RxAndrod是Rxjava的android拓展版，常常用于:
1.异步操作,跟asyntask差不多吧。
2.做一些订阅。

项目地址:
https://github.com/ReactiveX/RxAndroid

项目demo

项目有个小demo，简单地展示了其作用，老实说，没看出有什么好用。

package io.reactivex.android.samples;

import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
import android.view.View;
import io.reactivex.Observable;
import io.reactivex.ObservableSource;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.CompositeDisposable;
import io.reactivex.observers.DisposableObserver;
import io.reactivex.schedulers.Schedulers;
import java.util.concurrent.Callable;

public class MainActivity extends Activity {
    private static final String TAG = "RxAndroidSamples";

    private final CompositeDisposable disposables = new CompositeDisposable(); //这个就当他是个组合包吧

    @Override protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);
        findViewById(R.id.button_run_scheduler).setOnClickListener(new View.OnClickListener() {
            @Override public void onClick(View v) {
                onRunSchedulerExampleButtonClicked();
            }
        });
    }

    @Override protected void onDestroy() {
        super.onDestroy();
        disposables.clear();  //估计是取消订阅吧
    }

    void onRunSchedulerExampleButtonClicked() {
        disposables.add(sampleObservable()
            // Run on a background thread
            .subscribeOn(Schedulers.io())   //跑在子线程
            // Be notified on the main thread
            .observeOn(AndroidSchedulers.mainThread())    //结果展示在主线程，所以下面的回调都在主线程
            .subscribeWith(new DisposableObserver<String>() {
                @Override public void onComplete() {
                    Log.d(TAG, "onComplete()");
                }

                @Override public void onError(Throwable e) {
                    Log.e(TAG, "onError()", e);
                }

                @Override public void onNext(String string) {
                    Log.d(TAG, "onNext() in "+Thread.currentThread().getName());
                    Log.d(TAG, "onNext(" + string + ")");
                }
            }));
    }

    static Observable<String> sampleObservable() {   //这个玩意跑在子线程
        return Observable.defer(new Callable<ObservableSource<? extends String>>() {
          @Override public ObservableSource<? extends String> call() throws Exception {
                // Do some long running operation
                SystemClock.sleep(5000);
                Log.d(TAG, "call() in "+Thread.currentThread().getName());
                return Observable.just("one", "two", "three", "four", "five");
            }
        });
    }
}

运行界面与结果:

界面.png

结果.png

上面这个例子跟asyntask没多大区别啊，耗时操作在doinbackgroud，结果在onpostresult。估计主要作用还是在订阅吧。

参考:
RxJava 和 RxAndroid