關於Bound Services的常用方式

利用服務播放音樂的實例，大部分採用SDK上的方式,

MainActivity:

package com.example.androidtest;
import com.example.androidtest.myService.LocalBinder;
import android.os.Bundle;
import android.os.IBinder;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
    protected myService mService;//用於保存sevice所返回的myService對象,以調用Service中所提供的方法
    protected boolean mBound;//用於判斷綁定情況
    private ServiceConnection mConnection = new ServiceConnection() {//作爲bindService參數，在綁定後將調用 onServiceConnected，並接受到返回的IBinder對象，該對象可用於獲取service所要提供的數據，本例中由於在服務中的LocalBinder添加了getService方法，故可用於獲取myService對象
        @Override
        public void onServiceConnected(ComponentName className, IBinder service) {
            LocalBinder binder = (LocalBinder) service;
            mService = binder.getService();
            mBound = true;
        }
        @Override
        public void onServiceDisconnected(ComponentName arg0) {//在unbindService後調用，用作清理資源
            mBound = false;
            mService.stopMusic();
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bindService(new Intent(this, myService.class), mConnection,
                Context.BIND_AUTO_CREATE);//綁定服務
        Button startButton = (Button) findViewById(R.id.button1);
        Button pauseButton = (Button) findViewById(R.id.button2);
        Button stopButton = (Button) findViewById(R.id.button3);
        startButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                mService.playMusic();
                // TODO Auto-generated method stub
            }
        });
        pauseButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                mService.pauseMusic();
                // TODO Auto-generated method stub
            }
        });
        stopButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                mService.stopMusic();
            }
        });
    }
    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        if (mBound == true) {
            unbindService(mConnection);//解除綁定
        }
    }
}

myService：

package com.example.androidtest;
import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
public class myService extends Service {
    private  LocalBinder localBinder=new LocalBinder();;
    private  MediaPlayer mediaPlayer;//創建一個以raw/music爲播放文件的MediaPlayer對象，可用於播放音樂
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        mediaPlayer=MediaPlayer.create(myService.this,R.raw.music);
        return  localBinder;
    }
    //創建內部類作爲onBind返回值，用於給客戶端獲取服務端的載體
    public class LocalBinder extends Binder {
        myService getService() {//直接返回myService對象，個人認爲此種方法比較簡單，也可在此創建其他需要返回給客戶端的方法，用於通信
            return myService.this;
        }
    }
    //客戶端可調用方法：
    public void playMusic() {
        mediaPlayer.start();
    }
    public void pauseMusic() {
        mediaPlayer.pause();
    }
    public void stopMusic(){
        mediaPlayer.stop();
    }
}