RxJava2的网络请求示例
-
- 单一的网络请求(OkHttp3)
- 使用框架 rx2-android-networking
- 利用zip结合多个接口的数据再更新 UI(Retrofit2)
- 利用flatMap多个网络请求依次依赖
- 利用concat 先读取缓存数据再读取网络请求
- 利用debounce减少频繁的网络请求
- 利用interval 间隔任务(RxJava2的心跳处理)
- 线程调度
单一的网络请求(OkHttp3)
采用 OkHttp3 配合 map , doOnNext , 线程切换做简单的网络请求
1、通过 Observable.create() 方法，调用 OkHttp 网络请求;
2、通过 map 操作符结合 Gson , 将 Response 转换为 bean 类;
3、通过 doOnNext() 方法，解析 bean 中的数据，并进行数据库存储等操作;
4、调度线程，在子线程进行耗时操作任务，在主线程更新 UI;
5、通过 subscribe(),根据请求成功或者失败来更新 UI。
Observable.create(new ObservableOnSubscribe() {
@Override
public void subscribe(@NonNull ObservableEmitter e) throws Exception {
Builder builder = new Builder()
.url("http://api.avatardata.cn/MobilePlace/LookUp?key=ec47b85086be4dc8b5d941f5abd37a4e&mobileNumber=13021671512")
.get();
Request request = builder.build();
Call call = new OkHttpClient().newCall(request);
Response response = call.execute();
e.onNext(response);
}
}).map(new Function() {
@Override
public MobileAddress apply(@NonNull Response response) throws Exception {
Log.e(TAG, "map 线程:" + Thread.currentThread().getName() + "\n");
if (response.isSuccessful()) {
ResponseBody body = response.body();
if (body != null) {
Log.e(TAG, "map:转换前:" + response.body());
return new Gson().fromJson(body.string(), MobileAddress.class);
}
}
return null;
}
}).observeOn(AndroidSchedulers.mainThread())
.doOnNext(new Consumer() {
@Override
public void accept(@NonNull MobileAddress s) throws Exception {
Log.e(TAG, "doOnNext 线程:" + Thread.currentThread().getName() + "\n");
mRxOperatorsText.append("\ndoOnNext 线程:" + Thread.currentThread().getName() + "\n");
Log.e(TAG, "doOnNext: 保存成功：" + s.toString() + "\n");
mRxOperatorsText.append("doOnNext: 保存成功：" + s.toString() + "\n");
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(@NonNull MobileAddress data) throws Exception {
Log.e(TAG, "subscribe 线程:" + Thread.currentThread().getName() + "\n");
mRxOperatorsText.append("\nsubscribe 线程:" + Thread.currentThread().getName() + "\n");
Log.e(TAG, "成功:" + data.toString() + "\n");
mRxOperatorsText.append("成功:" + data.toString() + "\n");
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "subscribe 线程:" + Thread.currentThread().getName() + "\n");
mRxOperatorsText.append("\nsubscribe 线程:" + Thread.currentThread().getName() + "\n");
Log.e(TAG, "失败：" + throwable.getMessage() + "\n");
mRxOperatorsText.append("失败：" + throwable.getMessage() + "\n");
}
}); 使用框架 rx2-android-networking
1、通过 Rx2AndroidNetworking 的 get() 方法获取 Observable 对象(已解析)；
2、调度线程，根据请求结果更新 UI。
Rx2AndroidNetworking.get("http://api.avatardata.cn/MobilePlace/LookUp?key=ec47b85086be4dc8b5d941f5abd37a4e&mobileNumber=13021671512")
.build()
.getObjectObservable(MobileAddress.class)
.observeOn(AndroidSchedulers.mainThread()) // 为doOnNext() 指定在主线程，否则报错
.doOnNext(new Consumer() {
@Override
public void accept(@NonNull MobileAddress data) throws Exception {
Log.e(TAG, "doOnNext:"+Thread.currentThread().getName()+"\n" );
mRxOperatorsText.append("\ndoOnNext:"+Thread.currentThread().getName()+"\n" );
