RxAndroid 的使用方式

本文主要是介绍RxAndroid 的使用方式，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

RxAndroid是RxJava的扩展, 优雅地处理异步请求. RxAndroid配合Lambda表达式, 精简处理回调, 使程序更具有可读性. Rx作为Android最优秀的开源库之一, 极大地提高生产力, 我们需要掌握. 本文由浅入深, 介绍一些常见的使用方法, 并附有源码.

更多: http://www.wangchenlong.org/

本文代码的GitHub下载地址.

要点包含:
(1) 链式表达式的使用方式.
(2) Lambda的应用.
(3) Rx处理网络请求.
(4) 线程自动管理, 防止内存泄露.
(5) RxBinding绑定控件的异步事件.

基础

当然, 从一个崭新的HelloWorld项目开始.

添加Gradle配置.

 
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 compile   'com.jakewharton:butterknife:7.0.1' 
 compile   'io.reactivex:rxandroid:1.1.0'   // RxAndroid 
 compile   'io.reactivex:rxjava:1.1.0'   // 推荐同时加载RxJava

RxAndroid是本文的核心依赖, 同时添加RxJava. 还有ButterKnife注解库.

Lambda表达式, 是写出优雅代码的关键, 参考.

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 plugins   { 
      id   "me.tatarka.retrolambda"   version   "3.2.4" 
 } 
 android   { 
  . . . 
      compileOptions   { 
          sourceCompatibility  JavaVersion . VERSION_1_8 
          targetCompatibility  JavaVersion . VERSION_1 _8 
      } 
 } 
 

Gradle 2.1+以上, 配置非常简单, 添加一个plugin和一个Java1.8兼容即可.

从主MainActivity跳转至SimpleActivity.

 
 
 
 
 
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 /** 
  * 主Activity, 用于跳转各个模块. 
  * 
  * @author wangchenlong 
  */ 
 public   class   MainActivity   extends   AppCompatActivity   { 
      @Override 
      protected   void   onCreate ( Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_main ) ; 
      } 
      // 跳转简单的页面 
      public   void   gotoSimpleModule ( View  view )   { 
          startActivity ( new   Intent ( this ,   SimpleActivity . class ) ) ; 
      } 
      // 跳转复杂的页面 
      public   void   gotoMoreModule ( View  view )   { 
          startActivity ( new   Intent ( this ,   MoreActivity . class ) ) ; 
      } 
      // 跳转Lambda的页面 
      public   void   gotoLambdaModule ( View  view )   { 
          startActivity ( new   Intent ( this ,   LambdaActivity . class ) ) ; 
      } 
      // 跳转网络的页面 
      public   void   gotoNetworkModule ( View  view )   { 
          startActivity ( new   Intent ( this ,   NetworkActivity . class ) ) ; 
      } 
      // 跳转线程安全的页面 
      public   void   gotoSafeModule ( View  view )   { 
          startActivity ( new   Intent ( this ,   SafeActivity . class ) ) ; 
      } 
 } 
 

在SimpleActivity中, 创建一个观察者, 收到字符串的返回.

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 // 观察事件发生 
      Observable . OnSubscribe  mObservableAction   =   new   Observable . OnSubscribe <String> ( )   { 
          @Override   public   void   call ( Subscriber < ?   super   String >   subscriber )   { 
              subscriber . onNext ( sayMyName ( ) ) ;   // 发送事件 
              subscriber . onCompleted ( ) ;   // 完成事件 
          } 
      } ; 
 . . . 
      // 创建字符串 
      private   String   sayMyName ( )   { 
          return   "Hello, I am your friend, Spike!" ; 
      } 
 

创建两个订阅者, 使用字符串输出信息.

