21:48,506
No way, so I'm gonna take my container right here, and
没有办法,所以我要把我的容器,和

473
00:21:48,574 --> 00:21:52,943
I'm going to ask it to perform something on a background
我要问它执行一些背景

474
00:21:53,012 --> 00:21:54,278
thread,
线程,

475
00:21:54,347 --> 00:21:57,281
A background queue, and you can see, here's the argument,
背景队列,你可以看到,这里的论点,

476
00:21:57,350 --> 00:21:59,383
it's a closure and it takes one argument,
一个闭包,它接受一个参数,即

477
00:21:59,452 --> 00:22:01,285
I double-clicked on it there,
我双击后,

478
00:22:01,354 --> 00:22:03,987
I'm gonna use trailing closure syntax even,
我要使用后关闭的语法,

479
00:22:04,056 --> 00:22:05,356
So this one argument right here,
所以这里的一个参数,

480
00:22:05,424 --> 00:22:09,994
This is the manage object context for that other queue,
这是其他队列的管理对象上下文,

481
00:22:10,062 --> 00:22:14,331
the one that I'm allowed to use inside here,
我允许使用里面的,

482
00:22:14,400 --> 00:22:16,066
In order to update my database,
为了更新我的数据库,

483
00:22:16,134 --> 00:22:18,802
So I'm just gonna use that context and put these tweets,
所以我要用这个上下文和把这些推文,

484
00:22:18,871 --> 00:22:20,704
these new tweets that I got right here,
这些新的推文,我在这里,

485
00:22:20,773 --> 00:22:22,940
I'm gonna put them in the database one by one,
我要把它们放在数据库一个接一个地

486
00:22:23,008 --> 00:22:25,509
I'm just gonna say for
我只是想说

487
00:22:25,578 --> 00:22:31,048
twitterInfo in this tweets and then add tweet,
twitterInfo在这个tweet,然后加入推特,

488
00:22:32,351 --> 00:22:34,618
So, how do I do this piece of it,
所以,我怎么做这一块,

489
00:22:34,686 --> 00:22:36,319
How do I add a tweet?
我如何添加一个推特?

490
00:22:36,388 --> 00:22:39,256
And by tweet there, I mean the tweet in our data model,
的推特,推特,我的意思是我们的数据模型,

491
00:22:39,325 --> 00:22:40,523
That's what I wanna do,
这就是我想做的,

492
00:22:40,592 --> 00:22:44,828
Add a tweet in our data model that matches this Twitter info
添加一个tweet匹配这个Twitter信息在我们的数据模型

493
00:22:44,897 --> 00:22:45,729
that I got,
我得到了,

494
00:22:45,798 --> 00:22:48,732
All right, so we're gonna put the method in tweet in
好吧,所以我们要把推特的方法

495
00:22:48,801 --> 00:22:51,601
our subclass of tweet that we created right here,
我们的推特的子类创建,

496
00:22:51,670 --> 00:22:53,170
that's currently empty,
这是目前空,

497
00:22:53,239 --> 00:22:56,306
We're gonna put a static method in there to either go
我们要去把一个静态方法

498
00:22:56,375 --> 00:22:59,409
out and find a tweet that matches that twitter info or
并找到一个匹配,twitter的微博信息

499
00:22:59,478 --> 00:23:02,279
to create one if there's not one there,
创建一个如果没有一个,

500
00:23:02,347 --> 00:23:04,581
So that way they'll keep being unique, because if we get
所以这样他们会保持独特,因为如果我们得到的

501
00:23:04,650 --> 00:23:06,984
the same tweet we'll find it and just return the one that's
相同的微博我们会发现它的返回

502
00:23:07,053 --> 00:23:08,652
already there versus creating a new one,
已有与创建一个新的,

503
00:23:08,721 --> 00:23:11,755
So I'm gonna call this thing,
所以我要叫这个东西,

504
00:23:11,824 --> 00:23:15,693
it's gonna be static or if its a class,
它会是静态的或者它的一个类,

505
00:23:15,761 --> 00:23:21,065
we can say class func findOrCreatTweet, matching,
我们可以说类func findOrCreatTweet匹配,

506
00:23:21,133 --> 00:23:26,937
twitterInfo and that's going to be a Twitter,tweet,
twitterInfo是推特,推特,

507
00:23:27,006 --> 00:23:28,906
That's the info that's gonna be passed into it,
这是会传递给它的信息,

508
00:23:28,974 --> 00:23:33,577
And I need to know what context to go look in, so
我需要知道上下文去看看,

509
00:23:33,645 --> 00:23:39,783
I'm gonna say, in context, NSMan, I need some more space,
我想说,在上下文中,NSMan,我需要更多的空间,

510
00:23:39,852 --> 00:23:44,120
MSManagedObjectContext, right there,
MSManagedObjectContext,,

511
00:23:44,189 --> 00:23:46,724
And it's just going to return a tweet,
要返回一个微博,

512
00:23:49,428 --> 00:23:52,496
So this static method, class method is just going to go and
所以这个静态方法,类方法就是去

513
00:23:52,564 --> 00:23:54,798
look in the database and find this thing and
请在数据库中找到这个东西

514
00:23:54,867 --> 00:23:57,634
if it can find it, then it'll just create a new one,
如果能找到它,那么它会创建一个新的,

515
00:23:57,703 --> 00:24:01,104
So, we have to import Twitter, (let's get rid of this), and
所以,我们不得不进口Twitter,(让我们摆脱这个),

516
00:24:01,173 --> 00:24:03,507
so how are we going to do this?
所以我们要怎么做呢?

517
00:24:03,576 --> 00:24:04,574
Well this method,
这个方法,

518
00:24:04,643 --> 00:24:09,313
pretty straight forward based on all you know in Core Data,
很直接的核心数据,基于你所知道的

519
00:24:09,382 --> 00:24:12,449
First, I'm going to create a fetch request to go find
首先,我要创建一个获取请求去寻找

520
00:24:12,518 --> 00:24:13,083
this tweet,
这个微博,

521
00:24:14,720 --> 00:24:19,723
Le's do that tha's easy how about let request equal and
乐的,那如何让要求平等,很简单

522
00:24:19,792 --> 00:24:21,891
remember I have to statically type this actually so
记得我必须静态类型确实如此

523
00:24:21,960 --> 00:24:22,893
this is going to be an NS,
这将是一个NS,

524
00:24:25,497 --> 00:24:27,331
Fetch request,
获取请求,

525
00:24:27,400 --> 00:24:28,932
The fetch is what?
fetch是什么?

526
00:24:29,001 --> 00:24:30,767
Tweets,
微博,

527
00:24:30,836 --> 00:24:33,870
So I'm gonna use this nice Tweet,fetchRequest
所以我要用这个漂亮的Tweet,fetchRequest

528
00:24:33,939 --> 00:24:34,938
method to get one,
方法一,

529
00:24:35,007 --> 00:24:36,540
So that got me a fetch request,
所以让我获取请求,

530
00:24:36,608 --> 00:24:38,142
A fetch request that's on tweets,
获取请求的微博,

531
00:24:38,211 --> 00:24:39,943
That's what I have there and
这就是我在那里

532
00:24:40,012 --> 00:24:42,046
then I have to have a predicate for this,
然后我必须有一个谓语,

533
00:24:42,114 --> 00:24:45,482
So I'm gonna say the request predicate this is the thing
所以我想说请求谓词的事情

534
00:24:45,550 --> 00:24:49,520
that gonna say which tweets do you want in the database?
会说你要哪tweet的数据库?

535
00:24:49,589 --> 00:24:53,624
So predicate here, and which tweets do we want?
这里谓词,我们想要推?

536
00:24:53,692 --> 00:24:56,994
Well, we want a tweet where the unique key,
我们想要一个唯一键推,

537
00:24:57,063 --> 00:25:00,464
remember the unique key is in our data model,
记得独特的关键是在我们的数据模型中,

538
00:25:00,532 --> 00:25:02,132
I'll be going back to this data model often,
我将回到这个数据模型通常,

539
00:25:02,200 --> 00:25:04,601
But see here's that unique key right there,
但是看到这唯一键,

540
00:25:04,670 --> 00:25:08,338
We wanna know when that unique key matches what
我们想知道什么时候那独特的关键比赛

541
00:25:08,407 --> 00:25:09,373
the person passed in here,
通过在这里的人,

542
00:25:09,442 --> 00:25:10,774
The twitter info of what they passed in,
twitter信息的传入,

543
00:25:10,843 --> 00:25:17,113
So that's %@", and that's twitterInfo,identifier,
% @”,twitterInfo,标识符,

544
00:25:17,182 --> 00:25:20,650
So it turns out identifier
结果标识符

545
00:25:20,719 --> 00:25:22,720
that in our twitter info dot tweet,
,在我们点推特,推特信息

546
00:25:22,788 --> 00:25:25,356
That's the thing that you need for all time for a tweet,
这是你需要的东西时间一条微博,

547
00:25:26,725 --> 00:25:27,658
It's always the same for
它总是一样的

548
00:25:27,726 --> 00:25:29,460
the tweet even if you download it multiple times,
的推特即使你多次下载它,

549
00:25:29,528 --> 00:25:30,961
it's always the same,
它总是相同的,

550
00:25:31,030 --> 00:25:33,397
Now what about our sort predicate here, or
现在我们的谓词,或

551
00:25:33,466 --> 00:25:35,499
our sort descriptors rather?
我们的描述符,而?

552
00:25:35,568 --> 00:25:37,434
We actually don't need any sort descriptors
我们不需要任何类型描述符

553
00:25:37,503 --> 00:25:41,704
because this better match exactly one or zero,
因为这更好的完全匹配一个或零,

554
00:25:41,773 --> 00:25:45,542
So you don't need to put zero things or one thing in order,
所以你不需要把零或一件事,

555
00:25:45,611 --> 00:25:46,810
So you don't need a sort descriptor and
所以你不需要一个描述符和排序

556
00:25:46,879 --> 00:25:48,812
if you don't specify a sort descriptor you'll get them
如果你不指定一个类描述符你会得到它们

557
00:25:48,880 --> 00:25:49,813
back in random order,
在随机顺序,

558
00:25:49,882 --> 00:25:52,550
But again, we don't care what that is because it
但是,我们不在乎,是因为它

559
00:25:52,618 --> 00:25:54,552
better be zero or one or we've got problems,
更好的是零或一个或我们有问题,

560
00:25:55,521 --> 00:25:57,754
So how do I fetch this thing?
所以我拿这个东西怎么样?

561
00:25:57,823 --> 00:26:00,657
Very easy, I'm just gonna say let the matches in
很简单,我只是想说让比赛

562
00:26:00,726 --> 00:26:07,163
the database equal context,fetch(request),
数据库等背景下,获取(请求),

563
00:26:07,232 --> 00:26:11,034
Now the only thing about this is it throws,
现在唯一是它抛出,

564
00:26:11,103 --> 00:26:13,470
Cuz it might not be able to access the database,
因为它可能无法访问数据库,

565
00:26:13,538 --> 00:26:14,838
It could be all kinds of problems, whatever,
它可以是各种各样的问题,无论如何,

566
00:26:14,906 --> 00:26:18,475
So I'm gonna put this in a do try, a do catch here,
所以我要把这个在做尝试,做抓,

567
00:26:18,544 --> 00:26:24,348
So we'll do do and put try here,
所以我们会做的,在这里,

568
00:26:24,416 --> 00:26:27,350
And we'll put catch, (I'll talk about what we're gonna do
我们会把抓,(我将谈谈我们要做的

569
00:26:27,419 --> 00:26:29,286
when we catch an error there),
当我们发现一个错误),

570
00:26:29,354 --> 00:26:30,854
All right, so we got the matches,
好吧,我们有比赛,

571
00:26:30,923 --> 00:26:34,458
So these matches what's the type of this match,
这些比赛是什么类型的这场比赛,

572
00:26:34,526 --> 00:26:36,060
We got an error here, some error,
我们这里有一个错误,有些错误,

573
00:26:39,565 --> 00:26:40,030
Context,
背景下,

574
00:26:40,099 --> 00:26:41,064
Sorry,
对不起,

575
00:26:41,132 --> 00:26:46,269
NSManageObjectContext,
NSManageObjectContext,

576
00:26:46,338 --> 00:26:48,872
So what is the type of this matches right here?
所以这个匹配的类型是什么?

577
00:26:48,941 --> 00:26:49,840
Anyone wanna guess?
谁想猜一猜吗?

578
00:26:53,044 --> 00:26:56,479
Let's look, it's array of tweets,
让我们看,它是一系列微博,

579
00:26:56,548 --> 00:26:58,615
Of course I dispatched,
我当然派遣,

580
00:26:58,684 --> 00:27:00,584
I get it back an array of Tweet,
我把它弄回来一个Tweet数组,

581
00:27:00,652 --> 00:27:01,552
Excellent,
杰出、

582
00:27:01,621 --> 00:27:05,989
And it should be that the matches count
它应该是匹配数

583
00:27:06,058 --> 00:27:09,326
if it's greater that zero, then I found my tweet,
如果是更大的,零,然后我发现我的微博,

584
00:27:09,395 --> 00:27:10,494
In fact I can just return it,
事实上,我可以返回它,

585
00:27:10,563 --> 00:27:13,129
Return matches(0),
返回匹配(0),

586
00:27:13,198 --> 00:27:15,599
So I found that unique tweet,
所以我发现独特的微博,

587
00:27:15,667 --> 00:27:18,335
I'm actually gonna put an assert here though
我要把一个断言

588
00:27:18,404 --> 00:27:21,972
that if the matches,count is greater than one,
,如果匹配,数大于1,

589
00:27:22,041 --> 00:27:26,910
then some kind of database inconsistency,
然后某种数据库不一致,

590
00:27:26,979 --> 00:27:31,581
because somehow in that unique field
因为在这种独特的领域

591
00:27:31,650 --> 00:27:33,950
there's more than one of them in there so that will be bad,
有不止一个人这样会坏,

592
00:27:34,019 --> 00:27:38,222
Maybe I'll put the name of the method in here tweet dot
也许我会把方法的名称在这里推点

593
00:27:40,092 --> 00:27:44,094
that database inconsistency or something like that so,
数据库不一致或类似的东西,所以,

594
00:27:44,163 --> 00:27:44,928
I'm putting a little assert,
我把一个断言,

595
00:27:44,997 --> 00:27:47,197
Now that should never happen if I've written my code
现在,如果我写我的代码不应该发生

596
00:27:47,266 --> 00:27:49,366
properly, it should never be possible for
正确,应该不可能

597
00:27:49,435 --> 00:27:50,333
two tweets to get in there,
两个微博,

598
00:27:50,402 --> 00:27:52,202
There would have to be a bug somewhere else in my code,
其他地方会有一个错误在我的代码中,

599
00:27:52,271 --> 00:27:53,336
that's why I'm asserting here,
这就是为什么我在这里断言,

600
00:27:53,405 --> 00:27:57,374
cuz I want it to crash if that happens so that I notice it,
因为我想让它崩溃如果发生这种情况,我注意到它,

601
00:27:57,443 --> 00:27:59,977
Things aren't being duplicated without my knowledge,
事情并不在我不知情的情况下被复制,

602
00:28:01,213 --> 00:28:03,246
Now what about this catch right here?
现在这里赶呢?

603
00:28:03,315 --> 00:28:07,484
What if we tried to do this fetch to get those tweets and
如果我们试图去取回这些tweet和

604
00:28:07,552 --> 00:28:08,385
it fails?
失败了吗?

605
00:28:08,453 --> 00:28:10,353
Some problem with the database or something,
一些问题与数据库什么的,

606
00:28:10,422 --> 00:28:12,088
What should we do in here?
在这里我们应该做什么?

607
00:28:12,157 --> 00:28:17,093
Well, we could fatal error and crash,
我们可以致命错误和崩溃,

608
00:28:17,162 --> 00:28:18,495
That's what save context does,
什么拯救环境,

609
00:28:18,564 --> 00:28:21,397
by the way, in the App Delegate, it just crash,
顺便说一下,在应用程序委托,它只是崩溃,

610
00:28:21,466 --> 00:28:23,934
We could look at the error and try to figure out what it is,
我们可以看看错误并试图找出它是什么,

611
00:28:24,003 --> 00:28:24,968
things like that,
类似这样的事情,

612
00:28:25,036 --> 00:28:27,871
But you know, I don't actually know what the person who's
但你知道,我其实不知道的人

613
00:28:27,939 --> 00:28:31,108
calling this find your create tweet wants me to do
调用这个找到你创建微博要我做

614
00:28:31,177 --> 00:28:32,910
if there's a database error,
如果有一个数据库错误,

615
00:28:32,978 --> 00:28:34,577
I'm not sure, do they want me to ignore it?
我不确定,他们想让我忽略它吗?

