详细解析 RxAndroid 的使用方式

来源：互联网发布：abb工业机器人编程编辑：程序博客网时间：2024/06/06 03:22

原文出处： C.L. Wang（@SpikeKing ）

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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 65.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 200.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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plugins{
    id"me.tatarka.retrolambda"version"3.2.4"
}
 
android{
...
 
    compileOptions{
        sourceCompatibilityJavaVersion.VERSION_1_8
        targetCompatibilityJavaVersion.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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 590.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* 主Activity, 用于跳转各个模块.
*
* @author wangchenlong
*/
publicclassMainActivityextendsAppCompatActivity{
 
    @Override
    protectedvoidonCreate(BundlesavedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
 
    // 跳转简单的页面
    publicvoidgotoSimpleModule(Viewview){
        startActivity(newIntent(this,SimpleActivity.class));
    }
 
    // 跳转复杂的页面
    publicvoidgotoMoreModule(Viewview){
        startActivity(newIntent(this,MoreActivity.class));
    }
 
    // 跳转Lambda的页面
    publicvoidgotoLambdaModule(Viewview){
        startActivity(newIntent(this,LambdaActivity.class));
    }
 
    // 跳转网络的页面
    publicvoidgotoNetworkModule(Viewview){
        startActivity(newIntent(this,NetworkActivity.class));
    }
 
    // 跳转线程安全的页面
    publicvoidgotoSafeModule(Viewview){
        startActivity(newIntent(this,SafeActivity.class));
    }
}

在SimpleActivity中, 创建一个观察者, 收到字符串的返回.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 236.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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// 观察事件发生
    Observable.OnSubscribemObservableAction=newObservable.OnSubscribe<String>(){
        @Overridepublicvoidcall(Subscriber<?superString>subscriber){
            subscriber.onNext(sayMyName());// 发送事件
            subscriber.onCompleted();// 完成事件
        }
    };
 
...
 
    // 创建字符串
    privateStringsayMyName(){
        return"Hello, I am your friend, Spike!";
    }

创建两个订阅者, 使用字符串输出信息.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 461.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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// 订阅者, 接收字符串, 修改控件
Subscriber<String>mTextSubscriber=newSubscriber<String>(){
    @OverridepublicvoidonCompleted(){
 
    }
 
    @OverridepublicvoidonError(Throwablee){
 
    }
 
    @OverridepublicvoidonNext(Strings){
        mTvText.setText(s);// 设置文字
    }
};
 
// 订阅者, 接收字符串, 提示信息
Subscriber<String>mToastSubscriber=newSubscriber<String>(){
    @OverridepublicvoidonCompleted(){
 
    }
 
    @OverridepublicvoidonError(Throwablee){
 
    }
 
    @OverridepublicvoidonNext(Strings){
        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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 236.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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@OverrideprotectedvoidonCreate(BundlesavedInstanceState){
    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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 1226.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* 更多的RxAndroid的使用方法.
* <p>
* Created by wangchenlong on 15/12/30.
*/
publicclassMoreActivityextendsActivity{
 
    @Bind(R.id.simple_tv_text)TextViewmTvText;
 
    finalString[]mManyWords={"Hello","I","am","your","friend","Spike"};
    finalList<String>mManyWordList=Arrays.asList(mManyWords);
 
    // Action类似订阅者, 设置TextView
    privateAction1<String>mTextViewAction=newAction1<String>(){
        @Overridepublicvoidcall(Strings){
            mTvText.setText(s);
        }
    };
 
    // Action设置Toast
    privateAction1<String>mToastAction=newAction1<String>(){
        @Overridepublicvoidcall(Strings){
            Toast.makeText(MoreActivity.this,s,Toast.LENGTH_SHORT).show();
        }
    };
 
    // 设置映射函数
    privateFunc1<List<String>,Observable<String>>mOneLetterFunc=newFunc1<List<String>,Observable<String>>(){
        @OverridepublicObservable<String>call(List<String>strings){
            returnObservable.from(strings);// 映射字符串
        }
    };
 
    // 设置大写字母
    privateFunc1<String,String>mUpperLetterFunc=newFunc1<String,String>(){
        @OverridepublicStringcall(Strings){
            returns.toUpperCase();// 大小字母
        }
    };
 
    // 连接字符串
    privateFunc2<String,String,String>mMergeStringFunc=newFunc2<String,String,String>(){
        @OverridepublicStringcall(Strings,Strings2){
            returnString.format("%s %s",s,s2);// 空格连接字符串
        }
    };
 
    @Override
    protectedvoidonCreate(BundlesavedInstanceState){
        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
    privateStringsayMyName(){
        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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 110.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 110.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 110.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 851.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* Lambda表达式写法
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassLambdaActivityextendsActivity{
 