 
 
 
 
 
 
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 // 订阅者, 接收字符串, 修改控件 
 Subscriber <String>   mTextSubscriber   =   new   Subscriber <String> ( )   { 
      @Override   public   void   onCompleted ( )   { 
      } 
      @Override   public   void   onError ( Throwable   e )   { 
      } 
      @Override   public   void   onNext ( String   s )   { 
          mTvText . setText ( s ) ;   // 设置文字 
      } 
 } ; 
 // 订阅者, 接收字符串, 提示信息 
 Subscriber <String>   mToastSubscriber   =   new   Subscriber <String> ( )   { 
      @Override   public   void   onCompleted ( )   { 
      } 
      @Override   public   void   onError ( Throwable   e )   { 
      } 
      @Override   public   void   onNext ( String   s )   { 
          Toast . makeText ( SimpleActivity . this ,   s ,   Toast . LENGTH_SHORT ) . show ( ) ; 
      } 
 } ; 
 

在页面中, 观察者接收信息, 发送至主线程AndroidSchedulers.mainThread(), 再传递给订阅者, 由订阅者最终处理消息. 接收信息可以是同步, 也可以是异步.

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 @Override   protected   void   onCreate ( Bundle  savedInstanceState )   { 
      super . onCreate ( savedInstanceState ) ; 
      setContentView ( R . layout . activity_simple ) ; 
      ButterKnife . bind ( this ) ; 
      // 注册观察活动 
      @SuppressWarnings ( "unchecked" ) 
      Observable <String>   observable   =   Observable . create ( mObservableAction ) ; 
      // 分发订阅信息 
      observable . observeOn ( AndroidSchedulers . mainThread ( ) ) ; 
      observable . subscribe ( mTextSubscriber ) ; 
      observable . subscribe ( mToastSubscriber ) ; 
 } 
 

最基础的RxAndroid使用.

我们已经熟悉了初步的使用方式, 在接着学习一些其他方法, 如

just: 获取输入数据, 直接分发, 更加简洁, 省略其他回调.
from: 获取输入数组, 转变单个元素分发.
map: 映射, 对输入数据进行转换, 如大写.
flatMap: 增大, 本意就是增肥, 把输入数组映射多个值, 依次分发.
reduce: 简化, 正好相反, 把多个数组的值, 组合成一个数据.

来看看这个示例, 设置两个不同类型数组, 作为输入源, 根据不同情况分发数据.

 
 
 
 
 
 
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 /** 
  * 更多的RxAndroid的使用方法. 
  * <p> 
  * Created by wangchenlong on 15/12/30. 
  */ 
 public   class   MoreActivity   extends   Activity   { 
      @Bind ( R . id . simple_tv_text )   TextView  mTvText ; 
      final   String [ ]   mManyWords   =   { "Hello" ,   "I" ,   "am" ,   "your" ,   "friend" ,   "Spike" } ; 
      final   List <String>   mManyWordList   =   Arrays . asList ( mManyWords ) ; 
      // Action类似订阅者, 设置TextView 
      private   Action1 <String>   mTextViewAction   =   new   Action1 <String> ( )   { 
          @Override   public   void   call ( String   s )   { 
              mTvText . setText ( s ) ; 
          } 
      } ; 
      // Action设置Toast 
      private   Action1 <String>   mToastAction   =   new   Action1 <String> ( )   { 
          @Override   public   void   call ( String   s )   { 
              Toast . makeText ( MoreActivity . this ,   s ,   Toast . LENGTH_SHORT ) . show ( ) ; 
          } 
      } ; 
      // 设置映射函数 
      private   Func1 < List <String> ,   Observable <String> >   mOneLetterFunc   =   new   Func1 < List <String> ,   Observable <String> > ( )   { 
          @Override   public   Observable <String>   call ( List <String>   strings )   { 
              return   Observable . from ( strings ) ;   // 映射字符串 
          } 
      } ; 
      // 设置大写字母 
      private   Func1 < String ,   String >   mUpperLetterFunc   =   new   Func1 < String ,   String > ( )   { 
          @Override   public   String   call ( String   s )   { 
              return   s . toUpperCase ( ) ;   // 大小字母 
          } 
      } ; 
      // 连接字符串 
      private   Func2 < String ,   String ,   String >   mMergeStringFunc   =   new   Func2 < String ,   String ,   String > ( )   { 
          @Override   public   String   call ( String   s ,   String   s2 )   { 
              return   String . format ( "%s %s" ,   s ,   s2 ) ;   // 空格连接字符串 
          } 
      } ; 
      @Override 
      protected   void   onCreate ( Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_simple ) ; 
          ButterKnife . bind ( this ) ; 
          // 添加字符串, 省略Action的其他方法, 只使用一个onNext. 
          Observable <String>   obShow   =   Observable . just ( sayMyName ( ) ) ; 
          // 先映射, 再设置TextView 
          obShow . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . map ( mUpperLetterFunc ) . subscribe ( mTextViewAction ) ; 
          // 单独显示数组中的每个元素 
          Observable <String>   obMap   =   Observable . from ( mManyWords ) ; 
          // 映射之后分发 
          obMap . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . map ( mUpperLetterFunc ) . subscribe ( mToastAction ) ; 
          // 优化过的代码, 直接获取数组, 再分发, 再合并, 再显示toast, Toast顺次执行. 
          Observable . just ( mManyWordList ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . flatMap ( mOneLetterFunc ) 
                  . reduce ( mMergeStringFunc ) 
                  . subscribe ( mToastAction ) ; 
      } 
      // 创建字符串 
      private   String   sayMyName ( )   { 
          return   "Hello, I am your friend, Spike!" ; 
      } 
 } 
 

