RxAndroid 官方demo理解

package com.rxandroid.test1;

import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Process;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;

import java.util.concurrent.TimeUnit;

import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.android.schedulers.HandlerScheduler;
import rx.exceptions.OnErrorThrowable;
import rx.functions.Func0;

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

    private Handler backgroundHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //创建子线程handler
        BackgroundThread backgroundThread = new BackgroundThread();
        backgroundThread.start();
        backgroundHandler = new Handler(backgroundThread.getLooper());

        findViewById(R.id.button_run_scheduler).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                onRunSchedulerExampleButtonClicked();
            }
        });
    }

    /**
     * 整个流程就如同 取款机：
     * 先输入取款数目，（订阅,要钱的需求）
     * 然后取款机自动吐出对应数目的钱（观察输入信号)
     */
    void onRunSchedulerExampleButtonClicked() {
        sampleObservable()
                // Run on a background thread
                .subscribeOn(HandlerScheduler.from(backgroundHandler))//订阅在子线程
                // Be notified on the main thread
                .observeOn(AndroidSchedulers.mainThread())//观察在主线程，也就是结果会在主线程中执行
                .subscribe(new Subscriber<String>() {
                    @Override
                    public void onCompleted() {
                        Log.d(TAG, "onCompleted()");
                        Log.d(TAG, "SubscriberThread:" + Thread.currentThread().getName());//Main
                    }

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

                    @Override
                    public void onNext(String string) {//这将会在主线程中执行
                        Log.d(TAG, "onNext(" + string + ")");
                    }
                });
    }

    static Observable<String> sampleObservable() {
        return Observable.defer(new Func0<Observable<String>>() {//定义一个方法，接口中的方法返回Observable<String>
            @Override
            public Observable<String> call() {
                try {
                    // Do some long running operation
                    Thread.sleep(TimeUnit.SECONDS.toMillis(5));//睡眠5s
                    Log.d(TAG, "ObservableThread:" + Thread.currentThread().getName());
                } catch (InterruptedException e) {
                    throw OnErrorThrowable.from(e);
                }
                return Observable.just("one", "two", "three", "four", "five");//发布5个字符串，子线程中
            }
        });
    }

    /**
     * 创建子线程的handler或者说looper
     */
    static class BackgroundThread extends HandlerThread {
        BackgroundThread() {
            super("SchedulerSample-BackgroundThread", Process.THREAD_PRIORITY_BACKGROUND);
        }

    }
}