一、Service簡介

Service有local和remote兩種類型。

local主要是用于本地的應用程序之間的調用，remote主要用于不同應用之間的重用，這里用到AIDL IPC機制。 關于AIDL IPC機制可以參閱SDK Dev Guide，很簡單！當然，你要是想完全理解這種機制可能要花費點時間喲，不過還好，我只是用一下，呵呵！~ ~

二、Service與進程

android各個組件之間默認運行在同一個進程之中，它們有各自所在的進程來管理，它們是主線程的一部分而不是系統開啟的線程。

這么說來， 要是 在這些組件中做耗時比較長的操作需要另起線程。

這里需要說明，你可以通過android：process=屬性說明應用組建的所屬進程。

三、遠程Service

先看看文件目錄結構吧

在對應的包下面新建一個AIDL文件，這里是IMusicService.aidl文件。那么ADT會自動的為你生成對應的java源文件。不要以為 IMusicService.aidl多難寫，其實它就是你暴露給外界的接口，只不過我們把他的后綴寫為.aidl而不是.java。

IMusicService.aidl文件：

package csdn.blog.myaidl; interface IMusicService { void play(); void stop(); void pause(); }

這樣，我們就可以在應用程序中使用它啦...

package csdn.blog; import java.io.IOException; import android.app.Service; import android.content.Intent; import android.media.MediaPlayer; import android.os.IBinder; import android.os.RemoteException; import android.util.Log; import csdn.blog.myaidl.IMusicService; public class MusicPlayerService extends Service { //debug private static final String TAG = "Service_06_Remote"; private MediaPlayer mPlayer = null; private IMusicService.Stub binder = new IMusicService.Stub() { @Override public void stop() throws RemoteException { // TODO Auto-generated method stub if(mPlayer != null) { mPlayer.stop(); try { mPlayer.prepare(); } catch (IllegalStateException e) { Log.e(TAG, e.toString()); } catch (IOException e) { Log.e(TAG, e.toString()); } } } @Override public void play() throws RemoteException { // TODO Auto-generated method stub if(mPlayer == null) { mPlayer = MediaPlayer.create(MusicPlayerService.this, R.raw.tiger); } if(! mPlayer.isPlaying()) { mPlayer.start(); } } @Override public void pause() throws RemoteException { // TODO Auto-generated method stub if(mPlayer != null && mPlayer.isPlaying()) { mPlayer.pause(); } } }; @Override public void onCreate() { // TODO Auto-generated method stub //Log.d(TAG, "MusicPlayerService-->onCreate--onBind");//無效 //debug 線程 System.out.println("MusicPlayerService Id-->" + Thread.currentThread().getId()); System.out.println("MusicPlayerService Name-->" + Thread.currentThread().getName()); System.out.println("MusicPlayerService-->onCreate--onBind"); super.onCreate(); } @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub try { binder.play(); } catch (RemoteException e) { Log.e(TAG, e.toString()); } //Log.d(TAG, "log MusicPlayerService-->onBind");//無效 System.out.println("MusicPlayerService-->onBind"); return binder; } @Override public boolean onUnbind(Intent intent) { // TODO Auto-generated method stub //Log.d(TAG, "MusicPlayerService-->onUnbind");//無效 System.out.println("MusicPlayerService-->onUnbind"); return super.onUnbind(intent); } @Override public void onDestroy() { // TODO Auto-generated method stub //Log.d(TAG, "MusicPlayerService-->onDestroy");//無效 System.out.println("MusicPlayerService-->onDestroy"); mPlayer.stop(); mPlayer.release(); super.onDestroy(); } }

Activity中我是這樣做的：

package csdn.blog; import android.app.Activity; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.ServiceConnection; import android.os.Bundle; import android.os.IBinder; import android.os.RemoteException; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import csdn.blog.myaidl.IMusicService; public class Service_06_RemoteAct extends Activity implements OnClickListener{ private static final String TAG = "Service_06_RemoteAct"; private static final String SERVICE_ACTION = "csdn.blog.MusicPlayerService"; private Button btnPlay, btnStop, btnPause, btnExit = null; private IMusicService mIMusicPlayerService = null; private ServiceConnection mConnection = new ServiceConnection() { @Override public void onServiceDisconnected(ComponentName name) { // TODO Auto-generated method stub Log.d(TAG, "onServiceDisconnected()"); mIMusicPlayerService = null; } @Override public void onServiceConnected(ComponentName name, IBinder service) { // TODO Auto-generated method stub Log.d(TAG, "onServiceConnected()"); mIMusicPlayerService = IMusicService.Stub.asInterface(service); } }; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //debug 線程 System.out.println("main Id-->" + Thread.currentThread().getId()); System.out.println("main Name-->" + Thread.currentThread().getName()); btnPlay = (Button)findViewById(R.id.button_play); btnStop = (Button)findViewById(R.id.button_stop); btnPause = (Button)findViewById(R.id.button_pause); btnExit = (Button)findViewById(R.id.button_exit); btnPlay.setOnClickListener(this); btnStop.setOnClickListener(this); btnPause.setOnClickListener(this); btnExit.setOnClickListener(this); connection(); } @Override protected void onDestroy() { // TODO Auto-generated method stub Log.d(TAG, "onDestroy-->unbindService"); unbindService(mConnection); super.onDestroy(); } private void connection() { // TODO Auto-generated method stub Log.d(TAG, "bindService"); bindService(new Intent(SERVICE_ACTION), mConnection, Context.BIND_AUTO_CREATE); } @Override public void onClick(View v) { // TODO Auto-generated method stub switch(v.getId()) { case R.id.button_play: try { mIMusicPlayerService.play(); } catch (RemoteException e) { Log.e(TAG, e.toString()); } break; case R.id.button_stop: try { mIMusicPlayerService.stop(); } catch (RemoteException e) { Log.e(TAG, e.toString()); } break; case R.id.button_pause: try { mIMusicPlayerService.pause(); } catch (RemoteException e) { Log.e(TAG, e.toString()); } break; case R.id.button_exit: finish(); break; default: break; } } }

最后，別忘記在manifest.xm文件中聲明：

<!--android:process=":remote" 表示該服務在另一個進程之中 這句代碼寫不寫均可以正常運行。 ":remote"只是一個標識符，可以任意取名如："anyName"等 --> <service android:name=".MusicPlayerService" android:process=":remote"> <intent-filter> <action android:name="csdn.blog.MusicPlayerService"/> </intent-filter> </service

cmd一下，在命令行中adb shell ps 查看 android 應用程序的 PID 以及進程 ID。

Android(三)：遠程Service基本操作