这次简化调用代码, 因为有时候我们对异常并不是很关心,
只要能catch异常即可, 因此流仅仅关注真正需要的部分.

输入字符串, 变换大写, 输出至控件中显示.

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 // 添加字符串, 省略Action的其他方法, 只使用一个onNext. 
 Observable <String>   obShow   =   Observable . just ( sayMyName ( ) ) ; 
 // 先映射, 再设置TextView 
 obShow . observeOn ( AndroidSchedulers . mainThread ( ) ) 
          . map ( mUpperLetterFunc ) . subscribe ( mTextViewAction ) ; 
 

just可以非常简单的获取任何数据, 分发时, 选择使用的线程.
map是对输入数据加工, 转换类型, 输入Func1, 准换大写字母.
Func1代表使用一个参数的函数, 前面是参数, 后面是返回值.
Action1代表最终动作, 因而不需要返回值, 并且一个参数.

输入数组, 单独分发数组中每一个元素, 转换大写, 输入Toast连续显示.

 
 
 
 
 
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 // 单独显示数组中的每个元素 
 Observable <String>   obMap   =   Observable . from ( mManyWords ) ; 
 // 映射之后分发 
 obMap . observeOn ( AndroidSchedulers . mainThread ( ) ) 
          . map ( mUpperLetterFunc ) . subscribe ( mToastAction ) ; 
 

from是读取数组中的值, 每次单独分发, 并分发多次, 其余类似.

输入数组, 映射为单独分发, 并组合到一起, 集中显示.

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 // 优化过的代码, 直接获取数组, 再分发, 再合并, 再显示toast, Toast顺次执行. 
 Observable . just ( mManyWordList ) 
          . observeOn ( AndroidSchedulers . mainThread ( ) ) 
          . flatMap ( mOneLetterFunc ) 
          . reduce ( mMergeStringFunc ) 
          . subscribe ( mToastAction ) ; 
 

这次是使用just分发数组, 则分发数据就是数组, 并不是数组中的元素.
flatMap把数组转换为单独分发, Func1内部使用from拆分数组.
reduce把单独分发数据集中到一起, 再统一分发, 使用Func2.
最终使用Action1显示获得数据. 本次代码也更加简洁.

由此我们可以观察到, Rx的写法可以是多种多样, 合理的写法会更加优雅.

效果

Lambda

Lambda表达式和Rx非常契合, 可以省略大量的内部类, 如Func和Action.
我们把上个示例, 用Lambda再写一次, 功能相同.

 
 
 
 
 
 