Log.e(TAG,"doOnNext:"+data.toString()+"\n");
mRxOperatorsText.append("doOnNext:"+data.toString()+"\n");
}
})
.map(new Function() {
@Override
public ResultBean apply(@NonNull MobileAddress mobileAddress) throws Exception {
Log.e(TAG, "\n" );
mRxOperatorsText.append("\n");
Log.e(TAG, "map:"+Thread.currentThread().getName()+"\n" );
mRxOperatorsText.append("map:"+Thread.currentThread().getName()+"\n" );
return mobileAddress.getResult();
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(@NonNull ResultBean data) throws Exception {
Log.e(TAG, "subscribe 成功:"+Thread.currentThread().getName()+"\n" );
mRxOperatorsText.append("\nsubscribe 成功:"+Thread.currentThread().getName()+"\n" );
Log.e(TAG, "成功:" + data.toString() + "\n");
mRxOperatorsText.append("成功:" + data.toString() + "\n");
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "subscribe 失败:"+Thread.currentThread().getName()+"\n" );
mRxOperatorsText.append("\nsubscribe 失败:"+Thread.currentThread().getName()+"\n" );
Log.e(TAG, "失败："+ throwable.getMessage()+"\n" );
mRxOperatorsText.append("失败："+ throwable.getMessage()+"\n");
}
}); 利用zip结合多个接口的数据再更新 UI(Retrofit2)
zip 操作符可以把多个 Observable 的数据接口成一个数据源再发出去
public class Network {
private static GankApi gankApi;
private static OkHttpClient okHttpClient = new OkHttpClient();
public static GankApi getGankApi() {
if (gankApi == null) {
Retrofit retrofit = new Retrofit.Builder()
.client(okHttpClient)
.baseUrl("http://gank.io/api/")
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.build();
gankApi = retrofit.create(GankApi.class);
}
return gankApi;
}
} Observable observable1 = Rx2AndroidNetworking.get("http://api.avatardata.cn/MobilePlace/LookUp?key=ec47b85086be4dc8b5d941f5abd37a4e&mobileNumber=13021671512")
.build()
.getObjectObservable(MobileAddress.class);
Observable observable2 = Network.getGankApi()
.getCategoryData("Android",1,1);
Observable.zip(observable1, observable2, new BiFunction() {
@Override
public String apply(@NonNull MobileAddress mobileAddress, @NonNull CategoryResult categoryResult) throws Exception {
return "合并后的数据为：手机归属地："+mobileAddress.getResult().getMobilearea()+"人名："+categoryResult.results.get(0).who;
}
}).subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(@NonNull String s) throws Exception {
Log.e(TAG, "accept: 成功：" + s+"\n");
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "accept: 失败：" + throwable+"\n");
}
}); 利用flatMap多个网络请求依次依赖
flatMap 操作符可以让多个网络请求依次依赖,比如:
1、注册用户前先通过接口A获取当前用户是否已注册，再通过接口B注册;
2、注册后自动登录，先通过注册接口注册用户信息，注册成功后马上调用登录接口进行自动登录。
Rx2AndroidNetworking.get("http://www.tngou.net/api/food/list")
.addQueryParameter("rows", 1 + "")
.build()
.getObjectObservable(FoodList.class) // 发起获取食品列表的请求，并解析到FootList
.subscribeOn(Schedulers.io()) // 在io线程进行网络请求
.observeOn(AndroidSchedulers.mainThread()) // 在主线程处理获取食品列表的请求结果
.doOnNext(new Consumer() {
@Override
public void accept(@NonNull FoodList foodList) throws Exception {
// 先根据获取食品列表的响应结果做一些操作
Log.e(TAG, "accept: doOnNext :" + foodList.toString());
mRxOperatorsText.append("accept: doOnNext :" + foodList.toString()+"\n");