616
00:28:34,646 --> 00:28:37,013
Do they want me to crash?
他们想让我崩溃吗?

617
00:28:37,082 --> 00:28:38,481
Do they want me to try again or something?
他们想让我再试一次吗?

618
00:28:38,550 --> 00:28:39,515
What do they want?
他们想要什么?

619
00:28:39,584 --> 00:28:43,620
So when you don't really know what your caller wants to do,
所以,当你不知道对方想要做什么,

620
00:28:43,689 --> 00:28:49,025
why not just rethrow the error,
为什么不重新抛出的错误,

621
00:28:49,094 --> 00:28:52,261
When you rethrow, that means this method throws,
当你重新抛出,这意味着该方法抛出,

622
00:28:52,330 --> 00:28:57,333
Everyone understand what I did there?
每个人都明白我在做什么吗?

623
00:28:57,402 --> 00:28:59,736
I mean this method findOrCreateTweet throw,
我的意思是这个方法findOrCreateTweet扔,

624
00:28:59,804 --> 00:29:03,406
And the only where it throws is a rethrows if this
唯一的,它将是一个重新抛出如果这

625
00:29:03,475 --> 00:29:06,476
generates an error,
生成一个错误,

626
00:29:06,544 --> 00:29:09,446
So when we call this findOrCreateTweet back in our
所以当我们称之为findOrCreateTweet回到我们

627
00:29:09,515 --> 00:29:12,049
other class where we have to be careful cuz it throws now,
其他类,我们必须要小心因为现在抛出,

628
00:29:12,117 --> 00:29:12,816
So I like to use try,
所以我喜欢用试试,

629
00:29:15,521 --> 00:29:16,653
But if we get down here,
但是如果我们得到下面,

630
00:29:16,721 --> 00:29:20,323
then we made it passed here without finding a match, so
然后我们通过这里没有找到一个匹配,

631
00:29:20,392 --> 00:29:22,225
here's what we need to create the tweet,
这就是我们需要创建微博,

632
00:29:22,294 --> 00:29:24,594
So I'm gonna say let tweet equal, and
所以我想说让tweet平等,

633
00:29:24,663 --> 00:29:25,862
how do we create a tweet?
我们如何创建一个推特?

634
00:29:25,930 --> 00:29:28,365
We just say TweetContext context,
我们只是说TweetContext上下文,

635
00:29:28,434 --> 00:29:31,935
So that creates a tweet in the database,
数据库中创建了一个微博,

636
00:29:32,003 --> 00:29:34,737
Now I can just set the tweet fields by setting the vars,
现在我可以设置微博领域中通过设置var,

637
00:29:34,806 --> 00:29:37,741
like the tweets, that's actually do that unique first,
像微博一样,其实这样做独特的第一,

638
00:29:37,809 --> 00:29:39,309
that's important one,
这很重要,

639
00:29:39,377 --> 00:29:43,113
So that's TwitterInfo,identifier,
这是TwitterInfo,标识符,

640
00:29:43,182 --> 00:29:45,148
We're gonna make sure we said that, if we don't said that,
我们要确保我们说,如果我们不能说,

641
00:29:45,216 --> 00:29:47,684
then we might start getting problems here because every
然后我们可以开始因为每一个问题

642
00:29:47,752 --> 00:29:50,653
body is unique is gonna be the same zero or blank,
身体是独一无二的是相同的零个或空白,

643
00:29:50,722 --> 00:29:51,988
either or something,
之类的,

644
00:29:52,057 --> 00:29:53,690
How about the tweets text?
微博的文本呢?

645
00:29:53,759 --> 00:30:00,296
Let's set that to the twitterInfo,text,
让我们集合twitterInfo、文本

646
00:30:00,365 --> 00:30:03,533
Here's created tweet,created,
这是推创建,创建,

647
00:30:03,602 --> 00:30:09,306
That's twitterInfo,created and
twitterInfo,创建和

648
00:30:09,375 --> 00:30:14,411
then we'll return the tweet,
然后我们返回tweet,

649
00:30:14,479 --> 00:30:16,913
Now, this line over here is gonna give us an error,
现在,这条线是要给我们一个错误,

650
00:30:16,982 --> 00:30:18,414
as soon as it catches up,
就追上了,

651
00:30:18,483 --> 00:30:20,016
And this error's kinda weird one,
这个错误有点奇怪,

652
00:30:20,085 --> 00:30:23,353
It says cannot assign a value of type 'Date' to
它说不能赋值类型的“约会”

653
00:30:23,421 --> 00:30:25,388
type 'NSDate?',
类型“NSDate ?”

654
00:30:25,457 --> 00:30:27,524
And I mentioned on one of the slides from last time,
我从上次提到的幻灯片,

655
00:30:27,593 --> 00:30:31,094
that in the database, dates are NS dates,
在数据库中,日期NS日期,

656
00:30:31,163 --> 00:30:34,431
But I also mentioned that you can automatically bridge
但我也提到过,您可以自动桥

657
00:30:34,499 --> 00:30:36,032
a date to an NS date,
一个NS日期的日期,

658
00:30:36,101 --> 00:30:37,734
And you can do that with as,
你可以这样做的,

659
00:30:37,803 --> 00:30:40,002
So I can say as NSDate,
所以我可以说NSDate,

660
00:30:40,071 --> 00:30:40,937
And that will always work,
总是工作,

661
00:30:41,006 --> 00:30:44,474
This as will always work as long as this Is an NSDate,
这是永远的工作只要这是nsdata,

662
00:30:44,543 --> 00:30:47,544
then this as will always work, it always can bridge across,
那么这个总是工作,它总是可以桥接,

663
00:30:47,613 --> 00:30:50,246
So this is kind of unfortunate that you have to do this for
这是一种不幸,你必须这样做

664
00:30:50,315 --> 00:30:52,049
your dates, but you do, sorry,
你的约会,但你,对不起,

665
00:30:53,319 --> 00:30:55,452
Okay, there's one more thing in tweet, though,
好了,有一件事在推特,不过,

666
00:30:55,520 --> 00:30:57,620
What's the missing thing in tweet?
失踪的事在微博是什么?

667
00:30:57,689 --> 00:31:00,623
Tweet,tweeter,
推特,推特,

668
00:31:00,692 --> 00:31:01,925
I've got to set my tweeter here,
我要把我推特,

669
00:31:01,994 --> 00:31:04,694
I just created this tweet, I gotta set who the tweeter is,
我刚刚创建的这个微博,我要推特是谁,

670
00:31:04,763 --> 00:31:07,497
So to do the tweeter, I'm gonna go do this exact
所以推特,我要去做这个

671
00:31:07,566 --> 00:31:12,201
same method over in TwitterUser,
同样的方法在TwitterUser,

672
00:31:12,270 --> 00:31:15,572
So that I can create a Twitter user the exact same way,
这样我可以创建一个Twitter用户相同的方式,

673
00:31:15,640 --> 00:31:18,474
So we'll call it find or create Twitter user,
所以我们叫它找到或创建Twitter用户,

674
00:31:18,543 --> 00:31:20,944
I, kind of pre canned right here cuz you're not gonna
我,以前这里因为你不会罐头

675
00:31:21,013 --> 00:31:22,479
learn anything from me typing this,
学习任何东西,从我打字,

676
00:31:22,548 --> 00:31:26,583
basically this exact same thing in again,
基本上,这同一件事情,

677
00:31:26,651 --> 00:31:28,718
Gotta import twitter,
要进口推特上

678
00:31:28,787 --> 00:31:32,022
But it's exactly the same, it has the same exact logic,
但这是完全相同的,它有相同的逻辑,

679
00:31:32,090 --> 00:31:33,055
I'm doing exactly the same thing,
我在做同样的事情,

680
00:31:33,124 --> 00:31:34,758
I'm even rethrowing,
我甚至将,

681
00:31:34,826 --> 00:31:37,828
just creating the twitter user if I can't find it,
只是创建一个twitter用户如果我找不到它,

682
00:31:37,896 --> 00:31:40,997
And for a twitter user, it's handle, the person's handle,
对于twitter用户,处理,人的处理,

683
00:31:41,066 --> 00:31:43,600
@ whatever, is the unique identifier,
@,是唯一标识符,

684
00:31:46,371 --> 00:31:48,071
So now that we know how to create a Twitter user
现在我们知道如何创建一个Twitter用户

685
00:31:48,140 --> 00:31:52,141
using that I can say Tweeter equals Twitter user,
我能说推特= Twitter用户使用,

686
00:31:52,210 --> 00:31:54,477
Find or there it is, finally recognize it,
发现或,终于承认,

687
00:31:54,546 --> 00:31:57,147
Okay, find or create Twitter user, and
好的,找到或创建Twitter用户,

688
00:31:57,215 --> 00:32:00,317
we wanna use the Tweets user field, Twitter,
我们想要使用推特用户领域,推特,

689
00:32:02,187 --> 00:32:05,955
Lowercase Twitter info dot user, that's the user,
小写的Twitter信息。用户,用户,

690
00:32:06,024 --> 00:32:08,258
Then we'll do it in the same context of course,
然后我们将用同样的背景当然,

691
00:32:10,462 --> 00:32:14,364
Now this throws, so we have to try this,
现在这把,所以我们要试试这个,

692
00:32:14,433 --> 00:32:18,201
And if it can't do it, I'm just going to fail again,
如果它不能这样做,我将再次失败,

693
00:32:18,270 --> 00:32:22,505
Here maybe I want to maybe re-throw again, possibly,
这里我想也许再次抛出收到,可能

694
00:32:22,574 --> 00:32:25,308
I might even wanna crash or something, I don't know,
我甚至想崩溃或什么东西,我不知道,

695
00:32:25,376 --> 00:32:26,310
It's not clear to me,
我不清楚,

696
00:32:27,612 --> 00:32:29,913
what to do if I can't create the twitter,
要做什么如果我不能创建twitter,

697
00:32:29,982 --> 00:32:33,716
If Tweeter is something that has to be set for
如果推特是必须设置的

698
00:32:33,785 --> 00:32:36,519
a tweet to make any sense in the database, then I probably
数据库中的任何意义的tweet,然后我可能

699
00:32:36,588 --> 00:32:39,155
do wanna re-throw or do something terrible here,
想抛出收到,做一些可怕的事情

700
00:32:39,224 --> 00:32:43,426
But by just saying try, instead I'm just giving up,
而是说试一试,我就放弃,

701
00:32:43,495 --> 00:32:44,794
okay I'm just not setting the tweeter,
好吧我只是不设置来说,

702
00:32:44,863 --> 00:32:49,399
So, there could be tweets that
所以,可能会有微博

703
00:32:49,467 --> 00:32:54,704
are created with no tweeter there,
创建与没有推特,

704
00:32:54,773 --> 00:32:56,740
Twitter user, yeah,
Twitter用户,是的,

705
00:32:56,808 --> 00:33:00,977
twitter user doesn't need to be an optional there,
twitter用户不需要一个可选的,

706
00:33:01,046 --> 00:33:02,312
Sorry, I made that accidentally,
对不起,我不小心,

707
00:33:04,315 --> 00:33:06,349
So It's just going to return a twitter user,
所以它只是返回一个twitter用户,

708
00:33:06,418 --> 00:33:09,219
And the try makes it into an optional twitter user which is
试着让它变成一个可选的twitter用户

709
00:33:09,287 --> 00:33:10,587
okay because tweeter,
因为推特,

710
00:33:10,656 --> 00:33:13,422
this relationship, is an optional twitter user,
这种关系,是一个可选的twitter用户,

711
00:33:13,491 --> 00:33:16,860
It comes out of our data model,
它来自我们的数据模型,

712
00:33:19,664 --> 00:33:22,099
So, that's it, that's how we create a tweet,
所以,就是这样,这就是我们创建一个微博,

713
00:33:22,167 --> 00:33:24,734
We need to use this method right here to put
我们需要使用这个方法

714
00:33:24,803 --> 00:33:25,868
those tweets in the database,
在数据库中,

715
00:33:25,937 --> 00:33:29,572
So, let's go back to here,
因此,让我们回到这里,

716
00:33:29,641 --> 00:33:34,210
Let's go to our SmashTweetTableViewController,
让我们去SmashTweetTableViewController,

717
00:33:34,279 --> 00:33:37,147
And here, where we wanna add the tweets, we'll just say
在这里,我们想加入微博,我们就说

718
00:33:38,683 --> 00:33:43,753
Let a Tweet equal Tweet,findOrCreateTweet,
让翠特平等,findOrCreateTweet留言;

719
00:33:43,822 --> 00:33:46,722
We'll pass it, the Twitter info,
我们会通过Twitter信息,

720
00:33:46,791 --> 00:33:49,358
That's this Twitter info right here that was passed to us and
这是这里的Twitter信息,传递给我们

721
00:33:49,427 --> 00:33:50,560
these Tweets,
这些微博,

722
00:33:50,628 --> 00:33:54,798
And in context, we're gonna use our containers context,
在上下文中,我们要使用我们的容器上下文,

723
00:33:58,670 --> 00:34:00,069
Sorry, we're not using our container context,
对不起,我们不使用容器上下文,

724
00:34:00,138 --> 00:34:02,672
We're using this context right here,
我们使用这个背景,

725
00:34:02,741 --> 00:34:04,407
So we use this little context right here,
所以我们用这个小环境,

726
00:34:04,475 --> 00:34:07,444
Now of course we know this thing throws right here,
当然我们知道这事扔在这里,

727
00:34:07,513 --> 00:34:10,080
So we'll just do try question mark here,
所以我们在这里尝试问号,

728
00:34:10,148 --> 00:34:13,282
Because here I do know that when I'm updating
因为我知道当我更新

729
00:34:13,351 --> 00:34:14,884
if I can't create that tweet, I'm just gonna drop it,
如果我不能创建这个微博,我要放弃,

730
00:34:14,885 --> 00:34:16,418
the database,
数据库,

731
00:34:16,487 --> 00:34:18,588
It's not gonna hurt anything if just not collecting
它不会伤害任何东西如果不收集

732
00:34:18,656 --> 00:34:19,455
the data it needs too,
它需要的数据,

733
00:34:19,524 --> 00:34:21,891
There's really nothing I can do about it whatever
其实我能为力

734
00:34:21,959 --> 00:34:24,827
the database error is it's in there maybe I could report
数据库错误是在那里也许我可以报告

735
00:34:24,896 --> 00:34:27,464
an error to the user and say couldn't update data base but
一个错误给用户说但不能更新数据基地

736
00:34:27,532 --> 00:34:29,332
a lot of times user are like what the heck is that,
很多时候用户就像究竟是怎么一回事,

737
00:34:29,401 --> 00:34:34,971
So here dropping it is probably fine,
这里下降可能是好,

738
00:34:35,040 --> 00:34:37,674
Now notice we have a warning here, see this warning?
注意这里有一个警告,看到这个警告?

739
00:34:37,743 --> 00:34:41,744
It says let tweet equals and you never use tweet, and
让微博=和你永远不使用推特,和

740
00:34:41,813 --> 00:34:44,113
in fact I don't wanna use tweet,
事实上我不想使用微博,

741
00:34:44,182 --> 00:34:47,917
So what do you do in this case where I found and
所以你做什么工作在这种情况下,我发现

742
00:34:47,986 --> 00:34:49,552
create this tweet but I actually don't want it,
创建这个tweet但我真的不想要它,

743
00:34:49,621 --> 00:34:50,587
I don't wanna do anything,
我不想做任何事情,

744
00:34:50,656 --> 00:34:52,989
I just wanted it to get created if it wasn't there,
我只是想让它得到了如果它不在那里,

745
00:34:53,057 --> 00:34:55,257
Well here you can say, "Under bar",
这里你可以说,“在酒吧”,

746
00:34:55,326 --> 00:34:59,829
If you say _ =" something it means I'm ignoring the return
如果你说_ = "这意味着我忽略了返回的东西

747
00:34:59,897 --> 00:35:01,831
value, which is fine,
值,这是可以的,

748
00:35:01,900 --> 00:35:04,301
I don't need the return value I just want this thing created
我不需要返回值我想这事了

749
00:35:04,369 --> 00:35:06,403
in the database, doesn't have to do anything,
在数据库中,不需要做任何事情,

750
00:35:08,340 --> 00:35:10,539
Everybody following me so far here?
每个人都跟着我到目前为止吗?