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 /** 
  * Lambda表达式写法 
  * <p> 
  * Created by wangchenlong on 15/12/31. 
  */ 
 public   class   LambdaActivity   extends   Activity   { 
      @Bind ( R . id . simple_tv_text )   TextView  mTvText ; 
      final   String [ ]   mManyWords   =   { "Hello" ,   "I" ,   "am" ,   "your" ,   "friend" ,   "Spike" } ; 
      final   List <String>   mManyWordList   =   Arrays . asList ( mManyWords ) ; 
      @Override   protected   void   onCreate ( Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_simple ) ; 
          ButterKnife . bind ( this ) ; 
          // 添加字符串, 省略Action的其他方法, 只使用一个onNext. 
          Observable <String>   obShow   =   Observable . just ( sayMyName ( ) ) ; 
          // 先映射, 再设置TextView 
          obShow . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . map ( String :: toUpperCase ) . subscribe ( mTvText :: setText ) ; 
          // 单独显示数组中的每个元素 
          Observable <String>   obMap   =   Observable . from ( mManyWords ) ; 
          // 映射之后分发 
          obMap . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . map ( String :: toUpperCase ) 
                  . subscribe ( this :: showToast ) ; 
          // 优化过的代码, 直接获取数组, 再分发, 再合并, 再显示toast, Toast顺次执行. 
          Observable . just ( mManyWordList ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . flatMap ( Observable :: from ) 
                  . reduce ( this :: mergeString ) 
                  . subscribe ( this :: showToast ) ; 
      } 
      // 创建字符串 
      private   String   sayMyName ( )   { 
          return   "Hello, I am your friend, Spike!" ; 
      } 
      // 显示Toast 
      private   void   showToast ( String   s )   { 
          Toast . makeText ( LambdaActivity . this ,   s ,   Toast . LENGTH_SHORT ) . show ( ) ; 
      } 
      // 合并字符串 
      private   String   mergeString ( String   s1 ,   String   s2 )   { 
          return   String . format ( "%s %s" ,   s1 ,   s2 ) ; 
      } 
 } 
 

这次没有使用常规的Lambda表达式, 而是更简单的方法引用(Method References).
方法引用: 方法参数和返回值与Lambda表达式相同时, 使用方法名代替.

网络请求

Retrofit是网络请求库, 刚推出2.0版本. Rx的一个核心应用就是处理异步网络请求, 结合Retrofit, 会更加方便和简洁. 参考.

引入库

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 compile   'com.android.support:recyclerview-v7:23.1.1'   // RecyclerView 
 compile   'com.squareup.retrofit:retrofit:2.0.0-beta2'   // Retrofit网络处理 
 compile   'com.squareup.retrofit:adapter-rxjava:2.0.0-beta2'   // Retrofit的rx解析库 
 compile   'com.squareup.retrofit:converter-gson:2.0.0-beta2'   // Retrofit的gson库 
 compile   'com.squareup.picasso:picasso:2.5.2'   // Picasso网络图片加载 
 

recyclerview和picasso为了显示. retrofit系列是网络请求.

主页使用一个简单的列表视图, 展示Github的用户信息.

 
 
 
 
 
 
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 /** 
  * Rx的网络请求方式 
  * <p> 
  * Created by wangchenlong on 15/12/31. 
  */ 
 public   class   NetworkActivity   extends   Activity   { 
      @Bind ( R . id . network_rv_list )   RecyclerView  mRvList ;   // 列表 
      @Override   protected   void   onCreate ( Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_network ) ; 
          ButterKnife . bind ( this ) ; 
          // 设置Layout管理器 
          LinearLayoutManager  layoutManager   =   new   LinearLayoutManager ( this ) ; 
          layoutManager . setOrientation ( LinearLayoutManager . VERTICAL ) ; 
          mRvList . setLayoutManager ( layoutManager ) ; 
          // 设置适配器 
          UserListAdapter  adapter   =   new   UserListAdapter ( this :: gotoDetailPage ) ; 
          NetworkWrapper . getUsersInto ( adapter ) ; 
          mRvList . setAdapter ( adapter ) ; 
      } 
      // 点击的回调 
      public   interface   UserClickCallback   { 
          void   onItemClicked ( String   name ) ; 
      } 
      // 跳转到库详情页面 
      private   void   gotoDetailPage ( String   name )   { 
          startActivity ( NetworkDetailActivity . from ( NetworkActivity . this ,   name ) ) ; 
      } 
 } 
 

在列表中提供点击用户信息跳转至用户详情.
NetworkWrapper.getUsersInto(adapter) 请求网络, 设置适配器信息.

关键部分, 适配器, 其中包含ViewHolder类和数据类.