}
})
.observeOn(Schedulers.io()) // 回到 io 线程去处理获取食品详情的请求
.flatMap(new Function>() {
@Override
public ObservableSource apply(@NonNull FoodList foodList) throws Exception {
if (foodList != null && foodList.getTngou() != null && foodList.getTngou().size() > 0) {
return Rx2AndroidNetworking.post("http://www.tngou.net/api/food/show")
.addBodyParameter("id", foodList.getTngou().get(0).getId() + "")
.build()
.getObjectObservable(FoodDetail.class);
}
return null;
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(@NonNull FoodDetail foodDetail) throws Exception {
Log.e(TAG, "accept: success ：" + foodDetail.toString());
mRxOperatorsText.append("accept: success ：" + foodDetail.toString()+"\n");
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "accept: error :" + throwable.getMessage());
mRxOperatorsText.append("accept: error :" + throwable.getMessage()+"\n");
}
});
利用concat 先读取缓存数据再读取网络请求
实用场景中经常会用到缓存数据，以通过减少频繁的网络请求达到节约流量：
1、concat 可以做到不交错的发射两个甚至多个 Observable 的发射物;
2、并且只有前一个 Observable 终止（onComplete）才会订阅下一个 Observable”
/**
* 缓存管理器
*
* Author: nanchen
* Email: [email protected]
* Date: 2017-07-03 9:49
*/
public class CacheManager {
private static CacheManager instance;
private FoodList footListJson;
private CacheManager(){}
public static CacheManager getInstance(){
if (instance == null){
instance = new CacheManager();
}
return instance;
}
public FoodList getFoodListData(){
return this.footListJson;
}
public void setFoodListData(FoodList data){
this.footListJson = data;
}
} Observable<FoodList> cache = Observable.create(new ObservableOnSubscribe<FoodList>() {
@Override
public void subscribe(@NonNull ObservableEmitter<FoodList> e) throws Exception {
Log.e(TAG, "create当前线程:"+Thread.currentThread().getName() );
FoodList data = CacheManager.getInstance().getFoodListData();
// 在操作符 concat 中，只有调用 onComplete 之后才会执行下一个 Observable
if (data != null){ // 如果缓存数据不为空，则直接读取缓存数据，而不读取网络数据
isFromNet = false;
Log.e(TAG, "\nsubscribe: 读取缓存数据:" );
runOnUiThread(new Runnable() {
@Override
public void run() {
mRxOperatorsText.append("\nsubscribe: 读取缓存数据:\n");
}
});
e.onNext(data);
}else {
isFromNet = true;
runOnUiThread(new Runnable() {
@Override
public void run() {
mRxOperatorsText.append("\nsubscribe: 读取网络数据:\n");
}
});
Log.e(TAG, "\nsubscribe: 读取网络数据:" );
e.onComplete();
}
}
});
Observable<FoodList> network = Rx2AndroidNetworking.get("http://www.tngou.net/api/food/list")
.addQueryParameter("rows",10+"")
.build()
.getObjectObservable(FoodList.class);
// 两个 Observable 的泛型应当保持一致
Observable.concat(cache,network)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer<FoodList>() {
@Override
public void accept(@NonNull FoodList tngouBeen) throws Exception {
Log.e(TAG, "subscribe 成功:"+Thread.currentThread().getName() );
if (isFromNet){
mRxOperatorsText.append("accept : 网络获取数据设置缓存: \n");
Log.e(TAG, "accept : 网络获取数据设置缓存: \n"+tngouBeen.toString() );
CacheManager.getInstance().setFoodListData(tngouBeen);
}
mRxOperatorsText.append("accept: 读取数据成功:" + tngouBeen.toString()+"\n");
