Merge pull request #51 from yanqizhao/feature/lecture_2_151-200

翻译第 2 集 151 - 200 条字幕

Author: LiulietLee

subtitles/en/Lecture 2. MVVM and the Swift Type System.srt

@@ -835,7 +835,7 @@ between the Model and the View.
 
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-It's gonna be the thing that
+It's going be the thing that
 
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subtitles/zh-Hans/Lecture 2. MVVM and the Swift Type System.srt

@@ -621,224 +621,207 @@ Text 和 HStack
 
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-At any time you should be able to say
+任何时刻你都可以让视图
 
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-make it look like the Model
+按照模型中的数据来显示
 
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-and so, we are gonna have a system
+在 Swift 中有一种机制
 
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-where whenever the Model changes,
+可以在模型发生变化时
 
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-it asks the View to look
-like it automatically.
+自动更新视图
 
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-Call that reactive programming,
+叫做响应式编程
 
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-it's reacting to changes in the Model.
+它会对模型中的变化作出响应
 
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-So that's it.
+就是这样一种机制
 
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-This is what we got to make happen
+我们引入视图模型（ViewModel）
 
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-is it introduces another
-thing called the ViewModel.
+来实现这种机制
 
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-The ViewModel's job is to
-bind the View to the Model.
+视图模型的工作就是将视图
+绑定到对应的模型上
 
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-So the one change has
-happened in the Model,
+模型中的数据一旦发生变化
 
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-the View get reflected.
+视图就会对其作出响应
 
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-And along the way,
+在视图模型
 
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-as it does that binding
-between the Model and the View,
+对模型和视图进行绑定的过程中
 
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-it might be interpreting
-the Model for the View
+会将模型中的数据转换为
+视图可以理解的形式
 
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-because we want the View to be very simple
+因为我们希望在声明式编程中
 
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-since we're writing it
-in a declarative way,
+视图能够尽量简洁
 
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-we don't want it to have
-a lot of code in there
+我们不希望视图中的代码过多
 
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-that's like converting from
-one data type to another
+例如数据类型转换之类的工作
 
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-and things like that.
+都不要交给视图
 
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-So we're gonna ask the
-ViewModel to do that.
+而是交给视图模型去做
 
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-Our Model in our game
-that we're writing here,
+我们这里构建的记忆游戏中的模型
 
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-this memory game, our Model
-is just gonna be a struct.
+是一个结构体
 
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-This is a very simple little demo
+这是一个非常简单的示例程序
 
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-but you could imagine that your Model
+但是你可以设想这里的模型
 
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-is a SQL database or it's
-something over the network
+是一个 SQL 数据库，或是向网络发出的
 
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-where you're making HTTP requests.
+HTTP 请求
 
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-So it can be quite complicated over there
+这样的模型就相当复杂了
 
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-and your ViewModel can simplify that,
+视图模型可以将其封装到
 
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-boil it down into maybe
-some simpler data structures
+更简洁的数据结构中
 
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-that it can pass to the View
+之后再传递给视图
 
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-that will let the View be
-simple code that draws it.
+这样视图中就只有实现绘制的代码了
 
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-So, the ViewModel does
-have this role a little bit
+视图模型在这里扮演的角色
 
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-as an interpreter of that Model data.
+就像一个模型数据的解释者
 
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-So we're gonna interpose the ViewModel
+这样我们就引入了介于模型和视图
 
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-between the Model and the View.
+之间的视图模型
 
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-It's gonna be the thing that
+它帮助视图实现
 
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-helps make this automatic
-updating happening.
+自动更新
 
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-So how does it do what it does?
+那么它是如何做到的呢？
 
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-Well, first of all the ViewModel
+首先，视图模型
 
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-is always trying to notice
-changes in the Model
+会随时关注模型的变化
 
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-and it can do that any way that it wants.
+它可以通过任何方式实现
 
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-If your Model is a struct,
-it's actually quite easy.
+如果你的模型是一个结构体
+那相当容易
 
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-Again, I'm gonna talk about a struct,
+我又一次谈到了结构体
 
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-more about that type in
-Swift in a few moments
+之后还会讲到更多关于 Swift 中
+结构体这个类型的特性
 
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-but one great feature of a struct
+其中一个重要的特性是
 
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-since it's copied around
+因为将结构体
 
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-when it's passed to functions and stuff
+传递给函数时会被复制一份
 
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-is that Swift knows when
-a struct has changed.
+所以 Swift 知道结构体发生变化的时机
 
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