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 /** 
 * 显示列表 
 * <p> 
 * Created by wangchenlong on 15/12/31. 
 */ 
 public   class   UserListAdapter  extends   RecyclerView . Adapter < UserListAdapter . UserViewHolder >   { 
      private   List <GitHubUser>   mUsers ;   // 用户名集合 
      private   NetworkActivity . UserClickCallback  mCallback ;   // 用户点击项的回调 
      public   UserListAdapter ( NetworkActivity . UserClickCallback  callback )   { 
          mUsers   =   new   ArrayList <> ( ) ; 
          mCallback   =   callback ; 
      } 
      public   void   addUser ( GitHubUser  user )   { 
          mUsers . add ( user ) ; 
          notifyItemInserted ( mUsers . size ( )   -   1 ) ;   // 最后一位 
      } 
      @Override   public   UserViewHolder  onCreateViewHolder ( ViewGroup  parent ,   int   viewType )   { 
          View  item   =   LayoutInflater . from ( parent . getContext ( ) ) 
                  . inflate ( R . layout . item_network_user ,   parent ,   false ) ; 
          return   new   UserViewHolder ( item ,   mCallback ) ; 
      } 
      @Override   public   void   onBindViewHolder ( UserViewHolder  holder ,   int   position )   { 
          holder . bindTo ( mUsers . get ( position ) ) ; 
      } 
      @Override   public   int   getItemCount ( )   { 
          return   mUsers . size ( ) ; 
      } 
      // Adapter的ViewHolder 
      public   static   class   UserViewHolder  extends   RecyclerView . ViewHolder   { 
          @Bind ( R . id . network_item_iv_user_picture )   ImageView  mIvUserPicture ; 
          @Bind ( R . id . network_item_tv_user_name )   TextView  mTvUserName ; 
          @Bind ( R . id . network_item_tv_user_login )   TextView  mTvUserLogin ; 
          @Bind ( R . id . network_item_tv_user_page )   TextView  mTvUserPage ; 
          public   UserViewHolder ( View  itemView ,   NetworkActivity . UserClickCallback  callback )   { 
              super ( itemView ) ; 
              ButterKnife . bind ( this ,   itemView ) ; 
              // 绑定点击事件 
              itemView . setOnClickListener ( v   -> 
                      callback . onItemClicked ( mTvUserLogin . getText ( ) . toString ( ) ) ) ; 
          } 
          // 绑定数据 
          public   void   bindTo ( GitHubUser  user )   { 
              mTvUserName . setText ( user . name ) ; 
              mTvUserLogin . setText ( user . login ) ; 
              mTvUserPage . setText ( user . repos_url ) ; 
              Picasso . with ( mIvUserPicture . getContext ( ) ) 
                      . load ( user . avatar_url ) 
                      . placeholder ( R . drawable . ic_person_black_24dp ) 
                      . into ( mIvUserPicture ) ; 
          } 
      } 
      // 用户类, 名称必须与Json解析相同 
      public   static   class   GitHubUser   { 
          public   String   login ; 
          public   String   avatar_url ; 
          public   String   name ; 
          public   String   repos_url ; 
      } 
 } 
 

添加数据addUser, 其中notifyItemInserted通知更新.
可以自动生成Json解析类的网站.

首先创建Retrofit`服务, 通过服务获取数据, 再依次分发给适配器.

 
 
 
 
 
 
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 /** 
  * 用户获取类 
  * <p> 
  * Created by wangchenlong on 15/12/31. 
  */ 
 public   class   NetworkWrapper   { 
      private   static   final   String [ ]   mFamousUsers   = 
              { "SpikeKing" ,   "JakeWharton" ,   "rock3r" ,   "Takhion" ,   "dextorer" ,   "Mariuxtheone" } ; 
      // 获取用户信息 
      public   static   void   getUsersInto ( final   UserListAdapter  adapter )   { 
          GitHubService  gitHubService   = 
                  ServiceFactory . createServiceFrom ( GitHubService . class ,   GitHubService . ENDPOINT ) ; 
          Observable . from ( mFamousUsers ) 
                  . flatMap ( gitHubService :: getUserData ) 
                  . subscribeOn ( Schedulers . newThread ( ) ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . subscribe ( adapter :: addUser ) ; 
      } 
      // 获取库信息 
      public   static   void   getReposInfo ( final   String   username ,   final   RepoListAdapter  adapter )   { 
          GitHubService  gitHubService   = 
                  ServiceFactory . createServiceFrom ( GitHubService . class ,   GitHubService . ENDPOINT ) ; 
          gitHubService . getRepoData ( username ) 
                  . flatMap ( Observable :: from ) 
                  . subscribeOn ( Schedulers . newThread ( ) ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . subscribe ( adapter :: addRepo ) ; 
      } 
 } 
 

网络请求无法在主线程上执行, 需要启动异步线程, 如Schedulers.newThread().
使用工厂模式ServiceFactory创建服务, 也可以单独创建服务.