    @Bind(R.id.simple_tv_text)TextViewmTvText;
 
    finalString[]mManyWords={"Hello","I","am","your","friend","Spike"};
    finalList<String>mManyWordList=Arrays.asList(mManyWords);
 
    @OverrideprotectedvoidonCreate(BundlesavedInstanceState){
        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
    privateStringsayMyName(){
        return"Hello, I am your friend, Spike!";
    }
 
    // 显示Toast
    privatevoidshowToast(Strings){
        Toast.makeText(LambdaActivity.this,s,Toast.LENGTH_SHORT).show();
    }
 
    // 合并字符串
    privateStringmergeString(Strings1,Strings2){
        returnString.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

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 131.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 551.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* Rx的网络请求方式
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassNetworkActivityextendsActivity{
 
    @Bind(R.id.network_rv_list)RecyclerViewmRvList;// 列表
 
    @OverrideprotectedvoidonCreate(BundlesavedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_network);
        ButterKnife.bind(this);
 
        // 设置Layout管理器
        LinearLayoutManagerlayoutManager=newLinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRvList.setLayoutManager(layoutManager);
 
        // 设置适配器
        UserListAdapteradapter=newUserListAdapter(this::gotoDetailPage);
        NetworkWrapper.getUsersInto(adapter);
        mRvList.setAdapter(adapter);
    }
 
    // 点击的回调
    publicinterfaceUserClickCallback{
        voidonItemClicked(Stringname);
    }
 
    // 跳转到库详情页面
    privatevoidgotoDetailPage(Stringname){
        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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 1106.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* 显示列表
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassUserListAdapterextendsRecyclerView.Adapter<UserListAdapter.UserViewHolder>{
 
    privateList<GitHubUser>mUsers;// 用户名集合
 
    privateNetworkActivity.UserClickCallbackmCallback;// 用户点击项的回调
 
    publicUserListAdapter(NetworkActivity.UserClickCallbackcallback){
        mUsers=newArrayList<>();
        mCallback=callback;
    }
 
    publicvoidaddUser(GitHubUseruser){
        mUsers.add(user);
        notifyItemInserted(mUsers.size()-1);// 最后一位
    }
 
    @OverridepublicUserViewHolderonCreateViewHolder(ViewGroupparent,intviewType){
        Viewitem=LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_network_user,parent,false);
        returnnewUserViewHolder(item,mCallback);
    }
 
    @OverridepublicvoidonBindViewHolder(UserViewHolderholder,intposition){
        holder.bindTo(mUsers.get(position));
    }
 
    @OverridepublicintgetItemCount(){
        returnmUsers.size();
    }
 
    // Adapter的ViewHolder
    publicstaticclassUserViewHolderextendsRecyclerView.ViewHolder{
 
        @Bind(R.id.network_item_iv_user_picture)ImageViewmIvUserPicture;
        @Bind(R.id.network_item_tv_user_name)TextViewmTvUserName;
        @Bind(R.id.network_item_tv_user_login)TextViewmTvUserLogin;
        @Bind(R.id.network_item_tv_user_page)TextViewmTvUserPage;
 
        publicUserViewHolder(ViewitemView,NetworkActivity.UserClickCallbackcallback){
            super(itemView);
            ButterKnife.bind(this,itemView);
            // 绑定点击事件
            itemView.setOnClickListener(v->
                    callback.onItemClicked(mTvUserLogin.getText().toString()));
        }
 
        // 绑定数据
        publicvoidbindTo(GitHubUseruser){
            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
    publicstaticclassGitHubUser{
        publicStringlogin;
        publicStringavatar_url;
        publicStringname;
        publicStringrepos_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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 521.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* 用户获取类
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassNetworkWrapper{
    privatestaticfinalString[]mFamousUsers=
            {"SpikeKing","JakeWharton","rock3r","Takhion","dextorer","Mariuxtheone"};
 
    // 获取用户信息
    publicstaticvoidgetUsersInto(finalUserListAdapteradapter){
        GitHubServicegitHubService=
                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
    publicstaticvoidgetReposInfo(finalStringusername,finalRepoListAdapteradapter){
        GitHubServicegitHubService=
                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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 521.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* 用户获取类
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassNetworkWrapper{
    privatestaticfinalString[]mFamousUsers=
            {"SpikeKing","JakeWharton","rock3r","Takhion","dextorer","Mariuxtheone"};
 
    // 获取用户信息
    publicstaticvoidgetUsersInto(finalUserListAdapteradapter){
        GitHubServicegitHubService=
                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
    publicstaticvoidgetReposInfo(finalStringusername,finalRepoListAdapteradapter){
        GitHubServicegitHubService=
                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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 266.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* GitHub的服务
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicinterfaceGitHubService{
    StringENDPOINT="https://api.github.com";
 