751
00:35:10,608 --> 00:35:12,776
So now we have loaded up the database,
现在我们有装数据库,

752
00:35:12,845 --> 00:35:14,544
That's it, That's all of the code we need
就是这样,这就是我们需要的所有代码

753
00:35:14,613 --> 00:35:16,646
to load our database up with all these tweets,
加载数据库所有这些推文,

754
00:35:16,715 --> 00:35:20,383
Now let's go ahead and print some database statistics here
现在让我们去打印一些数据库统计数据

755
00:35:20,451 --> 00:35:22,852
just to see if this is working before we go off and
只是为了看看这是工作在我们离开之前,

756
00:35:22,921 --> 00:35:25,755
do our UI for a new MBC,
做我们的UI MBC,

757
00:35:25,824 --> 00:35:30,293
So I'm gonna say, printDatabaseStatistics and
所以我会说,printDatabaseStatistics和

758
00:35:30,362 --> 00:35:34,630
I'm gonna create a new private func here called
我要创建一个新的私人func叫

759
00:35:34,699 --> 00:35:37,734
printDatabaseStatistics,
printDatabaseStatistics,

760
00:35:37,803 --> 00:35:41,370
Copy, paste,
复制,粘贴,

761
00:35:41,439 --> 00:35:44,874
And what I want this thing to do is tell me how many tweets
我想要这个东西做告诉我多少tweet

762
00:35:44,943 --> 00:35:47,076
and how many twitter users are in the database,
和有多少twitter用户在数据库中,

763
00:35:47,145 --> 00:35:50,446
That's all I wanted to do here,
这就是我想做的,

764
00:35:50,515 --> 00:35:53,383
So if I wanna do anything in the database, if
如果我想做任何事在数据库中,如果

765
00:35:53,451 --> 00:35:56,452
I wanna look in the database I obviously need a context,
我想看数据库中我显然需要一个背景下,

766
00:35:56,521 --> 00:35:58,121
I have to have a context to
我必须有一个上下文

767
00:36:00,058 --> 00:36:01,357
look inside the database or whatever,
看在数据库或其他,

768
00:36:01,426 --> 00:36:03,192
So what context am I gonna use?
上下文我要使用什么?

769
00:36:03,261 --> 00:36:08,064
I'm gonna say, if I can let my let context equal my
我想说,如果我可以让我让上下文相同

770
00:36:08,133 --> 00:36:11,234
containers?,viewContext,
viewContext,容器?

771
00:36:11,303 --> 00:36:15,104
Now the viewContext Is the mainqueue context for
现在viewContext mainqueue上下文

772
00:36:15,173 --> 00:36:17,006
this database,
这个数据库,

773
00:36:17,075 --> 00:36:19,342
So, I'm gonna have printDatabaseStatistics,
所以,我要有printDatabaseStatistics,

774
00:36:19,411 --> 00:36:21,811
It's not inside this closure, so
这不是在这个闭包,

775
00:36:21,880 --> 00:36:23,613
it's not gonna use this context,
它不会使用这样的背景下,

776
00:36:23,682 --> 00:36:25,448
We'll have it use the main viewContext,
我们会使用主要viewContext,

777
00:36:25,517 --> 00:36:28,752
This is pretty much, unless you had it perform background
这是相当多的,除非你把它做背景

778
00:36:28,820 --> 00:36:31,754
tasks, this is pretty much the only context you have, so
任务,这几乎是唯一的上下文,所以

779
00:36:31,823 --> 00:36:33,623
we'll have it do on the main context,
我们要做的主要背景,

780
00:36:33,692 --> 00:36:36,692
So how am I gonna find out how many tweets there are?
那么我要如何找到有多少条?

781
00:36:36,761 --> 00:36:39,629
Okay, I'm gonna create a request and do a fetch,
好的,我要创建一个请求并取回,

782
00:36:39,698 --> 00:36:41,464
So NSFetchRequest,
所以NSFetchRequest,

783
00:36:42,734 --> 00:36:44,934
And this one is a request for tweets,
这个是一个tweet请求

784
00:36:45,003 --> 00:36:47,571
Equals Tweet,fetchRequest,
= Tweet,fetchRequest,

785
00:36:47,639 --> 00:36:50,206
So now I got this request, the fetch request
现在我有这个请求,获取请求

786
00:36:50,275 --> 00:36:54,844
I need no predicate here because I want all the tweets,
我需要没有谓词,因为我希望所有的微博,

787
00:36:54,913 --> 00:36:58,214
If you have no predicate that means give me them all,
如果你没有谓语就意味着给我,

788
00:36:58,282 --> 00:37:02,151
So that's what I want, and so now I'm just going to
这就是我想要的,所以现在我要

789
00:37:02,220 --> 00:37:07,390
say here if I can let the tweetCount equal
说如果我能让tweetCount相等

790
00:37:07,458 --> 00:37:12,629
trying to access the context to fetch this request,
试图访问上下文获取这个请求,

791
00:37:12,697 --> 00:37:14,831
Which it may or not be able to do,
它是否可以做,

792
00:37:14,899 --> 00:37:19,302
But if it can then you understand what I did there?
但是如果你能理解我所做的吗?

793
00:37:20,371 --> 00:37:22,138
Then I'm going to get the count,
然后我将得到计数,

794
00:37:24,775 --> 00:37:26,943
What's the type of that expression?
这个表达式的类型是什么?

795
00:37:28,713 --> 00:37:31,381
Optional array of tweets,
可选的微博,

796
00:37:31,449 --> 00:37:34,384
Because this returns an array of tweets if it
因为这个tweet如果它返回一个数组

797
00:37:34,453 --> 00:37:37,386
doesn't throw and this turns into an optional,
不把这变成一个可选的,

798
00:37:37,455 --> 00:37:39,589
So this is an optional array of tweets,
这是一个可选的微博,

799
00:37:39,658 --> 00:37:41,857
Here I'm optional chaining,
这里我可选的链接,

800
00:37:41,926 --> 00:37:45,194
So if that's not new then I get to continue and
如果这不是新的然后我得到继续

801
00:37:45,263 --> 00:37:46,328
get the count,
数,

802
00:37:46,397 --> 00:37:49,565
This is just array's count, this is a method count in
这仅仅是数组的计算,这是一个计数的方法

803
00:37:49,634 --> 00:37:52,535
array a var for the count in array,
在数组,数组的var计算

804
00:37:52,604 --> 00:37:58,408
Now I've got the tweetCount, now I'm just gonna say print,
现在我有tweetCount,现在我只是想说打印,

805
00:37:58,476 --> 00:38:02,979
tweetCount, tweets, and that's it,
tweetCount、微博,就是这样,

806
00:38:03,048 --> 00:38:06,383
I fetch them all,
我取回,

807
00:38:06,451 --> 00:38:10,353
I just fetched every tweet in the entire database,
我只是获取每条tweet在整个数据库,

808
00:38:10,422 --> 00:38:12,188
just to find out how many there were,
为了找出有多少,

809
00:38:12,257 --> 00:38:14,323
What if there's a 100,000 Tweets in there?
如果有100000微博呢?

810
00:38:14,392 --> 00:38:16,792
I'm really gonna fetch and that, of course we know that
我真的要卖,当然我们知道

811
00:38:16,861 --> 00:38:19,328
it's only gonna fault sum of min until I ask for the data,
它只会错之和最小,直到我问的数据,

812
00:38:19,397 --> 00:38:21,163
So it's not that bad but
所以它没那么糟糕,但

813
00:38:21,232 --> 00:38:23,599
there's a better way to do this,
有一个更好的方法来做到这一点,

814
00:38:23,668 --> 00:38:25,801
By the way here's another, before I show that,
顺便说一下这是另一个,在我表明,

815
00:38:25,870 --> 00:38:28,270
See this request I made this separate variable, right here,
看到这个请求我做这个独立的变量,在这里,

816
00:38:28,339 --> 00:38:30,006
That's not actually necessary,
实际上这并不是必要的,

817
00:38:30,075 --> 00:38:32,475
I can just take this request right here and
我可以把这个请求

818
00:38:32,543 --> 00:38:33,976
put it right in,
正确的,

819
00:38:34,045 --> 00:38:35,044
To here,
到这里,

820
00:38:35,113 --> 00:38:35,978
Watch this,
看这个,

821
00:38:36,047 --> 00:38:40,283
Cut, paste, and get rid of that,
剪切、粘贴和摆脱,

822
00:38:40,352 --> 00:38:43,285
That's because the fetch method takes
这是因为fetch方法

823
00:38:43,354 --> 00:38:45,354
any kind of fetch request,
任何一种获取请求,

824
00:38:45,423 --> 00:38:49,492
It takes anything whose type is a fetchRequest result
需要任何的类型是fetchRequest结果

825
00:38:49,561 --> 00:38:51,294
basically, which is a protocol,
基本上,这是一个协议,

826
00:38:51,363 --> 00:38:54,129
And so I didn't have to create that other variable,
所以我不需要创建其他变量,

827
00:38:54,198 --> 00:38:56,232
And notice I don't have to statically type this because
注意这个,因为我不需要静态类型

828
00:38:56,301 --> 00:38:58,501
this would take anything that returns a fetchRequest,
这将返回一个fetchRequest,

829
00:38:58,569 --> 00:38:59,602
It'd return something,
它会返回一些东西,

830
00:38:59,671 --> 00:39:02,071
So anyway, so
所以无论如何,

831
00:39:02,140 --> 00:39:04,274
what's the better way to do counting right here?
有什么更好的方法来计算在这里吗?

832
00:39:04,343 --> 00:39:07,276
Is I'm gonna say if let tweeterCount, so
我想说如果让tweeterCount,所以呢

833
00:39:07,345 --> 00:39:10,880
I'll count the tweeters in this better way, equals try
我会计算高音在这个更好的方法,等于试一试

834
00:39:12,083 --> 00:39:16,719
to get the context,count for:
上下文,计数:

835
00:39:16,787 --> 00:39:22,992
TwitterUsers,fetchRequest, okay, all twitter users,
TwitterUsers fetchRequest,好吧,所有的twitter用户,

836
00:39:24,462 --> 00:39:27,263
Then I can print the twitterCount,
然后我可以打印twitterCount,

837
00:39:30,935 --> 00:39:36,605
Twitter users,
Twitter用户,

838
00:39:36,674 --> 00:39:40,143
So this method count is very much like fetch but
这方法很像卖但计数

839
00:39:40,211 --> 00:39:43,913
it doesn't is still kinda evaluating this fetch request,
它不仍有点评估这个获取请求,

840
00:39:43,982 --> 00:39:44,913
it's getting the same things,
同样的事情,

841
00:39:44,982 --> 00:39:46,882
In this case we're counting users, but
在这种情况下,我们计算的用户,但是

842
00:39:46,951 --> 00:39:48,851
it's really just asking the data base,
它只是要求数据基础,

843
00:39:48,920 --> 00:39:54,256
If I were to fetch this, how many would you give me?
如果我拿这个,你会给我多少?

844
00:39:54,325 --> 00:39:56,158
So it's all done on the database side,
这是所有在数据库端完成,

845
00:39:56,227 --> 00:39:57,827
nothing actually has to get fetched,
没有什么实际上获取,

846
00:39:59,030 --> 00:40:00,563
So it's just another method count,
这只是另一种方法计算,

847
00:40:00,632 --> 00:40:02,899
But it does throw, as well, in the same was as Fetch does,
但它扔,相同的是获取,

848
00:40:02,968 --> 00:40:04,366
So we still have to do try,
所以我们仍然要做尝试,

849
00:40:04,435 --> 00:40:08,138
So this whole expression right here, isn't option int,
所以整个表达式,不是选择int,

850
00:40:09,641 --> 00:40:12,609
So I'm unwrapping it with if let, and printing it out,
如果让我打开它,打印出来,

851
00:40:14,545 --> 00:40:15,111
Got all that?
得到了所有吗?

852
00:40:16,781 --> 00:40:19,282
Let's cross our fingers here that this
这让我们交叉手指

853
00:40:19,351 --> 00:40:21,751
all works that we've got all this database learning,
所有作品,我们有这个数据库学习,

854
00:40:21,820 --> 00:40:27,122
And we gonna print our database
我们会打印数据库

855
00:40:27,191 --> 00:40:34,197
statistics and it all gonna work,
统计所有要工作,

856
00:40:34,265 --> 00:40:40,002
Here we go and this is just some junk from IOS there so
好了,这只是一些垃圾从IOS

857
00:40:40,071 --> 00:40:41,871
we'll ignore that,
我们会忽略,

858
00:40:41,939 --> 00:40:43,739
Right here let's search for some,
让我们找一些,

859
00:40:43,808 --> 00:40:46,642
Let's search for, how about hash tag stan,
让我们寻找,散列标签斯坦,

860
00:40:46,711 --> 00:40:49,178
well let's do hash tag stan, yeah, that's a good one,
好让我们做散列标签斯坦,是的,这是一个很好的一个,

861
00:40:49,247 --> 00:40:52,882
All right, it wants to use my Twitter account,
好吧,它希望用我的Twitter帐户,

862
00:40:52,950 --> 00:40:55,851
Sure, here it is, and,
当然,在这里,,

863
00:40:55,920 --> 00:40:59,755
Uh-oh, look on the console there,
哦,看在控制台上,

864
00:40:59,824 --> 00:41:02,992
Zero tweets, zero Twitter users,
零,零推特用户,

865
00:41:04,829 --> 00:41:07,296
Maybe let's pull some more,
也许我们拉一些,

866
00:41:07,365 --> 00:41:10,833
No, it's still zero tweets, zero Twitter user,
不,它仍然是零tweet,零Twitter用户,

867
00:41:10,901 --> 00:41:12,402
Well it's not working,
这不是工作,

868
00:41:13,571 --> 00:41:16,738
Anyone see anything in this code for
任何人看到这个代码的任何东西

869
00:41:16,807 --> 00:41:18,208
why this is not working,?
为什么这是不工作,?

870
00:41:20,778 --> 00:41:24,480
Yeah, we're doing a good job of loading up that database,
是的,我们正在做一份好工作的加载数据库,

871
00:41:24,548 --> 00:41:25,982
but we never save it,
但是我们从来没有保存它,

872
00:41:27,218 --> 00:41:29,886
So all that is just waste of time,
所以这只是浪费时间,

873
00:41:29,954 --> 00:41:34,356
we need to say try, context, save,
我们需要说、上下文、保存

874
00:41:34,425 --> 00:41:35,924
Now again I'm ignoring the error here,
现在我在这里忽略错误,

875
00:41:35,993 --> 00:41:38,494
In a demo a lot of the time I use try, question mark because
在一个演示我尝试使用很多时候,问号,因为

876
00:41:38,563 --> 00:41:40,229
I just don't have time to do the due catch and
我只是没有时间去捕捉和

877
00:41:40,297 --> 00:41:41,531
handle all the errors,
处理所有的错误,

878
00:41:41,600 --> 00:41:42,632
That's something you should
这是你应该的

879
00:41:42,700 --> 00:41:44,033
be looking at the option of doing,
看着做的选择,

880
00:41:44,102 --> 00:41:45,168
So here I'm just gonna save and
这里我要保存并

881
00:41:45,237 --> 00:41:47,136
ignore any errors, alright?
忽略任何错误,对吧?

882
00:41:47,205 --> 00:41:48,671
So that should fix it right?
所以,应该修理它?

883
00:41:48,740 --> 00:41:57,346
Let's go see,
让我们去看看,

884
00:41:57,414 --> 00:41:58,447
All right, here we go,
好吧,我们开始吧,

885
00:41:58,516 --> 00:42:03,218
Hash tag Stanford,
散列标签斯坦福大学,

886
00:42:03,287 --> 00:42:04,020
No,
不,

887
00:42:04,089 --> 00:42:05,421
Zero tweet,
0条,

888
00:42:05,490 --> 00:42:06,555
Zero Twitter users,
零Twitter用户,

889
00:42:06,624 --> 00:42:08,524
I put that save in there,
我把它保存在那里,

890
00:42:08,593 --> 00:42:09,324
What is going on?
什么是怎么回事?

891
00:42:09,393 --> 00:42:10,827
I had to pull again,
我不得不再次拉,

892
00:42:12,030 --> 00:42:15,697
Look, I pulled and it worked,
看,我把这工作,

893
00:42:15,766 --> 00:42:17,233
What the heck is going on?
到底是怎么回事?

894
00:42:17,302 --> 00:42:19,902
When I first loaded up it said zero tweets and
当我第一次装tweets和它说零

895
00:42:19,971 --> 00:42:21,837
then now it's saying 57th,
然后现在是说第57位,

896
00:42:21,906 --> 00:42:23,773
Something weird going on here,
奇怪的东西,

897
00:42:23,842 --> 00:42:25,174
What's happening?
发生什么事情了?