创建Retrofit服务的工厂类.

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 /** 
 * 用户获取类 
 * <p> 
 * Created by wangchenlong on 15/12/31. 
 */ 
 public   class   NetworkWrapper   { 
      private   static   final   String [ ]   mFamousUsers   = 
              { "SpikeKing" ,   "JakeWharton" ,   "rock3r" ,   "Takhion" ,   "dextorer" ,   "Mariuxtheone" } ; 
      // 获取用户信息 
      public   static   void   getUsersInto ( final   UserListAdapter  adapter )   { 
          GitHubService  gitHubService   = 
                  ServiceFactory . createServiceFrom ( GitHubService . class ,   GitHubService . ENDPOINT ) ; 
          Observable . from ( mFamousUsers ) 
                  . flatMap ( gitHubService :: getUserData ) 
                  . subscribeOn ( Schedulers . newThread ( ) ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . subscribe ( adapter :: addUser ) ; 
      } 
      // 获取库信息 
      public   static   void   getReposInfo ( final   String   username ,   final   RepoListAdapter  adapter )   { 
          GitHubService  gitHubService   = 
                  ServiceFactory . createServiceFrom ( GitHubService . class ,   GitHubService . ENDPOINT ) ; 
          gitHubService . getRepoData ( username ) 
                  . flatMap ( Observable :: from ) 
                  . subscribeOn ( Schedulers . newThread ( ) ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . subscribe ( adapter :: addRepo ) ; 
      } 
 } 
 

这是Retrofit 2.0的写法, 注意需要添加Rx和Gson的解析.

设置网络请求的Url.

 
 
 
 
 
 
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 /** 
  * GitHub的服务 
  * <p> 
  * Created by wangchenlong on 15/12/31. 
  */ 
 public   interface   GitHubService   { 
      String   ENDPOINT   =   "https://api.github.com" ; 
      // 获取个人信息 
      @GET ( "/users/{user}" ) 
      Observable < UserListAdapter . GitHubUser >   getUserData ( @Path ( "user" )   String   user ) ; 
      // 获取库, 获取的是数组 
      @GET ( "/users/{user}/repos" ) 
      Observable < RepoListAdapter . GitHubRepo [ ] >   getRepoData ( @Path ( "user" )   String   user ) ; 
 } 
 

显示用户

详情页面与主页类似, 参考代码, 不做细说.

线程安全

Rx的好处之一就是可以防止内存泄露, 即根据页面生命周期, 处理异步线程的结束. 可以使用RxLifecycle库处理生命周期.

Activity类继承RxAppCompatActivity, 替换AppCompatActivity.

启动一个循环线程.

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 /** 
 * Rx的线程安全 
 * <p> 
 * Created by wangchenlong on 15/12/31. 
 */ 
 public   class   SafeActivity   extends   RxAppCompatActivity   { 
      private   static   final   String   TAG   =   "DEBUG-WCL: "   +   SafeActivity . class . getSimpleName ( ) ; 
      @Bind ( R . id . simple_tv_text )   TextView  mTvText ; 
      @Override   protected   void   onCreate ( Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_simple ) ; 
          ButterKnife . bind ( this ) ; 
          Observable . interval ( 1 ,   TimeUnit . SECONDS ) 
                  . observeOn ( AndroidSchedulers . mainThread ( ) ) 
                  . compose ( bindToLifecycle ( ) )   // 管理生命周期, 防止内存泄露 
                  . subscribe ( this :: showTime ) ; 
      } 
      private   void   showTime ( Long   time )   { 
          mTvText . setText ( String . valueOf ( "时间计数: "   +   time ) ) ; 
          Log . d ( TAG ,   "时间计数器: "   +   time ) ; 
      } 
      @Override 
      protected   void   onPause ( )   { 
          super . onPause ( ) ; 
          Log . w ( TAG ,   "页面关闭!" ) ; 
      } 
 } 
 

继承RxAppCompatActivity, 添加bindToLifecycle方法管理生命周期. 当页面onPause时, 会自动结束循环线程. 如果注释这句代码, 则会导致内存泄露.

