Android 跨進程通Messenger(簡單易懂)_Android

不需要AIDL也不需要複雜的ContentProvider，也不需要SharedPreferences或者共用隱藏檔！

只需要簡單易懂的Messenger，它也稱為信使，通過它可以在不同進程中傳遞message對象，在message中放入我們需要傳遞的資料你就可以實現跨進程通訊和傳遞資料。廢話不多說，直接上代碼。

首先是服務端：

public class Ser extends Service{@Overridepublic IBinder onBind(Intent intent) {return messenger.getBinder();}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {// TODO Auto-generated method stubLog.i("Service", "onStartCommand()");return super.onStartCommand(intent, flags, startId);}public Messenger messenger = new Messenger(new MyHandler());public class MyHandler extends Handler{@Overridepublic void handleMessage(Message msg) {Log.i("Ser---TAG", "msg::"+msg.arg1+"want :"+msg.getData().getString("msg"));Messenger messenger = msg.replyTo;Message message = Message.obtain(null, 0);Bundle bundle = new Bundle();bundle.putString("reply", "嗯,你的訊息我已經收到,稍後回複你!");message.setData(bundle);try {messenger.send(message);} catch (RemoteException e) {e.printStackTrace();}super.handleMessage(msg);}}

我們在服務端操作了並不多，僅僅是執行個體化了一個Messenger，並且建立了一個handler用來接收用戶端發送過來的訊息

接下來看用戶端：

public class Client extends Service{private static final String TAG = "Client";protected Messenger mService;public Handler handler = new Handler(){public void handleMessage(Message msg) {Log.i("client --- TAG", "msg:;"+msg.getData().getString("reply"));};};public Messenger messenger = new Messenger(handler);@Overridepublic IBinder onBind(Intent intent) {return null;}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {Intent mIntent = new Intent();mIntent.setClassName("com.example.test1", "com.example.test1.Ser");bindService(mIntent, mBindService, Context.BIND_AUTO_CREATE);return super.onStartCommand(intent, flags, startId);}@Overridepublic void onDestroy() {super.onDestroy();unbindService(mBindService);}private ServiceConnection mBindService = new ServiceConnection(){@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {mService = new Messenger(service);Message message = Message.obtain(null, 0);Bundle bundle = new Bundle();bundle.putString("msg", "hello this is client!");message.replyTo = messenger;message.setData(bundle);try {mService.send(message);} catch (RemoteException e) {e.printStackTrace();}}@Overridepublic void onServiceDisconnected(ComponentName name) {// TODO Auto-generated method stub}};}

同樣用戶端也需要一個handler來接收服務端返回的訊息，還有很關鍵的一點

當用戶端發送訊息的時候，需要把接收服務端回複的Messenger通過Message的

replyTo參數傳遞給服務端，否則會報NullPointerException。然後我們在看下log

"hello this is client!" 這是用戶端發給服務端的，證明服務端已經收到！

"嗯,你的訊息我已經收到,稍後回複你!" 這是服務端返回給用戶端的，證明用戶端也收到了，並且還是即時通訊哦,到此我們的跨進程傳遞資料通訊完整結束啦，是不是很簡單！