898
00:42:25,243 --> 00:42:28,877
Well, this is actually a multi threading problem,
这实际上是一个多线程问题,

899
00:42:28,946 --> 00:42:32,881
Can anyone see the multi-threading problem here?
谁能看到这里的多线程问题吗?

900
00:42:32,950 --> 00:42:34,583
No? I'm gonna put some print in,
没有?

901
00:42:34,652 --> 00:42:35,384
so you can see it,
所以你可以看到它,

902
00:42:35,453 --> 00:42:42,258
So watch this, print, starting database load,
所以看这个,打印,从数据库加载,

903
00:42:42,327 --> 00:42:45,328
And then down here, when I'm done with the save here,
然后下面,当我完成了保存在这里,

904
00:42:45,396 --> 00:42:49,566
I'm gonna just print, done loading database,
我要打印,完成加载数据库,

905
00:42:50,935 --> 00:42:56,472
And there, so
在那里,所以

906
00:42:56,541 --> 00:43:03,012
now let's run,
现在,让我们来运行,

907
00:43:03,081 --> 00:43:08,451
All right, hash tag Stanford,
好了,散列标签斯坦福大学,

908
00:43:08,519 --> 00:43:12,755
Got a crash there, database inconsistency, interesting,
有崩溃,数据库不一致,有趣,

909
00:43:12,823 --> 00:43:15,324
So this is why we put this inserts in here,
所以这就是为什么我们把这个插入在这里,

910
00:43:15,393 --> 00:43:18,193
Asserts in here, so let's see why do we think we have
断言在这里,让我们看看为什么我们认为我们有

911
00:43:18,262 --> 00:43:20,163
a data basing consistency here?
数据基于一致性呢?

912
00:43:22,334 --> 00:43:22,899
Yeah?
是吗?

913
00:43:29,006 --> 00:43:29,772
>> That's what it is,
> >这是它是什么,

914
00:43:29,840 --> 00:43:32,208
Yes, my search is backwards, there,
是的,我的搜索是向后的,,

915
00:43:32,276 --> 00:43:34,643
I'm inserting here that matches,count == 1,
我在这里插入相匹配,计算= = 1,

916
00:43:34,712 --> 00:43:37,580
So that's why that's crashing, okay,
这就是为什么崩溃,好吧,

917
00:43:37,648 --> 00:43:42,718
Good, Let's
好,让我们

918
00:43:42,787 --> 00:43:47,723
go back,
回去,

919
00:43:47,792 --> 00:43:49,993
Now let's try again, hashtag Stanford,
现在,让我们再试一次,标签斯坦福大学,

920
00:43:52,263 --> 00:43:55,030
Let's see what's going on down here,
下面让我们来看看发生了什么,

921
00:43:55,099 --> 00:43:59,568
Starting database load, it prints the statistics, and
从数据库加载,它打印统计,

922
00:43:59,637 --> 00:44:01,170
then it's done loading,
然后加载完成,

923
00:44:01,239 --> 00:44:02,671
That's bad,
这是坏的,

924
00:44:02,740 --> 00:44:04,273
You see, it's not waiting for
你看,这不是等待

925
00:44:04,342 --> 00:44:07,143
it to be done loading before it prints the statistics,
它加载完成之前打印统计,

926
00:44:08,279 --> 00:44:08,744
You see?
你看到了什么?

927
00:44:08,813 --> 00:44:10,813
Now why is that happening?
现在为什么发生?

928
00:44:10,882 --> 00:44:14,583
Because we're putting print databaseStatistics here after
因为我们将打印后databaseStatistics这里

929
00:44:14,652 --> 00:44:15,117
downloading,
下载,

930
00:44:15,186 --> 00:44:17,419
So why isn't it saying starting, done,
为什么不是说开始,完成,

931
00:44:17,488 --> 00:44:18,687
and then printing?
然后打印?

932
00:44:18,756 --> 00:44:22,391
Because this right here,
因为这里,

933
00:44:22,460 --> 00:44:27,263
happens on a different queue,
发生在一个不同的队列,

934
00:44:27,331 --> 00:44:29,098
So the way that this code goes is,
所以这段代码的方式,

935
00:44:29,167 --> 00:44:33,102
starting, this execute returns immediately,
开始,这个执行立即返回,

936
00:44:33,171 --> 00:44:34,603
Because all it does is put this
因为它所做的是把这个

937
00:44:34,672 --> 00:44:37,640
closure onto the background task queue,
关闭后台任务队列,

938
00:44:37,709 --> 00:44:38,775
Then this happens,
然后这一切发生的时候,

939
00:44:40,144 --> 00:44:43,612
Then, this closure starts running on that background
然后,这个闭包开始运行在这一背景下

940
00:44:43,681 --> 00:44:45,714
queue, loads up these things,
队列,加载了这些事情,

941
00:44:45,783 --> 00:44:46,649
And it prints,
它打印,

942
00:44:48,419 --> 00:44:49,619
Do you see what's going on there?
你看到那边发生了什么吗?

943
00:44:49,688 --> 00:44:52,221
Everyone understand the multi-threading?
每个人都理解多线程?

944
00:44:52,290 --> 00:44:55,224
So the way to make this work is to take print database
所以做这项工作的方法是采取打印数据库

945
00:44:55,293 --> 00:44:57,627
statistics, and put it inside here,
统计数据,并把它在这里,

946
00:45:01,665 --> 00:45:03,799
All right, cuz now it's not going to print the database
现在好了,因为它不会打印数据库

947
00:45:03,868 --> 00:45:05,701
statistics until it's done,
统计数据,直到它完成

948
00:45:05,770 --> 00:45:07,836
Now this has a problem though,
现在有一个难题,

949
00:45:07,905 --> 00:45:09,838
Okay, this is very bad,
好的,这是非常糟糕的,

950
00:45:09,907 --> 00:45:12,575
First of all, we're gonna have to do, I'm not sure why it's
首先,我们要做的,我不知道为什么

951
00:45:12,644 --> 00:45:14,577
not complaining here, there we go, now it is,
不抱怨,好了,现在,

952
00:45:14,645 --> 00:45:18,281
It wants to know, it wants self dot here, so
要知道,它希望self。,所以

953
00:45:18,349 --> 00:45:22,652
I'm gonna do weak self to break that memory cycle,
我要做弱自我突破,记忆周期,

954
00:45:22,720 --> 00:45:25,988
Hopefully everyone understands that now, what's going on,
希望每个人都明白,这是怎么回事,

955
00:45:26,057 --> 00:45:26,588
Okay,
好吧,

956
00:45:26,657 --> 00:45:27,656
But that's not the problem here,
但这不是问题,

957
00:45:27,725 --> 00:45:29,191
There's an even worse problem,
有一个更糟糕的问题,

958
00:45:29,260 --> 00:45:30,459
And in the interest of time,
由于时间关系,

959
00:45:30,528 --> 00:45:34,664
I'm going to put a print down in here to show you something,
我要放下一个打印在这里给你看些东西,

960
00:45:36,233 --> 00:45:39,034
If I'm gonna check to see if this code
如果我要看看这段代码

961
00:45:39,103 --> 00:45:40,302
is running on the main thread,
运行在主线程,

962
00:45:40,371 --> 00:45:41,637
So I'm gonna say IF,
所以我想说,如果

963
00:45:41,706 --> 00:45:46,342
and the way you do that is you say thread,ismainthread,
你说你这样做的方法是线程,ismainthread,

964
00:45:46,411 --> 00:45:47,743
Okay, if I'm in the main thread it'll be true,
好吧,如果我在主线程会是真的,

965
00:45:47,812 --> 00:45:51,280
So I'm gonna say on main thread,
所以我想说在主线程,

966
00:45:51,349 --> 00:45:57,920
And if it's not true, I'm gonna say off main thread,
如果这不是真的,我要从主线程说,

967
00:45:57,988 --> 00:46:01,289
So let's see if this statistics is happening
让我们看看这个数据正在发生的事情

968
00:46:01,358 --> 00:46:02,992
on the main thread or not,
在主线程,

969
00:46:03,061 --> 00:46:06,195
I think many of you know which one it's going to be,
我想很多人都知道这将是哪一个,

970
00:46:07,565 --> 00:46:09,331
By looking at the code here,
通过查看代码,

971
00:46:09,400 --> 00:46:13,135
All right, here we go again, hash tag Stanford,
好吧,又来了,散列标签斯坦福大学,

972
00:46:13,204 --> 00:46:15,304
Here we go,
我们开始吧,

973
00:46:15,372 --> 00:46:16,672
Off main thread,
主线程,

974
00:46:18,342 --> 00:46:19,842
Okay, why is it off the main thread?
好的,为什么从主线程?

975
00:46:19,911 --> 00:46:22,511
Because I called print database statistics inside
因为我叫打印数据库统计进去

976
00:46:22,580 --> 00:46:25,548
this closure, it happens on a background thread thus this
这个闭包,它发生在一个后台线程

977
00:46:25,617 --> 00:46:28,117
entire method is happening off the main thread,
整个方法正在发生的主线程,

978
00:46:28,186 --> 00:46:30,152
Now, is that a problem?
现在,这是一个问题吗?

979
00:46:30,221 --> 00:46:34,824
That's a huge problem, because what context am I using here?
这是一个巨大的问题,因为我正在使用什么背景呢?

980
00:46:34,892 --> 00:46:36,192
The mainQueue context,
mainQueue上下文,

981
00:46:37,295 --> 00:46:40,129
ViewContext is the mainQueue context,
ViewContext mainQueue上下文,

982
00:46:40,198 --> 00:46:44,333
I cannot be using the mainQueue context off the main
我不能使用mainQueue上下文主要

983
00:46:44,402 --> 00:46:45,200
thread,
线程,

984
00:46:45,269 --> 00:46:47,303
You see the problem here?
你看到这里的问题吗?

985
00:46:47,372 --> 00:46:50,572
So it worked, but could have easily crashed or
它工作,但是可以轻松或坠毁

986
00:46:50,641 --> 00:46:51,674
done something terrible,
做可怕的事情,

987
00:46:51,742 --> 00:46:53,876
So how do we fix that?
那么,我们如何解决这个问题?

988
00:46:53,945 --> 00:46:55,944
This is where we use that method I was telling
这就是我告诉我们使用方法

989
00:46:56,013 --> 00:46:58,246
you about in context called perform,
你在上下文中执行,

990
00:46:58,315 --> 00:47:04,287
I'm gonna say context perform this code on your safe queue,
点击安全队列上下文执行这段代码,

991
00:47:06,457 --> 00:47:11,059
When I say context perform and I put this code in there,
当我说上下文执行和我把这段代码,

992
00:47:11,128 --> 00:47:13,562
it says to that context, do this block but
它说,这种情况下,块,但这样做

993
00:47:13,630 --> 00:47:17,599
whatever you do, do it on the right queue for you,
无论你做什么,对你做正确的队列,

994
00:47:17,668 --> 00:47:20,068
And since this is the view context,
因为这是背景,

995
00:47:20,137 --> 00:47:26,175
it's going to be back on the main thread,
这将是回到主线程,

996
00:47:26,244 --> 00:47:29,378
watch,
手表,

997
00:47:29,447 --> 00:47:32,814
Hashtag Stanford,
标签斯坦福大学,

998
00:47:32,883 --> 00:47:34,851
Here we go back on main thread,
我们回到主线程,

999
00:47:36,353 --> 00:47:39,688
So this perform right here is something that
所以这里的执行的东西

1000
00:47:39,757 --> 00:47:41,356
a lot of people would advise,
很多人建议,

1001
00:47:41,425 --> 00:47:45,594
always use it unless you're Inside one of these where it's
总是使用它,除非你在其中一个的

1002
00:47:45,663 --> 00:47:49,298
clearly using this context in this background thing,
显然使用这个背景在这个背景,

1003
00:47:49,366 --> 00:47:50,232
Any other time,
其他时间,

1004
00:47:50,300 --> 00:47:52,401
a lot of people say always wrap your calls in this,
很多人说总是在这个包裹你的电话,

1005
00:47:52,469 --> 00:47:54,903
That way, you'll never have a problem where some things
这样,你永远不会有一个问题,一些东西

1006
00:47:54,972 --> 00:47:58,307
being executed on the wrong thread, okay, wrong que,
被错误的线程上执行,好吧,错了,

1007
00:47:59,643 --> 00:48:01,177
Understood all that?
理解这一切吗?

1008
00:48:01,245 --> 00:48:04,346
A little crash course in core data thread safety there,
有点速成课核心数据线程安全,

1009
00:48:04,415 --> 00:48:07,382
All right, so this is great,
好的,这是伟大的,

1010
00:48:07,451 --> 00:48:09,284
We've got our database loading up, so
我们有我们的数据库加载,所以

1011
00:48:09,353 --> 00:48:11,153
we've got a database full of tweets,
我们有一个数据库的微博,

1012
00:48:11,222 --> 00:48:16,191
Now, we want to add some UI to show all this data somehow,
现在,我们要添加一些UI显示所有这些数据在某种程度上,

1013
00:48:16,260 --> 00:48:18,327
So let's go back to our storyboard and take a look,
让我们回到故事板,看一看,

1014
00:48:18,396 --> 00:48:19,061
what we got here,
我们所得到的,

1015
00:48:19,130 --> 00:48:21,930
And what kinda UI we're gonna have?
有点UI我们要什么?

1016
00:48:21,999 --> 00:48:24,766
Like I said, I'm just gonna have another MVC over here
就像我说的,我要有另一个MVC

1017
00:48:24,835 --> 00:48:27,903
that I'm gonna segue to, with a little bar button item,
我要继续,小工具栏按钮,

1018
00:48:27,972 --> 00:48:30,239
So how many of you figured out how to use a bar button item
所以你们中有多少人知道如何使用工具栏按钮

1019
00:48:30,307 --> 00:48:32,374
as part of your homework assignment I think?
你的作业我认为一部分?

1020
00:48:32,443 --> 00:48:34,943
But if you didn't you're gonna see today how to do it, and
但如果你今天没你会看到怎么做,和

1021
00:48:35,012 --> 00:48:36,311
it's quite simple,
这很简单,

1022
00:48:36,380 --> 00:48:40,216
So this new MVC that I'm gonna segue to, let's go ahead and
这新的MVC,我会继续,让我们继续

1023
00:48:40,285 --> 00:48:43,385
create an MVC for it, Cocoa Touch Class,
创建一个MVC,可可触摸类,

1024
00:48:43,453 --> 00:48:45,053
It is just going to be a sub class
它就是一个次级类

1025
00:48:45,122 --> 00:48:46,588
of UITableViewController,
UITableViewController,

1026
00:48:46,657 --> 00:48:50,392
I'm gonna call it SmashTweetersTableViewControl-
我要叫它SmashTweetersTableViewControl -

1027
00:48:50,460 --> 00:48:52,360
ler, so this is showing tweeters,
l,这是显示推特,

1028
00:48:52,429 --> 00:48:54,229
Remember this table's gonna show all the tweeters who
记住这个表会显示所有的高音

1029
00:48:54,298 --> 00:49:00,402
tweeted the tweets that are in the other MVC,
在其他MVC推的推,

1030
00:49:00,471 --> 00:49:03,072
We'll put it up at the, not in the Twitter project,
我们将把它的,而不是在Twitter的项目中,

1031
00:49:03,140 --> 00:49:03,805
that's for sure,
那是肯定的,

1032
00:49:03,874 --> 00:49:05,340
Let's put it down here, okay?
让我们把它在这里,好吗?