RxBinding

RxBinding是Rx中处理控件异步调用的方式, 也是由Square公司开发, Jake负责编写. 通过绑定组件, 异步获取事件, 并进行处理. 编码风格非常优雅.

除了RxJava, 再添加RxBinding的依赖.

 
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 // RxBinding 
 compile   'com.jakewharton.rxbinding:rxbinding:0.3.0' 
 compile   'com.jakewharton.rxbinding:rxbinding-appcompat-v7:0.3.0' 
 compile   'com.jakewharton.rxbinding:rxbinding-design:0.3.0'

Toolbar和Fab, 两个较新的控件.

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 <? xml  version = "1.0"   encoding = "utf-8" ?> 
 < android . support . design . widget . CoordinatorLayout 
      xmlns : android = "http://schemas.android.com/apk/res/android" 
      xmlns : tools = "http://schemas.android.com/tools" 
      android : layout_width = "match_parent" 
      android : layout_height = "match_parent" 
      android : fitsSystemWindows = "true" 
      android : orientation = "vertical" 
      tools : context = ".BindingActivity" > 
      < android . support . design . widget . AppBarLayout 
          android : layout_width = "match_parent" 
          android : layout_height = "wrap_content" 
          android : theme = "@style/AppTheme.AppBarOverlay" > 
          < android . support . v7 . widget . Toolbar 
              android : id = "@+id/rxbinding_t_toolbar" 
              android : layout_width = "match_parent" 
              android : layout_height = "?attr/actionBarSize" 
              android : background = "?attr/colorPrimary" 
              android : popupTheme = "@style/AppTheme.PopupOverlay" 
              tools : targetApi = "21" / > 
      < / android . support . design . widget . AppBarLayout > 
      < include  layout = "@layout/content_rxbinding" / > 
      < android . support . design . widget . FloatingActionButton 
          android : id = "@+id/rxbinding_fab_fab" 
          android : layout_width = "wrap_content" 
          android : layout_height = "wrap_content" 
          android : layout_gravity = "bottom|end" 
          android : layout_margin = "@dimen/fab_margin" 
          android : src = "@android:drawable/ic_dialog_email" / > 
 < / android . support . design . widget . CoordinatorLayout > 
 

两个EditText控件, 对比传统方法和RxBinding方法.

 
 
 
 
 
 
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 <? xml  version = "1.0"   encoding = "utf-8" ?> 
 < LinearLayout  xmlns : android = "http://schemas.android.com/apk/res/android" 
                xmlns : app = "http://schemas.android.com/apk/res-auto" 
                xmlns : tools = "http://schemas.android.com/tools" 
                android : layout_width = "match_parent" 
                android : layout_height = "match_parent" 
                android : orientation = "vertical" 
                android : padding = "@dimen/activity_margin" 
                app : layout_behavior = "@string/appbar_scrolling_view_behavior" 
                tools : context = ".BindingActivity" 
                tools : showIn = "@layout/activity_binding" > 
      < TextView 
          android : layout_width = "match_parent" 
          android : layout_height = "wrap_content" 
          android : text = "@string/usual_approach" / > 
      < EditText 
          android : id = "@+id/rxbinding_et_usual_approach" 
          android : layout_width = "match_parent" 
          android : layout_height = "48dp" 
          android : hint = "@null" / > 
      < TextView 
          android : layout_width = "match_parent" 
          android : layout_height = "wrap_content" 
          android : text = "@string/reactive_approach" / > 
      < EditText 
          android : id = "@+id/rxbinding_et_reactive_approach" 
          android : layout_width = "match_parent" 
          android : layout_height = "48dp" 
          android : hint = "@null" / > 
      < TextView 
          android : id = "@+id/rxbinding_tv_show" 
          android : layout_width = "match_parent" 
          android : layout_height = "wrap_content" / > 
 < / LinearLayout > 
 

使用ButterKnife注入控件, 使用RxBinding方式绑定控件, 异步监听事件.