    // 获取个人信息
    @GET("/users/{user}")
    Observable<UserListAdapter.GitHubUser>getUserData(@Path("user")Stringuser);
 
    // 获取库, 获取的是数组
    @GET("/users/{user}/repos")
    Observable<RepoListAdapter.GitHubRepo[]>getRepoData(@Path("user")Stringuser);
}

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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 506.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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/**
* Rx的线程安全
* <p>
* Created by wangchenlong on 15/12/31.
*/
publicclassSafeActivityextendsRxAppCompatActivity{
    privatestaticfinalStringTAG="DEBUG-WCL: "+SafeActivity.class.getSimpleName();
 
    @Bind(R.id.simple_tv_text)TextViewmTvText;
 
    @OverrideprotectedvoidonCreate(BundlesavedInstanceState){
        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);
    }
 
    privatevoidshowTime(Longtime){
        mTvText.setText(String.valueOf("时间计数: "+time));
        Log.d(TAG,"时间计数器: "+time);
    }
 
    @Override
    protectedvoidonPause(){
        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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 80.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 560.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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<?xmlversion="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>
 
    <includelayout="@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.

Java
<textarea wrap="soft" class="crayon-plain print-no" data-settings="dblclick" readonly="readonly" style="border-width: 0px; outline: none; display: block; -webkit-appearance: none; padding-top: 0px; padding-right: 5px; padding-left: 5px; width: 608px; height: 626.5px; resize: none; overflow: auto; margin: 0px; position: absolute; opacity: 0; box-shadow: none; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; -webkit-box-shadow: none; white-space: pre; word-wrap: normal; color: rgb(0, 0, 0); tab-size: 4; z-index: 0; line-height: 15px !important; font-family: Monaco, MonacoRegular, 'Courier New', monospace !important;"></textarea>
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<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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.

Java
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/**
* Rx绑定
* <p>
* Created by wangchenlong on 16/1/25.
*/
publicclassBindingActivityextendsAppCompatActivity{
 
    @Bind(R.id.rxbinding_t_toolbar)ToolbarmTToolbar;
    @Bind(R.id.rxbinding_et_usual_approach)EditTextmEtUsualApproach;
    @Bind(R.id.rxbinding_et_reactive_approach)EditTextmEtReactiveApproach;
    @Bind(R.id.rxbinding_tv_show)TextViewmTvShow;
    @Bind(R.id.rxbinding_fab_fab)FloatingActionButtonmFabFab;
 
    @OverrideprotectedvoidonCreate(@NullableBundlesavedInstanceState){
        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
    privatevoidinitToolbar(){
        // 添加菜单按钮
        setSupportActionBar(mTToolbar);
        ActionBaractionBar=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
    privatevoidonToolbarItemClicked(MenuItemmenuItem){
        Stringm="点击\""+menuItem.getTitle()+"\"";
        Toast.makeText(this,m,Toast.LENGTH_SHORT).show();
    }
 
    // 浏览点击
    privatevoidonToolbarNavigationClicked(Voidv){
        Toast.makeText(this,"浏览点击",Toast.LENGTH_SHORT).show();
    }
 
    @OverridepublicbooleanonCreateOptionsMenu(Menumenu){
        getMenuInflater().inflate(R.menu.menu_rxbinding,menu);
        returnsuper.onCreateOptionsMenu(menu);
    }
 
    // 初始化Fab按钮
    privatevoidinitFabButton(){
        RxView.clicks(mFabFab).subscribe(this::onFabClicked);
    }
 
    // 点击Fab按钮
    privatevoidonFabClicked(Voidv){
        Snackbarsnackbar=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}
    privatevoidonSnackbarDismissed(intevent){
        Stringtext="Snackbar消失代码:"+event;
        Toast.makeText(this,text,Toast.LENGTH_SHORT).show();
    }
 
    // 初始化编辑文本
    privatevoidinitEditText(){
        // 正常方式
        mEtUsualApproach.addTextChangedListener(newTextWatcher(){
            @Override
            publicvoidbeforeTextChanged(CharSequences,intstart,intcount,intafter){
 
            }
 
            @OverridepublicvoidonTextChanged(CharSequences,intstart,intbefore,intcount){
                mTvShow.setText(s);
            }
 
            @OverridepublicvoidafterTextChanged(Editables){
 
            }
 
        });
 
        // Rx方式
        RxTextView.textChanges(mEtReactiveApproach).subscribe(mTvShow::setText);
    }
}

Toolbar使用RxToolbar监听点击事件; Snackbar使用RxSnackbar监听;
EditText使用RxTextView监听; 其余使用RxView监听.

OK, That’s all. Enjoy it!

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