1033
00:49:05,409 --> 00:49:07,443
I always check this list, this one here or
我总是检查这个列表,这个

1034
00:49:07,511 --> 00:49:09,611
you end up with files all in random places,
你最终得到的文件都在随机的地方,

1035
00:49:09,680 --> 00:49:12,181
You don't want that,
你不想要,

1036
00:49:12,249 --> 00:49:13,181
Here it is, Again,
在这里,再一次,

1037
00:49:13,250 --> 00:49:15,417
I'm gonna delete all this stuff,
我要删除所有这些东西,

1038
00:49:15,486 --> 00:49:16,552
See it's a tableView, so
看到这是一个视图,所以

1039
00:49:16,621 --> 00:49:19,187
it's got all this UITableView, so we don't need any of this
它有所有这些UITableView,所以我们不需要这些

1040
00:49:19,256 --> 00:49:20,790
stuff as you're gonna see here,
你会看到,

1041
00:49:24,395 --> 00:49:27,896
This is our new TableViewController,
这是我们的新表,

1042
00:49:27,965 --> 00:49:28,897
Let's go ahead and
让我们继续

1043
00:49:28,966 --> 00:49:31,267
update our storyboard to segue to this thing,
更新我们的故事板segue这个东西,

1044
00:49:31,335 --> 00:49:33,202
So we'll go over here,
所以我们会在这里,

1045
00:49:33,271 --> 00:49:36,138
Let's create our bar button item to do the segue, so
让我们创建工具栏按钮segue,

1046
00:49:36,206 --> 00:49:38,139
I'm gonna search here for button,
我要在这里搜索按钮,

1047
00:49:38,208 --> 00:49:40,742
You never wanna put a button in here,
在这里,你永远不会想要把一个按钮

1048
00:49:40,811 --> 00:49:45,246
it'll look like it's gonna working, but it's not right,
它会看起来像它会工作,但它是不正确的,

1049
00:49:45,315 --> 00:49:47,316
Put a bar button in a bar,
在酒吧里放一个工具栏按钮,

1050
00:49:49,553 --> 00:49:52,821
So we'll call this Tweeter cuz that's what it shows, it shows
所以我们称之为推特因为这就是它所示,它显示了

1051
00:49:52,889 --> 00:49:55,725
the tweeters that tweeted all the tweets in this table,
推特,推特这个表的所有微博,

1052
00:49:56,961 --> 00:49:59,995
Let's get a TableViewController out,
,让我们一个表

1053
00:50:00,064 --> 00:50:04,733
here it is,
在这里,

1054
00:50:04,802 --> 00:50:07,203
TableViewController right there,
表,

1055
00:50:07,271 --> 00:50:09,805
Lets go ahead and segue from this,
让我们继续,继续,

1056
00:50:09,874 --> 00:50:11,606
Ctrl + drag,
Ctrl +拖,

1057
00:50:11,675 --> 00:50:14,543
Show segue, we're inside a navigation controller here,
显示segue,我们这里在导航控制器,

1058
00:50:14,612 --> 00:50:18,747
Let's set this segue identifier, we'll call this,
设这个segue标识符,我们叫这个,

1059
00:50:18,816 --> 00:50:19,682
what did I?
我什么?

1060
00:50:19,751 --> 00:50:20,715
I had a good name for this,
我有一个好名字,

1061
00:50:20,784 --> 00:50:25,620
Yes, Tweeters Mentioning Search Term,
是的,高音提到搜索词,

1062
00:50:25,689 --> 00:50:26,788
Cuz that's what this segue does,
因为这是这个segue做什么,

1063
00:50:26,857 --> 00:50:29,792
It show the tweeters that have mentioned this search
它显示了高音,提到这个搜索

1064
00:50:29,860 --> 00:50:31,160
term right here,
一项,

1065
00:50:31,228 --> 00:50:34,964
Let's also have our little cell here be a subtitle cell,
我们也有我们的小细胞是一个副标题细胞,

1066
00:50:35,032 --> 00:50:37,166
So we'll change that to subtitle,
所以我们会改变字幕,

1067
00:50:37,234 --> 00:50:39,401
And we need a reuse identifier for this cell right here,
我们需要一个重用标识符这个细胞,

1068
00:50:39,470 --> 00:50:43,939
We'll call this a TwitterUser Cell, cuz that's what it is,
我们称之为TwitterUser细胞,因为它是什么,

1069
00:50:44,007 --> 00:50:47,376
The Twitter user gonna be shown in this cell right here,
所示的Twitter用户将这个细胞,

1070
00:50:47,445 --> 00:50:48,077
All right, so that's it,
好吧,就是这样,

1071
00:50:48,145 --> 00:50:50,645
That's our entire UI,
这是我们整个用户界面,

1072
00:50:50,714 --> 00:50:51,613
Super simple,
超级简单,

1073
00:50:51,682 --> 00:50:54,817
All we need to do now is implement the guts of
现在我们需要做的就是实现的勇气

1074
00:50:54,886 --> 00:50:56,217
this controller right here,
这个控制器,

1075
00:50:56,286 --> 00:50:58,153
So let's go back to that,
让我们回到,

1076
00:50:58,221 --> 00:51:00,922
Here it is right here,
这是在这里,

1077
00:51:00,991 --> 00:51:03,325
Let's talk about the public API,
让我们来谈谈公共API,

1078
00:51:03,394 --> 00:51:04,860
I just really want to get in the habit of this,
我只是想的习惯,

1079
00:51:04,928 --> 00:51:07,763
Every time we introduce a new MVC, let's talk about it,
每次我们引入一个新的MVC,让我们谈论它,

1080
00:51:07,831 --> 00:51:09,297
its public API,
它的公共API,

1081
00:51:09,366 --> 00:51:11,767
So this SmashTweetersTableViewControl-
所以这SmashTweetersTableViewControl -

1082
00:51:11,836 --> 00:51:14,369
ler, really has two parts in its model,
l,真的有两个部分的模型,

1083
00:51:14,438 --> 00:51:18,474
One is, it needs to know the mention, the search term that
一个是,它需要知道提到,搜索词

1084
00:51:18,542 --> 00:51:22,911
its supposed to be showing the Tweeters for, so I'm gonna
它应该显示的高音,所以我要

1085
00:51:22,980 --> 00:51:26,748
have, I'll call it mention, which is just a string,
我叫它提到,这是一个字符串,

1086
00:51:26,817 --> 00:51:28,817
So that's part of its public model, and then,
这就是公共模型的一部分,然后,

1087
00:51:28,885 --> 00:51:30,553
what's the other part of its model?
另一部分的模型是什么?

1088
00:51:31,522 --> 00:51:33,355
The database,
数据库,

1089
00:51:35,059 --> 00:51:37,092
What it does is look up in the database and
它是在数据库中查找和

1090
00:51:37,161 --> 00:51:39,661
find tweeters who mention this in their tweets,
发现高音提到这个在他们的微博,

1091
00:51:39,730 --> 00:51:44,166
So it's gotta have an NSPersistentContainer here,
所以要有一个NSPersistentContainer这里,

1092
00:51:44,235 --> 00:51:50,139
By the way, some people, import CoreData,
顺便说一下,有些人,进口CoreData,

1093
00:51:50,207 --> 00:51:52,574
Instead of having the database represented in the public
而不是代表在公共的数据库

1094
00:51:52,643 --> 00:51:54,376
model here as a container,
模型是一个容器,

1095
00:51:54,445 --> 00:51:57,212
they might just pass the context only,
他们可以通过上下文,

1096
00:51:57,281 --> 00:51:59,648
If they pass the context only here though,
不过,如果他们只通过上下文这里

1097
00:51:59,716 --> 00:52:01,683
you can't do any background stuff,
你不能做任何背景的东西,

1098
00:52:01,752 --> 00:52:04,119
So I like to pass, pass the container here,
所以我想通过,通过这里的容器,

1099
00:52:04,188 --> 00:52:07,690
Plus, this whole thing is a UI element,
另外,这整个事情是一个UI元素,

1100
00:52:07,758 --> 00:52:10,625
so it wants to use a view context,
所以想要使用一个视图上下文,

1101
00:52:10,694 --> 00:52:13,295
No other context cuz it does its stuff all on the main
因为它没有其他上下文对最主要的东西

1102
00:52:13,364 --> 00:52:14,830
queue, it's a UI,
队列,这是一个用户界面,

1103
00:52:14,899 --> 00:52:17,466
So it's nice when you pass a container cuz you're gonna ask
所以很高兴当你通过容器因为你会问

1104
00:52:17,535 --> 00:52:18,534
for the view context and
的背景和观点

1105
00:52:18,603 --> 00:52:20,669
you know you're getting a main queue context,
你知道你得到一个主要的队列上下文,

1106
00:52:20,738 --> 00:52:23,238
Where if someone passes a context in here,
如果有人在这里,通过上下文

1107
00:52:23,306 --> 00:52:27,008
could be not be a main queue context, that could be bad,
可能不是一个主要的队列上下文,可能是坏的,

1108
00:52:27,077 --> 00:52:30,612
So I think a container is a good wrapper when you want to
所以我认为一个容器是一个很好的包装当你想

1109
00:52:30,681 --> 00:52:33,949
tell an MVC this is the database to use to do what you
告诉MVC是做你所使用的数据库

1110
00:52:34,017 --> 00:52:35,584
do, here it is,
在这里,

1111
00:52:35,653 --> 00:52:39,788
And sure we'll do our little trick here where we make
当然我们会做我们这里的小技巧

1112
00:52:39,856 --> 00:52:40,723
a default,
缺省情况下,

1113
00:52:40,791 --> 00:52:44,259
(UIApplication,shared,delegete as?
(UIApplication,共享,delegete吗?

1114
00:52:44,328 --> 00:52:49,264
AppDelegate)?,persistentConta- iner,
AppDelegate)?

1115
00:52:49,333 --> 00:52:54,770
You don't even really have to do this but we'll do it,
你甚至不需要这样做,但我们将这样做,

1116
00:52:56,139 --> 00:53:00,341
So that's basically our model and
这就是我们的模型

1117
00:53:00,410 --> 00:53:03,912
anytime our model changes,
在我们的模型的变化,

1118
00:53:03,981 --> 00:53:10,719
I'm gonna have a didSet here that updates my UI,
我要在这里有一个didSet更新我的界面,

1119
00:53:10,788 --> 00:53:12,655
We'll do the same thing,
我们会做同样的事情,

1120
00:53:13,824 --> 00:53:14,723
If I can select it,
如果我可以选择的话,

1121
00:53:14,792 --> 00:53:16,692
do the same thing with this guy right here,
与这个东西,做同样的事情

1122
00:53:19,029 --> 00:53:22,331
We need a private func to do that,
我们需要一个私有函数,

1123
00:53:24,901 --> 00:53:30,372
So this is our model, and it's UI updating,
这是我们的模型,它的UI更新

1124
00:53:30,440 --> 00:53:32,974
Now before I go implement this UI updating,
现在我去实现这个UI更新之前,

1125
00:53:33,043 --> 00:53:34,343
cuz it's pretty straightforward,
因为它很简单,

1126
00:53:34,411 --> 00:53:38,314
I'm gonna back to my SmashTweetTableViewController,
我要回到我的SmashTweetTableViewController,

1127
00:53:38,382 --> 00:53:40,482
the one that's gathering all the statistics,
收集所有的数据,

1128
00:53:40,551 --> 00:53:42,985
because that's also the one I'm segueing from,
因为这也是我segue从,

1129
00:53:44,021 --> 00:53:45,687
This smash, this one right here,
这个,这粉碎

1130
00:53:45,755 --> 00:53:47,356
Smash Tweet Table View Controller,
粉碎推表视图控制器,

1131
00:53:47,424 --> 00:53:49,625
I'm segueing from this to this using this button,
我从这segue使用这个按钮,

1132
00:53:49,694 --> 00:53:51,893
So that's where the prepare needs to be,
这是需要准备的,

1133
00:53:51,962 --> 00:53:54,129
So I'm gonna put the prepare in here for that,
所以我要把这里的准备,

1134
00:53:54,198 --> 00:53:56,364
So let's put the prepare down at the bottom here,
我们将准备在底部,

1135
00:53:56,433 --> 00:54:00,802
prepare (for segue:,
准备(:,

1136
00:54:00,871 --> 00:54:01,603
Here it is, Now,
在这里,现在,

1137
00:54:01,672 --> 00:54:04,173
I'm gonna go through this really fast because you guys
我要通过这个非常快,因为你们

1138
00:54:04,242 --> 00:54:06,208
surely know prepare (for segue: by now,
肯定知道准备(segue:到目前为止,

1139
00:54:06,276 --> 00:54:09,745
I mean to say if the segue:identifier is what
我的意思是说如果segue:标识符是什么

1140
00:54:09,813 --> 00:54:11,045
I said which is,
我是说,

1141
00:54:11,114 --> 00:54:15,217
and again I should make a constant here but for speed,
我应该做一个常数但是速度,

1142
00:54:15,285 --> 00:54:18,753
so this is Tweeters Mentioning Search Term,
这是高音提到搜索词,

1143
00:54:18,822 --> 00:54:21,489
that's what I called that segue,
这就是我称之为segue,

1144
00:54:21,558 --> 00:54:23,592
Then I'm going to get the destination,
然后我将得到目的地,

1145
00:54:23,661 --> 00:54:28,363
So that is a TweetersTableViewController =
这是一个TweetersTableViewController =

1146
00:54:28,431 --> 00:54:31,233
segues,destination as?
segues目的地,as ?

1147
00:54:31,301 --> 00:54:35,604
SmashTweetersTableViewControl- ler,
SmashTweetersTableViewControl - l,

1148
00:54:35,673 --> 00:54:38,840
And yeah, I could probably do ContentViewController here,
是的,我可以在这里做ContentViewController,

1149
00:54:38,909 --> 00:54:41,810
because if I had that extension in here, because
因为在这里,如果我有,扩展

1150
00:54:41,879 --> 00:54:44,913
maybe I want to put this in a split view someday and etc,
也许我想把它拆分视图有一天等,

1151
00:54:44,982 --> 00:54:47,849
But first time I won't do that,
但是第一次我不会这样做,

1152
00:54:47,918 --> 00:54:50,418
So now I've got the tweetersTVC,
所以现在我有tweetersTVC,

1153
00:54:50,487 --> 00:54:51,954
This is my TweetersTableViewController,
这是我的TweetersTableViewController,

1154
00:54:52,022 --> 00:54:53,922
I'm just gonna set its public API,
我要设置它的公共API,

1155
00:54:53,991 --> 00:54:56,791
TweetersTVC,mention,
TweetersTVC提到,

1156
00:54:56,860 --> 00:55:01,997
Mention equals my search term,
提到=我的搜索词,

1157
00:55:02,066 --> 00:55:05,200
This is the MVC where you type the text in so
这就是你输入MVC中的文本

1158
00:55:05,269 --> 00:55:06,602
it has search text,
搜索文本,

1159
00:55:06,671 --> 00:55:10,271
And then the tweetersTVC,container equals
然后tweetersTVC,容器=

1160
00:55:10,340 --> 00:55:11,539
my container,
我的容器,

1161
00:55:11,608 --> 00:55:12,640
I have the same one,
我也有同样的一个,

1162
00:55:12,709 --> 00:55:15,877
The tweeters MVC looking in the same database I'm
高音MVC相同的数据库我看

1163
00:55:15,946 --> 00:55:16,811
looking in,
在看,

1164
00:55:16,880 --> 00:55:19,915
So here I am actually setting this thing,
所以我在这里实际上设置这个东西,

1165
00:55:19,983 --> 00:55:22,217
We got an error here, what is it?
我们这里有一个错误,它是什么?

1166
00:55:22,285 --> 00:55:24,452
Tweeters, okay,
Tweeters,好吧,

1167
00:55:24,521 --> 00:55:27,989
All right, so I'm just setting my public model of
好吧,我只是设置的公共模型

1168
00:55:28,058 --> 00:55:32,393
my Tweeters, not Tweet, TweetersTableViewController,
我的推特,不是微博,TweetersTableViewController

1169
00:55:32,462 --> 00:55:33,962
SImple enough,
很简单,

1170
00:55:34,031 --> 00:55:37,332
All right, now that we are all ready to segue to this nice
好吧,既然我们都准备segue这个不错

1171
00:55:37,400 --> 00:55:40,668
SmashTableViewController, how do we update its UI?
SmashTableViewController,我们如何更新它的UI ?

1172
00:55:40,737 --> 00:55:43,138
How do we get it to look in CoreData,
我们如何让它看CoreData,

1173
00:55:43,206 --> 00:55:46,975
find the Twitter users that have tweeted something that
找到的Twitter用户在推特上的东西

1174
00:55:47,044 --> 00:55:49,411
matches this mention and show it?
匹配这提及并展示吗?

1175
00:55:49,479 --> 00:55:51,079
Well, there's really,
有真的,

1176
00:55:51,147 --> 00:55:53,681
we're gonna use NS Fetched Results Controller, of course,
我们将使用NS控制器获取结果,当然,

1177
00:55:53,750 --> 00:55:55,984
that's the main deal here,
这是这里的主要协议,

1178
00:55:56,053 --> 00:55:58,954
And what are the pieces we need to do?
件我们需要做的是什么?