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 /** 
 * Rx绑定 
 * <p> 
 * Created by wangchenlong on 16/1/25. 
 */ 
 public   class   BindingActivity   extends   AppCompatActivity   { 
      @Bind ( R . id . rxbinding_t_toolbar )   Toolbar  mTToolbar ; 
      @Bind ( R . id . rxbinding_et_usual_approach )   EditText  mEtUsualApproach ; 
      @Bind ( R . id . rxbinding_et_reactive_approach )   EditText  mEtReactiveApproach ; 
      @Bind ( R . id . rxbinding_tv_show )   TextView  mTvShow ; 
      @Bind ( R . id . rxbinding_fab_fab )   FloatingActionButton  mFabFab ; 
      @Override   protected   void   onCreate ( @Nullable   Bundle  savedInstanceState )   { 
          super . onCreate ( savedInstanceState ) ; 
          setContentView ( R . layout . activity_binding ) ; 
          ButterKnife . bind ( this ) ; 
          initToolbar ( ) ;   // 初始化Toolbar 
          initFabButton ( ) ;   // 初始化Fab按钮 
          initEditText ( ) ;   // 初始化编辑文本 
      } 
      // 初始化Toolbar 
      private   void   initToolbar ( )   { 
          // 添加菜单按钮 
          setSupportActionBar ( mTToolbar ) ; 
          ActionBar  actionBar   =   getSupportActionBar ( ) ; 
          // 添加浏览按钮 
          if   ( actionBar   !=   null )   { 
              actionBar . setDisplayHomeAsUpEnabled ( true ) ; 
          } 
          RxToolbar . itemClicks ( mTToolbar ) . subscribe ( this :: onToolbarItemClicked ) ; 
          RxToolbar . navigationClicks ( mTToolbar ) . subscribe ( this :: onToolbarNavigationClicked ) ; 
      } 
      // 点击Toolbar的项 
      private   void   onToolbarItemClicked ( MenuItem  menuItem )   { 
          String   m   =   "点击\""   +   menuItem . getTitle ( )   +   "\"" ; 
          Toast . makeText ( this ,   m ,   Toast . LENGTH_SHORT ) . show ( ) ; 
      } 
      // 浏览点击 
      private   void   onToolbarNavigationClicked ( Void   v )   { 
          Toast . makeText ( this ,   "浏览点击" ,   Toast . LENGTH_SHORT ) . show ( ) ; 
      } 
      @Override   public   boolean   onCreateOptionsMenu ( Menu  menu )   { 
          getMenuInflater ( ) . inflate ( R . menu . menu_rxbinding ,   menu ) ; 
          return   super . onCreateOptionsMenu ( menu ) ; 
      } 
      // 初始化Fab按钮 
      private   void   initFabButton ( )   { 
          RxView . clicks ( mFabFab ) . subscribe ( this :: onFabClicked ) ; 
      } 
      // 点击Fab按钮 
      private   void   onFabClicked ( Void   v )   { 
          Snackbar  snackbar   =   Snackbar . make ( findViewById ( android . R . id . content ) ,   "点击Snackbar" ,   Snackbar . LENGTH_SHORT ) ; 
          snackbar . show ( ) ; 
          RxSnackbar . dismisses ( snackbar ) . subscribe ( this :: onSnackbarDismissed ) ; 
      } 
      // 销毁Snackbar, event参考{Snackbar} 
      private   void   onSnackbarDismissed ( int   event )   { 
          String   text   =   "Snackbar消失代码:"   +   event ; 
          Toast . makeText ( this ,   text ,   Toast . LENGTH_SHORT ) . show ( ) ; 
      } 
      // 初始化编辑文本 
      private   void   initEditText ( )   { 
          // 正常方式 
          mEtUsualApproach . addTextChangedListener ( new   TextWatcher ( )   { 
              @Override 
              public   void   beforeTextChanged ( CharSequence   s ,   int   start ,   int   count ,   int   after )   { 
              } 
              @Override   public   void   onTextChanged ( CharSequence   s ,   int   start ,   int   before ,   int   count )   { 
                  mTvShow . setText ( s ) ; 
              } 
              @Override   public   void   afterTextChanged ( Editable   s )   { 
              } 
          } ) ; 
          // Rx方式 
          RxTextView . textChanges ( mEtReactiveApproach ) . subscribe ( mTvShow :: setText ) ; 
      } 
 } 
 