Log.e(TAG, "accept: 读取数据成功:" + tngouBeen.toString());
}
}, new Consumer<Throwable>() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "subscribe 失败:"+Thread.currentThread().getName() );
Log.e(TAG, "accept: 读取数据失败："+throwable.getMessage() );
mRxOperatorsText.append("accept: 读取数据失败："+throwable.getMessage()+"\n");
}
});利用debounce减少频繁的网络请求
情景：输入框数据变化或者点击一次按钮时就要进行网络请求，这样会产生大量的网络请求，而实际上又不需要，这时候可以通过 debounce 过滤掉发射频率过快的请求，需要依赖
compile 'com.jakewharton.rxbinding2:rxbinding:2.0.0'
RxView.clicks(mRxOperatorsBtn)
.debounce(2,TimeUnit.SECONDS) // 过滤掉发射频率小于2秒的发射事件
.subscribe(new Consumerprivate void clickBtn() {
Rx2AndroidNetworking.get("http://www.tngou.net/api/food/list")
.addQueryParameter("rows",2+"") // 只获取两条数据
.build()
.getObjectObservable(FoodList.class)
.subscribeOn(Schedulers.io()) // 在 io 线程进行网络请求
.observeOn(AndroidSchedulers.mainThread()) // 在主线程进行更新UI等操作
.subscribe(new Consumer() {
@Override
public void accept(@NonNull FoodList foodList) throws Exception {
Log.e(TAG, "accept: 获取数据成功:"+foodList.toString()+"\n" );
mRxOperatorsText.append("accept: 获取数据成功:"+foodList.toString()+"\n" );
}
}, new Consumer() {
@Override
public void accept(@NonNull Throwable throwable) throws Exception {
Log.e(TAG, "accept: 获取数据失败："+throwable.getMessage() +"\n");
mRxOperatorsText.append("accept: 获取数据失败："+throwable.getMessage() +"\n");
}
}); 利用interval 间隔任务(RxJava2的心跳处理)
可能我们会遇上各种即时通讯，如果是自己家开发的 IM 即时通讯，我相信在移动端一定少不了心跳包的管理，而我们 RxJava 2.x 的 interval 操作符棒我们解决了这个问题。
mDisposable = Flowable.interval(1, TimeUnit.SECONDS)
.doOnNext(new Consumer() {
@Override
public void accept(@NonNull Long aLong) throws Exception {
Log.e(TAG, "accept: doOnNext : "+aLong );
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(@NonNull Long aLong) throws Exception {
Log.e(TAG, "accept: 设置文本 ："+aLong );
mRxOperatorsText.append("accept: 设置文本 ："+aLong +"\n");
}
}); /** * 销毁时停止心跳 */
@Override protected void onDestroy() {
super.onDestroy();
if (mDisposable != null){
mDisposable.dispose();
}
线程调度
RxJava 内置的线程调度器的确可以让我们的线程切换得心应手，但其中也有些需要注意的地方。
简单地说，subscribeOn() 指定的就是发射事件的线程，observerOn指定的就是订阅者接收事件的线程。多次指定发射事件的线程只有第一次指定的有效，也就是说多次调用 subscribeOn() 只有第一次的有效，其余的会被忽略。
但多次指定订阅者接收线程是可以的，也就是说每调用一次 observerOn()，下游的线程就会切换一次。
Observable.create(new ObservableOnSubscribe<Integer>() {
@Override
public void subscribe(@NonNull ObservableEmitter<Integer> e) throws Exception {
Log.e(TAG, "Observable thread is : " + Thread.currentThread().getName());
e.onNext(1);
e.onComplete();
}
}).subscribeOn(Schedulers.newThread())
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.doOnNext(new Consumer<Integer>() {
@Override
public void accept(@NonNull Integer integer) throws Exception {
Log.e(TAG, "After observeOn(mainThread)，Current thread is " + Thread.currentThread().getName());
}
})
.observeOn(Schedulers.io())
.subscribe(new Consumer<Integer>() {
@Override
public void accept(@NonNull Integer integer) throws Exception {
Log.e(TAG, "After observeOn(io)，Current thread is " + Thread.currentThread().getName());
}
});