1179
00:55:59,023 --> 00:56:01,823
This was the last slide from the last lecture,
这是上节课的最后一张幻灯片,

1180
00:56:01,892 --> 00:56:05,460
I hope you all remember it, it was very recent,
我希望你们记住它,它很近,

1181
00:56:05,528 --> 00:56:09,264
First thing is we have to have this table-view controller
第一件事是我们必须有这个表格视图控制器

1182
00:56:09,332 --> 00:56:12,935
be an NS-fetched-result-controller
是一个NS-fetched-result-controller

1183
00:56:13,003 --> 00:56:13,836
If you're going to use a fetched results controller
如果你想使用一个控制器获取结果

1184
00:56:13,837 --> 00:56:14,670
delegate,
委托,

1185
00:56:14,738 --> 00:56:17,505
your table needs to be the delegate of that fetched
你的表需要获取的委托

1186
00:56:17,574 --> 00:56:20,008
controller, and I told you I was going to help you out with
控制器,我告诉过你我要帮助你

1187
00:56:20,077 --> 00:56:23,212
that and provide that code and sure enough I am,
,并提供代码,果然,我

1188
00:56:23,280 --> 00:56:23,845
It's right here,
就在这里,

1189
00:56:23,914 --> 00:56:28,550
I'm gonna drag it in somewhere, copy it in, yes,
我要把它拖到某处,复制它,是的,

1190
00:56:30,220 --> 00:56:33,255
All right, and let's take a look at it, here it is,
好吧,让我们看看,在这里,

1191
00:56:33,324 --> 00:56:35,824
FetchedResultsTableViewContro- ller,
FetchedResultsTableViewContro——噢,

1192
00:56:35,893 --> 00:56:38,293
You can see that it is a subclass of
你可以看到它的子类

1193
00:56:38,362 --> 00:56:40,796
UITableViewController that implements the
UITableViewController实现

1194
00:56:40,865 --> 00:56:43,398
NSFetchedResultsControllerDel- egate protocol,
NSFetchedResultsControllerDel egate协议,

1195
00:56:43,467 --> 00:56:46,001
So these are the methods right here in our protocol,
所以这些方法在我们的协议,

1196
00:56:46,070 --> 00:56:47,702
there are four of them,
有四个,

1197
00:56:47,771 --> 00:56:51,139
You can see that it is just using table view methods
你可以看到它是使用表格视图的方法

1198
00:56:51,208 --> 00:56:52,975
to update the table,
更新表,

1199
00:56:53,043 --> 00:56:55,810
These controller methods get called whenever the NS
这些控制器方法被调用时NS

1200
00:56:55,879 --> 00:56:59,414
Fetched Result Controller notices the database change
获取结果控制器通知数据库变更

1201
00:56:59,483 --> 00:57:01,650
in a way that would affect the NS Fetched Result,
在某种程度上影响NS获取结果,

1202
00:57:03,153 --> 00:57:04,652
So this is the magic that makes your table
这是一个神奇的让你的表

1203
00:57:04,721 --> 00:57:06,521
automatically update when the database changes,
自动更新数据库时的变化,

1204
00:57:06,590 --> 00:57:09,190
You don't have to do anything, it just automatically updates,
你不需要做任何事情,它就自动更新,

1205
00:57:09,259 --> 00:57:11,025
It's because of this delegate,
因为这个委托的,

1206
00:57:11,094 --> 00:57:14,696
Now, for our thing to work we need to be a subclass of this,
现在,我们需要对我们的工作的一个子类,

1207
00:57:14,764 --> 00:57:17,399
so that we inherit all this stuff,
这样我们继承这些东西,

1208
00:57:17,468 --> 00:57:19,335
we're just going to go back to our smashTweeters here and
我们将回到我们的smashTweeters这里

1209
00:57:19,336 --> 00:57:21,203
So that's easy,
这很简单,

1210
00:57:21,272 --> 00:57:22,938
instead of being a UITableViewController,
而不是一个UITableViewController,

1211
00:57:23,006 --> 00:57:25,139
I'm gonna be a FetchedResultsTableViewContro-
我要一个FetchedResultsTableViewContro -

1212
00:57:25,208 --> 00:57:28,110
ller, simple,
简单、默勒

1213
00:57:28,178 --> 00:57:31,012
So, that's the easy way to become
所以,这是最简单的方式

1214
00:57:31,081 --> 00:57:33,114
a FetchedResultsController delegate,
一个,FetchedResultsController委托,

1215
00:57:33,183 --> 00:57:34,616
Now, what was the next thing we need to do?
现在,接下来我们需要做的是什么?

1216
00:57:34,685 --> 00:57:37,452
We have to implement all of our UITableViewDataSource
我们要实现我们所有的需要

1217
00:57:37,521 --> 00:57:41,689
Methods using a fetchedResultsController,
方法使用,fetchedResultsController,

1218
00:57:41,758 --> 00:57:43,258
So there's two parts to that,
有两个部分,

1219
00:57:43,327 --> 00:57:45,793
One is we need to create a var, which is
一个是我们需要创建一个var,

1220
00:57:45,862 --> 00:57:51,099
a fetchedResultsController controller,
,fetchedResultsController控制器,

1221
00:57:51,168 --> 00:57:54,136
It's going to be a type NSFetchedResultsController,
这将是一种NSFetchedResultsController,

1222
00:57:58,541 --> 00:58:01,877
It's FetchResultsController that fetches tweeter users,
FetchResultsController获取的推特用户,

1223
00:58:04,147 --> 00:58:06,615
So FetchResultsController is also generic type and
所以FetchResultsController也是泛型类型

1224
00:58:06,683 --> 00:58:09,184
you have to say what kind of thing does it fetch?
你说什么东西卖吗?

1225
00:58:09,252 --> 00:58:12,053
So I've got this var, how do I implement all
所以我有这个var,如何实现

1226
00:58:12,122 --> 00:58:13,721
those UI table of your data source methods as well?
这些UI数据源表方法吗?

1227
00:58:13,790 --> 00:58:15,890
Well, I can type them all in but you know what,
好吧,我可以输入他们所有人,但你知道吗,

1228
00:58:15,959 --> 00:58:18,960
it's exactly the same in every single to every single time
在每一个完全相同的每一次

1229
00:58:19,029 --> 00:58:21,663
you implement one of these the code is exactly the same
实现一个完全相同的代码

1230
00:58:21,732 --> 00:58:22,897
because fetchedResultsController
因为,fetchedResultsController

1231
00:58:22,966 --> 00:58:25,700
always answers those questions in exactly the same way,
总是以完全相同的方式回答这些问题,

1232
00:58:25,768 --> 00:58:26,901
So you could copy and
所以你可以复制和

1233
00:58:26,970 --> 00:58:29,404
paste it from some other half that you've done or
粘贴在其他一些你所做的一半

1234
00:58:29,473 --> 00:58:31,706
you could use this little beauty that I've created for
你可以用这个小美女,我创建了

1235
00:58:31,775 --> 00:58:35,210
you right here, another little thing you can drag in,
你在这里,另一个小东西你可以拖拽,

1236
00:58:35,279 --> 00:58:36,211
which we'll take a look,
我们会看一看,

1237
00:58:36,279 --> 00:58:40,949
Copy that, and this is an extension
复制,这是一个扩展

1238
00:58:41,018 --> 00:58:45,354
that you can extend your class,
你能扩展你的类,

1239
00:58:45,422 --> 00:58:46,188
So in this case,
所以在这种情况下,

1240
00:58:46,256 --> 00:58:50,092
it's our smash tweeters tableviewController,
这是我们粉碎,高音表

1241
00:58:50,160 --> 00:58:51,359
And in this extension,
在这个扩展,

1242
00:58:51,428 --> 00:58:55,330
it adds all the UI tableview data source methods,
它增加了所有uitableview数据源方法,

1243
00:58:56,333 --> 00:58:57,365
See,
看到的,

1244
00:58:57,434 --> 00:58:59,434
And implements them in terms of your
和你的来实现

1245
00:58:59,503 --> 00:59:01,069
fetchresultscontroller,
fetchresultscontroller,

1246
00:59:01,138 --> 00:59:04,172
Now, this extension will not compile if you do not have
现在,这个扩展将不会编译如果你没有

1247
00:59:04,241 --> 00:59:07,508
a fetch results controller because extensions can't add
获取结果控制器,因为扩展不能添加

1248
00:59:07,577 --> 00:59:10,812
any storage themselves so you have to have the storage be in
任何存储自己所以你需要存储

1249
00:59:10,881 --> 00:59:14,382
your class but this class does have fetch result controller,
你的类,但这类获取结果控制器,

1250
00:59:14,451 --> 00:59:18,386
Now, the one thing it doesn't implement here though is
现在,这里是没有实现

1251
00:59:18,455 --> 00:59:22,357
cellForRowAt cuz cellForRowAt add is specific to whatever
cellForRowAt因为cellForRowAt添加特定于任何

1252
00:59:22,426 --> 00:59:24,993
data you're showing in the table but
但你的数据显示在表

1253
00:59:25,062 --> 00:59:29,064
even cellForRowAt, if we go back here and do cellForRowAt,
即使cellForRowAt,如果我们回到这里,做cellForRowAt,

1254
00:59:29,133 --> 00:59:33,835
let's do that so cellForRowAt index path more with,
做一下所以cellForRowAt索引路径,

1255
00:59:33,904 --> 00:59:35,436
And, of course, we know how to do that right,
当然,我们知道怎么做吧,

1256
00:59:35,505 --> 00:59:40,542
let the cell equal to tableView deque this one,
让细胞等于tableView双端队列,

1257
00:59:40,611 --> 00:59:45,880
and the Identifier was "TwitterUser Cell" I believe,
标识符是“TwitterUser单元”我相信,

1258
00:59:45,949 --> 00:59:47,315
correct me if I'm wrong,
纠正我如果我错了,

1259
00:59:47,383 --> 00:59:50,151
And we want IndexPath there, so I got the cell, and
我们希望IndexPath那里,所以我得到了细胞,

1260
00:59:50,220 --> 00:59:51,586
we return the cell,
我们返回的细胞,

1261
00:59:51,654 --> 00:59:52,587
And in between,
在之间,

1262
00:59:52,655 --> 00:59:57,025
I need to load the cell up with its various information,
我需要负载细胞和它的各种信息,

1263
00:59:57,094 --> 00:59:59,627
Now we set our cell to be, if you remember,
现在我们组细胞,如果你还记得,

1264
00:59:59,696 --> 01:00:01,196
a Subtitle cell, right?
一个副标题细胞,对吧?

1265
01:00:01,265 --> 01:00:03,231
This is a Subtitle cell,
这是一个副标题细胞,

1266
01:00:03,300 --> 01:00:06,668
So we can set its TextLabel and its detailTextLabel,
所以我们可以设置其TextLabel及其detailTextLabel

1267
01:00:06,736 --> 01:00:08,904
So let's just start with just the TextLabel,
让我们开始TextLabel,

1268
01:00:08,973 --> 01:00:14,175
So I wanna set the cell,textLabels Text,
我想设置单元,textLabels文本,

1269
01:00:14,244 --> 01:00:19,814
basically equal to the twitter uses handle,
基本上等于twitter使用句柄,

1270
01:00:19,883 --> 01:00:23,051
But I have to get the twitter user that's in this row,
但是我必须让twitter用户在这一行,

1271
01:00:24,288 --> 01:00:26,254
Okay, how do I find the twitter user
好了,我怎么找到twitter用户

1272
01:00:26,323 --> 01:00:27,121
that's in the role?
的作用?

1273
01:00:27,190 --> 01:00:30,192
I'm gonna ask my fetch results controller,
我要问一下我取回结果控制器,

1274
01:00:30,260 --> 01:00:33,595
Let the twitter user in this role,
让这个角色的twitter用户,

1275
01:00:33,664 --> 01:00:37,299
in this row, equal my fetch results controller
在这一行,等于我取回结果控制器

1276
01:00:38,568 --> 01:00:40,235
which might be null cuz it's an optional,
这可能是零因为它是一个可选的,

1277
01:00:40,303 --> 01:00:45,640
Object(at: indexPath),
对象(:indexPath),

1278
01:00:45,709 --> 01:00:50,178
And since this could be nil because this could be nil
因为这可能是零,因为这可能是零

1279
01:00:50,247 --> 01:00:55,517
right here let's do if let, then we will update our cell,
如果让我们做,然后我们将更新我们的细胞,

1280
01:00:57,987 --> 01:01:00,054
Now if we didn't have a fetchedResultsController,
如果我们没有,fetchedResultsController,

1281
01:01:00,123 --> 01:01:02,090
by the way, if this were nil, our number of rows and
顺便说一下,如果这是零,我们的行数

1282
01:01:02,159 --> 01:01:03,625
sections would be zero all the time,
部分将是零,

1283
01:01:03,694 --> 01:01:04,559
This would never be called,
这永远不会被称为,

1284
01:01:04,627 --> 01:01:07,095
So we can even put an exclamation point here,
所以我们甚至可以把感叹号,

1285
01:01:07,163 --> 01:01:08,730
And maybe we should put an exclamation point here
也许我们应该把一个感叹号

1286
01:01:08,799 --> 01:01:11,499
because this should never be called if this is nil,
因为这个不应该被称为如果这是零,

1287
01:01:11,567 --> 01:01:14,702
But anyway, so it's this very simple method, object)at:,
但无论如何,这是非常简单的方法,对象):

1288
01:01:14,771 --> 01:01:17,873
is gonna return you the thing of the type
你会返回类型的东西吗

1289
01:01:17,941 --> 01:01:19,774
that it's controlling, which is Twitter user,
它的控制,这是Twitter用户,

1290
01:01:19,843 --> 01:01:21,176
And if we look at the type here,
如果我们看看类型,

1291
01:01:21,244 --> 01:01:24,179
you can see that's a Twitter user that goes at this
你可以看到这是一个Twitter用户

1292
01:01:24,248 --> 01:01:24,812
index path,
索引路径,

1293
01:01:24,881 --> 01:01:26,213
So that row and that section,
这一行和这部分,

1294
01:01:26,282 --> 01:01:27,582
So it could not be easier,
所以它不能简单,

1295
01:01:27,651 --> 01:01:29,851
And now we can just, in here, update whatever you or
现在我们可以,在这里,不管你或更新

1296
01:01:29,920 --> 01:01:31,620
I want, no matter how complicated it is,
我希望,不管它有多复杂,

1297
01:01:31,688 --> 01:01:33,521
We've got the Twitter user that's showing there, so
我们有显示的Twitter用户,所以

1298
01:01:33,590 --> 01:01:36,424
we can his handle, his username, whatever else,
我们可以处理,用户名,其他,

1299
01:01:36,493 --> 01:01:38,727
We wanna get on him and put it in there,
我们想要在他身上,把它放在那里,

1300
01:01:40,497 --> 01:01:42,297
Everybody got that?
大家都明白了吗?

1301
01:01:42,366 --> 01:01:43,298
Super simple, and
超级简单,

1302
01:01:43,367 --> 01:01:46,400
yes it is super simple that's what's great about in fetch
是的它是超级简单,就是伟大的取回

1303
01:01:46,469 --> 01:01:49,304
results controller is that really the amount of code we
结果控制器是我们真正的代码数量

1304
01:01:49,373 --> 01:01:52,641
actually had to write here is absolutely tiny,
有写在这里绝对是小,

1305
01:01:52,709 --> 01:01:56,244
Now, there is one piece left which is update UI so
现在,还有一块是更新UI

1306
01:01:56,313 --> 01:01:59,648
when someone sets our mention or sets our database,
当有人集我们提到或设置数据库,

1307
01:01:59,716 --> 01:02:03,584
we need to create a fetch results controller, obviously,
我们需要创建一个控制器获取结果,显然,

1308
01:02:03,653 --> 01:02:05,353
Just can't be nil all the time,
不能是零,

1309
01:02:05,421 --> 01:02:07,555
we actually have to create one and we're just gonna say,
我们必须创建一个和我们只是想说,

1310
01:02:07,624 --> 01:02:13,495
fetchResultsController = a new
fetchResultsController =一个新的

1311
01:02:13,563 --> 01:02:18,567
NSFetchedResultsController, which is for Twitter users,
NSFetchedResultsController,Twitter用户,

1312
01:02:20,804 --> 01:02:24,939
And we will use this constructor right here,
我们将使用这个构造函数,

1313
01:02:25,008 --> 01:02:27,208
I'll go ahead and separate this out so
我要独立出来

1314
01:02:27,277 --> 01:02:29,410
you can see a little better what the arguments are,
你可以看到一个更好的理由是什么,

1315
01:02:29,479 --> 01:02:31,379
Let me see from this slide as well,
让我看看从这张幻灯片,

1316
01:02:33,350 --> 01:02:35,182
So what are the four things we need?
那么我们需要的四件事是什么呢?

