在看一個例子

package com.example.acer.temp;


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

import java.util.ArrayList;
import java.util.List;

import rx.Observable;
import rx.Observer;

public class MainActivity extends AppCompatActivity
 
 {
    Observable<Integer>  observableString;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        List<Integer>  item=new ArrayList<>();
        item.add(1);
        item.add(2
 
);
        item.add(3);
        //使用該方法，那麼觀察者介面中只調用OnCompleted方法
      observableString=Observable.empty();


    }
    public void myClick(View v){
        observableString.subscribe(new Observer<Integer>() {
            @Override
            public void onCompleted() {
                Log.i("zhang_xin"
 
,"onCompleted");
            }

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

            @Override
            public void onNext(Integer integer) {
                Log.i("zhang_xin",integer+"");
            }
        });
    }
}

這是列印輸出語句

10-11 21:26:02.167 10954-10954/com.example.acer.temp I/zhang_xin: onCompleted