1317
01:02:35,251 --> 01:02:38,486
We need a request, I'll make a request,
我们需要一个请求,我将做一个请求,

1318
01:02:38,555 --> 01:02:41,923
We need a context, I'll make a context,
我们需要一个环境,我将做一个背景下,

1319
01:02:41,991 --> 01:02:46,561
We need the name of the var in TwitterUser,
我们需要在TwitterUser var的名称,

1320
01:02:46,630 --> 01:02:48,829
that says this section title,
说本节标题,

1321
01:02:48,898 --> 01:02:50,698
Well, we don't have any sections all our Twitter users
好吧,我们没有任何部分我们所有的Twitter用户

1322
01:02:50,767 --> 01:02:52,567
are gonna be shown in one big like long list,
会显示在一个大长串,

1323
01:02:52,636 --> 01:02:55,003
so that's nil and we won't cache our results,
这是零,我们不会缓存结果,

1324
01:02:55,071 --> 01:02:58,473
Although we could, because we're never gonna change this
虽然我们可以,因为我们不会改变这一现状

1325
01:02:58,542 --> 01:03:01,375
request--well, actually that's not true,
请求,其实那不是真的,

1326
01:03:01,444 --> 01:03:03,345
We could change this because someone might
我们可以改变这个,因为有人会

1327
01:03:03,413 --> 01:03:05,647
bring up this MVC and then change the mention and
把这MVC然后改变提及

1328
01:03:05,715 --> 01:03:07,949
that would be changing the request to look for different
这将是改变请求不同

1329
01:03:08,018 --> 01:03:10,484
twitter users so it's better not to catch this beside
twitter用户最好不要抓这个旁边

1330
01:03:10,553 --> 01:03:13,221
the results are hopefully gonna be fairly small,
希望结果会是相当小的,

1331
01:03:13,290 --> 01:03:15,123
So I have to do a request in context here,
所以我要做一个请求上下文,

1332
01:03:15,192 --> 01:03:16,257
Let's do context first,
让我们先做背景,

1333
01:03:16,326 --> 01:03:19,895
I'm gonna say if I can let my context equal my containers
我想说如果我可以让我的上下文相同的容器中

1334
01:03:22,365 --> 01:03:23,631
View context,
视图的背景下,

1335
01:03:23,700 --> 01:03:26,634
Now, this is very important right here to use
现在,这是非常重要的

1336
01:03:26,703 --> 01:03:29,837
view context because this is a Ui thing,
视图上下文Ui的事情,因为这是一个

1337
01:03:29,906 --> 01:03:32,473
And this fetch results controller is gonna be working
这取结果控制器会工作

1338
01:03:32,542 --> 01:03:34,909
with our table view controller, that's all UI so
与我们的表格视图控制器,这是所有UI

1339
01:03:34,978 --> 01:03:36,778
we wanna do this all in the main queue,
我们想在主队列做这一切,

1340
01:03:36,846 --> 01:03:39,881
So, you have to use view context,
所以,你必须使用视图上下文,

1341
01:03:39,949 --> 01:03:42,417
You cannot do that background thing
你不能这样做背景

1342
01:03:42,486 --> 01:03:43,918
to create your FetchResultController,
创建你的FetchResultController,

1343
01:03:43,987 --> 01:03:47,389
All right, so all that leaves is this request here so
好吧,这是所有的叶子请求这里

1344
01:03:47,457 --> 01:03:50,758
I'm gonna let the request it's obviously going to
我要让它显然会请求

1345
01:03:50,827 --> 01:03:53,829
be an NSFetchRequest for Twitter users,
是一个NSFetchRequest Twitter用户,

1346
01:03:56,099 --> 01:03:58,633
And we use this nice convenience thing here
我们使用这个方便的事情

1347
01:03:58,702 --> 01:04:02,571
TwitterUser,FetchRequest and so what does our request need?
TwitterUser,FetchRequest和我们的要求需要什么?

1348
01:04:02,639 --> 01:04:06,374
Well, our request needs sort descriptors, so
嗯,我们的要求需要描述符,所以

1349
01:04:06,442 --> 01:04:09,210
we're gonna have to have some array of sort descriptors,
我们要有一系列的描述符,

1350
01:04:09,278 --> 01:04:11,279
Our request also needs a predicate,
我们的要求也需要一个谓词,

1351
01:04:11,347 --> 01:04:19,153
Predicate,
谓词,

1352
01:04:19,222 --> 01:04:25,660
Whoops, gotta get format right here, this one,
哎呀,这里得格式,这一个,

1353
01:04:27,530 --> 01:04:29,831
We're gonna have to have some format string there, and
我们会有一些格式字符串,和

1354
01:04:29,900 --> 01:04:33,067
then some args for the percent at signs,
然后一些args的百分比的迹象,

1355
01:04:33,136 --> 01:04:34,936
So let's do this sort descriptor first,
让我们先做这类描述符,

1356
01:04:35,004 --> 01:04:37,305
We're looking for all the Twitter users who have tweeted
我们正在寻找所有的Twitter用户

1357
01:04:37,373 --> 01:04:39,507
something that mentioned that search for a minute,
提到搜索一下,

1358
01:04:39,576 --> 01:04:43,444
Let's order them by their handle, at sign whatever,
我们命令他们处理,在任何迹象,

1359
01:04:43,513 --> 01:04:47,848
So all we need to do then is say, NSSortDescriptor with and
那么我们需要做的是说,NSSortDescriptor和

1360
01:04:47,917 --> 01:04:50,084
we'll use the one with the key,
我们将使用的关键,

1361
01:04:50,153 --> 01:04:56,957
It's not, it's going to make me type it, arg,
它不是,它会让我输入,参数,

1362
01:04:57,026 --> 01:05:03,364
So we'll do the key handle and we'll do ascending true,
所以我们要做的关键处理,我们会提升真的,

1363
01:05:03,433 --> 01:05:05,299
That's good enough, we'll just have it sort however it sorts,
那已经足够好了,我们就把它但是它,

1364
01:05:05,368 --> 01:05:08,002
We'll come back to sorting later and look at it,
我们将回到排序后,看着它,

1365
01:05:08,071 --> 01:05:09,704
We only need one sort descriptor we're not gonna
我们只需要一个描述符我们不会

1366
01:05:09,773 --> 01:05:11,573
sort by the a handle and
一个句柄和排序

1367
01:05:11,641 --> 01:05:14,041
then subsort by something else because the handle will be
然后由其他东西,因为subsort处理

1368
01:05:14,110 --> 01:05:17,345
sufficient sorting in there, and what about our predicate?
足够的排序,和我们的谓语呢?

1369
01:05:17,414 --> 01:05:20,214
What tweeter users are we looking for here?
推特用户我们在这里找什么?

1370
01:05:20,283 --> 01:05:22,783
This is really the key to making anything work and for
这是真正的关键和任何工作

1371
01:05:22,852 --> 01:05:23,718
your homework by the way,
顺便说一下,你的家庭作业

1372
01:05:23,787 --> 01:05:28,990
really this homework it's not a lot of programming,
真的这作业不是很多编程,

1373
01:05:29,059 --> 01:05:30,792
It's a lot of thinking,
这是一个很多思考,

1374
01:05:30,860 --> 01:05:33,294
Especially designing your schema so
特别是设计模式

1375
01:05:33,362 --> 01:05:38,065
that this line of code right here is really simple,
这行代码是很简单的,

1376
01:05:38,134 --> 01:05:39,600
If you design your schema properly you can make
如果你正确你可以设计你的模式

1377
01:05:39,669 --> 01:05:40,501
this quite simple,
这很简单,

1378
01:05:40,570 --> 01:05:43,838
It's all about thinking about what am I actually showing,
其实都是想我展示,

1379
01:05:43,906 --> 01:05:46,307
and how do I calculate what those things are,
和我如何计算这些东西是什么,

1380
01:05:46,376 --> 01:05:49,377
In this case I'm showing all the Twitter users,
在这种情况下我给所有的Twitter用户,

1381
01:05:50,547 --> 01:05:57,718
Any of the twitter users here whose tweets,
这里的twitter用户的微博,

1382
01:05:57,787 --> 01:06:01,456
the text in their tweets actually, contains, and
文本在他们的微博,包含,

1383
01:06:01,525 --> 01:06:05,126
we'll go case insensitively, that search term,
我们将区分大小写,搜索词,

1384
01:06:05,195 --> 01:06:06,494
Our mention,
我们提到,

1385
01:06:06,563 --> 01:06:08,662
Which is optional, so we'd better unwrap,
这是可选的,所以我们最好打开,

1386
01:06:08,731 --> 01:06:11,398
And if I'm gonna unwrap this forcibly,
如果我要强行打开,

1387
01:06:11,467 --> 01:06:14,402
I'm actually going to check to make sure it's not nil,
我要检查,以确保它不是零,

1388
01:06:16,572 --> 01:06:18,940
Just to be careful there,
只是要小心,

1389
01:06:20,343 --> 01:06:21,875
So this is the predicate we want,
这是我们想要的谓词,

1390
01:06:21,944 --> 01:06:24,612
We want any Twitter user,
我们希望任何Twitter用户,

1391
01:06:24,681 --> 01:06:26,014
Because we're looking for Twitter users,
因为我们正在寻找Twitter用户,

1392
01:06:26,082 --> 01:06:29,617
any Twitter user who's tweets, any of their tweets,
任何Twitter用户的微博,他们的微博,

1393
01:06:29,686 --> 01:06:34,956
texts contains this mention,
文本包含这个提到,

1394
01:06:35,025 --> 01:06:35,590
This is actually,
这是,

1395
01:06:35,659 --> 01:06:38,292
I probably said that a little bit wrong there,
我可能说错了,一点

1396
01:06:38,361 --> 01:06:40,895
We're looking for any Twitter user who have any
我们正在寻找任何有Twitter用户

1397
01:06:40,964 --> 01:06:44,932
of it's tweets text contains this mention,
推文的文本包含这个提到,

1398
01:06:45,001 --> 01:06:48,035
Off of any, means here, anything, any of the tweets
的,意味着在这里,任何东西,任何的tweet

1399
01:06:48,104 --> 01:06:53,541
texts contains this, then show this twitter user here,
文本包含这个,那么显示这里的twitter用户,

1400
01:06:55,478 --> 01:06:56,877
Everybody got all that?
每个人都有吗?

1401
01:06:56,946 --> 01:07:00,014
So now, I got my fetch request controller,
所以现在,我取回请求控制器,

1402
01:07:00,082 --> 01:07:02,683
remember the only two things I need to do now is to
记得唯一我现在需要做的是两件事

1403
01:07:02,752 --> 01:07:07,221
try to have my fetched results controller perform this fetch,
试图让我获取结果控制器执行此取回,

1404
01:07:07,290 --> 01:07:10,324
okay that can throw, so that's why we're trying there,
能把好了,这就是为什么我们正在那里,

1405
01:07:10,393 --> 01:07:12,927
And we've got to tell our table view, time to go
我们要告诉我们的表视图,时间去

1406
01:07:12,995 --> 01:07:16,130
call all of your UI table view data source methods, and
叫你所有的UI数据源表视图方法,和

1407
01:07:16,199 --> 01:07:17,799
we know whose going to answer that,
我们知道,要回答这个问题,

1408
01:07:17,867 --> 01:07:20,201
that extension that we have there,
我们有,扩展,

1409
01:07:20,270 --> 01:07:22,436
And it's going to ask fetched results controller for
这是要问控制器获取结果

1410
01:07:22,505 --> 01:07:23,838
all the information it needs,
所需的所有信息,

1411
01:07:27,643 --> 01:07:33,014
By the way, notice I made this public, (internal, basically),
顺便说一下,请注意我做了这个,(内部,基本上),

1412
01:07:33,082 --> 01:07:36,784
That's because I put that extension over here
那是因为我把它扩展

1413
01:07:36,853 --> 01:07:38,119
in a different file and
在一个不同的文件

1414
01:07:38,188 --> 01:07:40,755
it wouldn't be a receive this otherwise,
它不会收到这否则,

1415
01:07:40,824 --> 01:07:43,691
So, if you wanna make this var private,
所以,如果你想让这个var私人,

1416
01:07:43,759 --> 01:07:46,094
which is not a bad idea, actually,
这不是一个坏主意,实际上,

1417
01:07:46,162 --> 01:07:48,762
In a MVC that is using a fetchedResultsController,
使用,fetchedResultsController MVC中,

1418
01:07:48,831 --> 01:07:51,365
making its controller public is kinda opening up
使其控制器公众开放

1419
01:07:51,434 --> 01:07:52,400
the internal guts of it,
它的内部结构,

1420
01:07:52,468 --> 01:07:55,703
If you wanna make this private, then you would just
如果你想让这个私人的,那么你就会

1421
01:07:55,772 --> 01:07:57,605
put this extension at the bottom of the file,
把这个扩展在文件的底部,

1422
01:07:57,674 --> 01:07:58,272
in the same file,
在相同的文件,

1423
01:07:58,341 --> 01:08:00,875
That way they you would be able to see it,
这样你能看到它,

1424
01:08:02,945 --> 01:08:10,718
Hopefully we've remembered everything,
希望我们记得一切,

1425
01:08:10,787 --> 01:08:15,523
let's go give this a try,
让我们去做这个实验,

1426
01:08:16,526 --> 01:08:18,393
Let's go here #stanford again,
让我们再#斯坦福大学,

1427
01:08:19,896 --> 01:08:21,429
Now I'm gonna press Tweeters,
现在我要按推特,

1428
01:08:21,497 --> 01:08:24,399
And it's going to segue to this new MVC that
它将继续这个新MVC

1429
01:08:24,467 --> 01:08:26,934
will hopefully show us a list of all the people who
希望给我们所有的人的列表吗

1430
01:08:27,003 --> 01:08:27,802
have tweeted here,
这里有推特,

1431
01:08:27,871 --> 01:08:29,069
And sure enough, there it is,
果然,就在那里。

1432
01:08:29,138 --> 01:08:31,706
These are all the people who have tweeted one of
这些都是推的人之一

1433
01:08:31,775 --> 01:08:33,975
the tweets that was found by that search team,
搜索团队的微博发现,

1434
01:08:34,043 --> 01:08:35,310
Search term #stanford,
搜索词#斯坦福大学,

1435
01:08:35,378 --> 01:08:37,411
It even has that listed at the top, which is kinda cool,
它甚至有上市顶部,有点酷,

1436
01:08:37,480 --> 01:08:40,914
because that's the same as the back button here,
因为这是一样的后退按钮,

1437
01:08:40,983 --> 01:08:42,850
Now, one thing I don't like about this,
现在,有一件事我不喜欢,

1438
01:08:42,918 --> 01:08:45,786
a couple of things, one, subtitle,
几件事情,1、副标题,

1439
01:08:45,855 --> 01:08:46,821
Okay that's no good,
好,不好,

1440
01:08:46,890 --> 01:08:48,423
we could put something better there like,
我们可以把更好的东西,

1441
01:08:48,491 --> 01:08:51,659
maybe we could put how many tweets they've tweeted
也许我们可以把多少推他们推

1442
01:08:51,727 --> 01:08:53,561
that match that search term, that'd be cool,
搜索词的匹配,会很酷,

1443
01:08:53,630 --> 01:08:55,763
And then, the other thing is the order its in,
然后,另一件事是订单,

1444
01:08:55,832 --> 01:08:59,100
look at this, all the capital letter's first and
看看这个,所有的大写字母的第一个

1445
01:08:59,169 --> 01:09:03,004
then all the lowercase letters after it,
之后所有的小写字母,

1446
01:09:03,072 --> 01:09:04,505
I want it all to be alphabetical case insensitive,
我想要所有的字母不区分大小写,

1447
01:09:04,506 --> 01:09:05,939
And like that,
像这样,

1448
01:09:06,008 --> 01:09:08,576
so let's fix those things,
所以让我们解决这些事情,

1449
01:09:08,645 --> 01:09:12,212
So the case insensitive is just a matter of sorting,
因此,不分大小写只是一个排序的问题,

1450
01:09:12,281 --> 01:09:14,349
We're sorting there and it's sorting by some default,
我们整理的一些默认的排序,

1451
01:09:14,417 --> 01:09:17,084
while the default is obviously case sensitive search and
在默认搜索,显然是大小写敏感的

1452
01:09:17,153 --> 01:09:18,185
we don't want that,
我们不希望这样,

1453
01:09:18,254 --> 01:09:21,155
So, this is where this sorting selector comes in,
所以,这就是这个排序选择器,

1454
01:09:21,223 --> 01:09:25,326
And we just say #selector and it's gotta be an NSString
我们只是说#选择器要NSString

1455
01:09:25,394 --> 01:09:27,628
selector because this is an NSString field,
选择器,因为这是一个NSString领域,

1456
01:09:27,697 --> 01:09:29,063
And there's quite a few of them,
还有很多,

1457
01:09:29,132 --> 01:09:32,733
if you type compare, you'll get to see what they are,
如果你类型比较,你就会看到它们是什么,

1458
01:09:32,802 --> 01:09:35,603
So, there's a localizedCaseInsensitive,
所以,有一个localizedCaseInsensitive,

1459
01:09:35,671 --> 01:09:38,973
this kind of thing, so, let's try CaseInsensitive,
这种事情,所以,让我们尝试CaseInsensitive,

1460
01:09:39,041 --> 01:09:41,675
Let's do localized case insensitive compare,
让我们做本地化不分大小写比较,

1461
01:09:41,744 --> 01:09:44,812
So that's case insensitive, and using the user's local
这是不分大小写,并使用用户的地方

1462
01:09:44,881 --> 01:09:48,783
language to know what goes where, what the ordering is,
语言知道了,定是什么,

1463
01:09:48,852 --> 01:09:49,884
So that's a pretty good one,
这是一个很好的一个,

1464
01:09:49,953 --> 01:09:52,420
to use localized case insensitive compare,
使用局部不分大小写比较,

1465
01:09:52,489 --> 01:09:54,956
So that's all we need to do to the case sensitivity,
这就是我们要做的大小写敏感性,

1466
01:09:55,024 --> 01:09:56,824
that was really easy,
这真的很容易,

1467
01:09:56,893 --> 01:10:01,496
How about this thing of having the cells detail text label?
这事怎么样的细胞详细文本标签吗?

1468
01:10:03,032 --> 01:10:05,065
Have the twitter account,
twitter帐户,

1469
01:10:05,134 --> 01:10:06,034
basically the account of tweet,
基本上twitter的帐户,

1470
01:10:06,102 --> 01:10:13,407
So I'm gonna say this equals twitter tweet count,
所以我会说,这等于twitter微博数,

1471
01:10:13,476 --> 01:10:18,980
Tweet and let's even be nice here and put an s if it's one,
微博让我们即使在这里很好,把一个年代如果是一个,

1472
01:10:20,483 --> 01:10:23,250
Count equals one,
数等于1,

1473
01:10:23,319 --> 01:10:27,654
Then we'll put an s on the end otherwise we're nothing,
然后我们会把一个年代的结束,否则我们什么都没有,

1474
01:10:27,723 --> 01:10:28,622
Okay, every one see what I did there?
好的,每一个看到我做了什么?

1475
01:10:28,691 --> 01:10:29,690
So it will take one tweet,
所以需要一个微博,

1476
01:10:29,759 --> 01:10:32,059
What else do we need to do here?
我们还需要做什么吗?

1477
01:10:32,128 --> 01:10:38,732
We'll do this,
我们会这样做,

1478
01:10:38,801 --> 01:10:40,001
All right, so I just want to make it look nice,
好吧,我只是想让它看起来不错,

1479
01:10:40,069 --> 01:10:42,804
One tweet, two tweets, zero tweets,
一个微博,两个微博,微博,零

1480
01:10:42,872 --> 01:10:44,738
How do I get this tweet count right here and
我怎么得到这个tweet计数和

1481
01:10:44,807 --> 01:10:47,742
let tweet count equal something?
让微博数等于什么?

1482
01:10:49,512 --> 01:10:53,580
And to do this, I'm going to do a little quick
要做到这一点,我要做的有点快

1483
01:10:53,649 --> 01:10:57,518
fast type code, because we're getting close to the end here,
快速类型代码,因为我们这里接近结束时,

1484
01:10:57,587 --> 01:11:00,588
I have a method here called tweet count,
我在这里有一个方法叫做微博数,

1485
01:11:00,657 --> 01:11:03,691
with mention by right here,
提到的在这里,

1486
01:11:03,760 --> 01:11:05,660
And let's look at this method and how this works,
让我们看看这个方法,这是如何工作的,

1487
01:11:05,728 --> 01:11:12,133
So this is gonna give the tweetCountWithMentionBy
这是要给tweetCountWithMentionBy

1488
01:11:12,201 --> 01:11:15,603
this twitterUser, the twitterUser that we got from
我们从这个twitterUser twitterUser

1489
01:11:15,672 --> 01:11:16,671
our fetchResultsController,
我们的fetchResultsController,

1490
01:11:16,739 --> 01:11:17,739
It's gonna give us the tweetCount,
它会给我们tweetCount,

1491
01:11:17,807 --> 01:11:20,541
And the way it's work is it's gonna create a fetch
和它的工作是要创建一个取回

1492
01:11:20,609 --> 01:11:21,408
for tweet,
微博,

1493
01:11:21,477 --> 01:11:25,880
So here even in the middle of my cellForRowAtIndexPath,
这甚至在半夜我cellForRowAtIndexPath,

1494
01:11:25,949 --> 01:11:29,083
I'm making a request perfectly valid to go to a fetch
我正在做一个请求完全有效去取回

1495
01:11:29,152 --> 01:11:31,285
request right in the middle here to find some information,
请求在这里找到一些信息,

1496
01:11:31,354 --> 01:11:33,187
So here I'm fetching for Tweets this time,
这里我抓取微博这一次,

1497
01:11:33,256 --> 01:11:36,557
cause I wanna count the number of Tweets this Twitter user
因为我想数一数这个Twitter用户的tweet

1498
01:11:36,626 --> 01:11:37,725
has Tweeted with that so sure,
推了,那么肯定,

1499
01:11:37,793 --> 01:11:39,126
And the predicate is,
谓词是,

1500
01:11:39,195 --> 01:11:44,398
"tell me all the Tweets who's text contains that mention",
“告诉我所有的消息文本包含提及是谁”,

1501
01:11:44,467 --> 01:11:47,335
And who's Tweeter is this Twitter user?
和推特这是Twitter用户是谁?

1502
01:11:50,606 --> 01:11:51,673
Mention and a twitterUser,
提到twitterUser,

1503
01:11:51,741 --> 01:11:54,241
And I'm gonna go ahead and force unwrap that,
我要和力打开,

1504
01:11:54,310 --> 01:11:56,577
because, boy if I get all the way down to here,
因为,男孩如果我一直到在这里,

1505
01:11:56,646 --> 01:11:58,246
surely the mention is not nil,
当然提到不是零,

1506
01:11:59,282 --> 01:12:01,015
And then I'm going to return,
然后我要返回,

1507
01:12:01,083 --> 01:12:04,351
I'm going to use the same context the twitterUser is in,
我将使用相同的上下文twitterUser在,

1508
01:12:04,420 --> 01:12:06,920
hopefully that's a view context,
希望这是一个视图上下文,

1509
01:12:06,989 --> 01:12:10,224
And I'm going to count, use that count thing for
我要统计,使用计数的事情

1510
01:12:10,293 --> 01:12:11,559
that request,
请求,

1511
01:12:11,627 --> 01:12:12,993
And if that fails for some reason,
如果由于某种原因失败时,

1512
01:12:13,062 --> 01:12:14,896
I'm gonna say 0 tweets,
我会说0条,

1513
01:12:17,000 --> 01:12:18,733
Have you got that?
你明白我的意思吗?

1514
01:12:18,802 --> 01:12:23,671
So let's go
所以让我们去

1515
01:12:23,740 --> 01:12:29,076
take a look,
看一看,

1516
01:12:29,145 --> 01:12:32,513
Right, #stanford,
#斯坦福大学,

1517
01:12:32,582 --> 01:12:33,681
Right, here it is,
在这里,

1518
01:12:33,750 --> 01:12:38,419
Tweeters, look at that, not 1 tweet, 37 tweets from MEC30,
高音,你看那个,不是1条推特,从MEC30 37 tweet,

1519
01:12:38,488 --> 01:12:41,021
Let's go see if we can find MEC30 in here,
让我们去看看我们是否能找到MEC30在这里,

1520
01:12:41,090 --> 01:12:43,824
Sure, there's one my MEC30, another one, sure enough,
当然,有一个我MEC30,另一个,果然,

1521
01:12:43,893 --> 01:12:45,392
Look at this ME, what the?
看这我,什么?

1522
01:12:45,461 --> 01:12:49,530
Okay, what if I decide I don't want MEC30 in there anymore,
好吧,如果我决定我不想MEC30在那里了,

1523
01:12:49,598 --> 01:12:51,999
I don't like, this guy is a spammer or something,
我不喜欢,这个人是一个垃圾邮件发送者,

1524
01:12:52,067 --> 01:12:53,534
I don't know what his problem is,
我不知道他的问题是什么,

1525
01:12:53,603 --> 01:12:54,868
But I don't want him in there,
但我不希望他在那里,

1526
01:12:54,937 --> 01:12:58,706
Well, I can go back here and change my predicate right here
好了,我可以回到这里,改变我的谓词

1527
01:12:58,774 --> 01:13:02,309
to say, I want all the tweets that have that,
说,我想要的所有微博,

1528
01:13:02,378 --> 01:13:07,881
But I don't want ones where the handle of that guy, let's
但我不希望处理的那个家伙,我们

1529
01:13:07,950 --> 01:13:13,454
say it even begins with, just to be kind of interesting MEC,
说它甚至开始,就有点有趣的MEC,

1530
01:13:13,523 --> 01:13:14,055
What was it?
是什么?

1531
01:13:14,123 --> 01:13:16,156
MEC, we'll say,
MEC,我们会说,

1532
01:13:16,225 --> 01:13:20,260
And we can't put this literal in here, so
我们不能把这个文字在这里,

1533
01:13:20,329 --> 01:13:26,534
we have to say %@ and then we put the MEC on the outside,
我们不得不说% @然后我们把MEC在外面,

1534
01:13:26,603 --> 01:13:31,205
So let's see
让我们看看

1535
01:13:31,273 --> 01:13:36,277
if that got rid
如果去掉

1536
01:13:36,346 --> 01:13:40,981
of Mr, MEC,
MEC先生,

1537
01:13:41,050 --> 01:13:44,418
He gone!
他不见了!

1538
01:13:44,487 --> 01:13:46,653
Got that spammer out of there,
明白了垃圾信息散布者,

1539
01:13:46,722 --> 01:13:47,254
No questions?
没有问题吗?

1540
01:13:47,323 --> 01:13:48,489
Yes? Question?
是吗?

1541
01:13:48,558 --> 01:13:51,191
Yeah, so the question is, are the tweets in the database,
是的,问题是,数据库中的信息,

1542
01:13:51,260 --> 01:13:53,861
do they stay in there for run to run?
他们呆在那里跑,跑吗?

1543
01:13:53,930 --> 01:13:55,262
And the answer is absolutely,
答案是绝对的,

1544
01:13:55,331 --> 01:13:57,264
that's one, core data is kinda all about,
这是一个核心数据是有点,

1545
01:13:57,333 --> 01:13:58,432
There's a permanent database,
有一个永久的数据库,

1546
01:13:58,501 --> 01:14:01,535
So all those tweets, those #stanford tweets in there,
所以所有这些推文,那些#斯坦福微博,

1547
01:14:01,604 --> 01:14:03,137
if we go back and run again,
如果我们回去再次运行,

1548
01:14:08,611 --> 01:14:10,244
And search for #stanford,
和搜索#斯坦福大学,

1549
01:14:10,313 --> 01:14:11,712
If there have, you know,
如果有,你知道,

1550
01:14:11,780 --> 01:14:14,148
been some tweets since then they'll be added,
一些twitter之后他们会被添加,

1551
01:14:14,217 --> 01:14:16,717
But every single tweet we ever got is still
但每一个微博我们仍了

1552
01:14:16,786 --> 01:14:17,517
going to be in here,
在这里,

1553
01:14:17,586 --> 01:14:19,453
So you can see this list actually got slightly longer,
所以你可以看到这个列表实际上有稍微长一点,

1554
01:14:19,522 --> 01:14:21,388
a few tweets were in there, but they're all in there,
几个微博都在那里,但他们都在那里呢,

1555
01:14:21,457 --> 01:14:26,159
we're unique-ing them so it's not adding them over and over,
我们unique-ing他们这不是增加他们一遍又一遍,

1556
01:14:26,228 --> 01:14:27,761
And you gotta be careful to do that on your homework,
你要小心地做你的家庭作业,

1557
01:14:27,830 --> 01:14:29,630
Don't add them over and over,
不要把它们一遍又一遍,

1558
01:14:29,699 --> 01:14:31,632
But yeah, that CoreData database is there,
但是是的,CoreData数据库,

1559
01:14:31,701 --> 01:14:33,467
By the way, I'm gonna show you a trick,
顺便说一下,我要告诉你一个窍门,

1560
01:14:33,535 --> 01:14:35,569
We just enough time to show you something's really cool,
我们只是足够的时间向你展示一些很酷,

1561
01:14:35,638 --> 01:14:38,472
What if you want to delete your database?
如果你想删除数据库呢?

1562
01:14:38,541 --> 01:14:40,507
Okay, now there's two reasons you wanna,
好了,现在有两个原因你想,

1563
01:14:40,576 --> 01:14:41,641
might wanna delete your database,
可能想删除数据库,

1564
01:14:41,710 --> 01:14:43,844
One, you wanna clear the data out cuz you wanna get a fresh
一个,你想要清除数据因为你想要一个新鲜

1565
01:14:43,913 --> 01:14:45,880
set so you can see if things are working,
所以你可以看到如果事情工作,

1566
01:14:45,948 --> 01:14:49,416
And number two, you might change your data model,
第二,你可能会改变你的数据模型,

1567
01:14:49,485 --> 01:14:53,453
If I go back here and I go to my data model here and
如果我回到这里,我去和我的数据模型

1568
01:14:53,522 --> 01:14:56,323
I add some attributes or add an entity,
我添加一些属性或添加一个实体,

1569
01:14:56,392 --> 01:15:01,628
then my app will no longer run on that device or
然后我的设备或应用程序将不再运行

1570
01:15:01,697 --> 01:15:05,833
on the simulator cuz it'll say your data model doesn't match
模拟器上因为它会说你的数据模型不匹配

1571
01:15:05,902 --> 01:15:07,902
the data that's already on this device,
已经在这个设备的数据,

1572
01:15:07,970 --> 01:15:10,938
So here's the magic to get rid of, it's not very magical,
这是魔法摆脱,它不是很神奇,

1573
01:15:11,006 --> 01:15:12,206
Is on your device, or
在你的设备上,还是

1574
01:15:12,275 --> 01:15:15,543
on the simulator, you go to the home button right here and
模拟器,按钮在这里和你去家里

1575
01:15:15,612 --> 01:15:19,413
you press and hold to make the things jiggle,
你按住摇晃的东西,

1576
01:15:19,482 --> 01:15:20,280
You all know about that?
你们都知道吗?

1577
01:15:20,349 --> 01:15:21,648
It's how you delete apps,
这是你如何删除应用程序,

1578
01:15:21,717 --> 01:15:25,018
And just delete your app,
删除你的应用,

1579
01:15:25,087 --> 01:15:28,755
And when you delete your app, your core data goes with it,
当你删除你的应用,你的核心数据,

1580
01:15:28,824 --> 01:15:31,491
And now when you run the next time, you're gonna run,
现在,当您运行下次,你要跑,

1581
01:15:31,560 --> 01:15:33,160
it's gonna be a fresh database,
它会是一个新的数据库,

1582
01:15:33,229 --> 01:15:34,961
it will have the new data model etc,
它将有新的数据模型等,

1583
01:15:35,030 --> 01:15:36,664
So I'm very glad you asked that,
我很高兴你问,

1584
01:15:36,732 --> 01:15:39,599
really important to know how to clear out your database,
真正重要的知道如何清理你的数据库,

1585
01:15:39,668 --> 01:15:43,070
Now if we do #trump or something,
如果我们做#特朗普,

1586
01:15:43,138 --> 01:15:48,342
see it's even asking me again, do I wanna allow it?
再次见到甚至问我,我想让它吗?

1587
01:15:48,410 --> 01:15:49,143
And I do,
我做的,

1588
01:15:53,582 --> 01:15:55,449
All right, that is it,
好吧,就是这样,

1589
01:15:55,518 --> 01:15:58,319
I will see you next Wednesday after you turn in your
下周三我将见到你在你在你转

1590
01:15:58,388 --> 01:15:59,252
homework and
作业,

1591
01:15:59,321 --> 01:16:04,691
we'll learn all about the final project in Autolayout,
我们将学习所有关于自动布局,最终项目的

1592
01:16:04,760 --> 01:16:14,768
For more, please visit us at stanford,edu,
更多信息,请访问我们的斯坦福大学edu,