Android使用Messenger实现service与activity交互

public class MessengerService extends Service { final Messenger mMessenger = new Messenger(new IncomingHandler()); @Override public IBinder onBind(Intent intent) {  return mMessenger.getBinder(); } @SuppressLint("HandlerLeak") class IncomingHandler extends Handler {  @Override  public void handleMessage(Message msg) {   switch (msg.what) {   case 0:    Toast.makeText(MessengerService.this,"Hello lenve!", Toast.LENGTH_LONG).show();    break;   case 1:    Toast.makeText(MessengerService.this,"Hello lenve!Hello world!", Toast.LENGTH_LONG).show();    break;   default:    break;   }  } }}

public class MainActivity extends Activity { private Messenger mMessenger; private ServiceConnection conn; private Intent intent; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  intent = new Intent(this,MessengerService.class);  conn = new ServiceConnection() {   @Override   public void onServiceDisconnected(ComponentName name) {    mMessenger = null;   }   @Override   public void onServiceConnected(ComponentName name, IBinder service) {    mMessenger = new Messenger(service);   }  }; } @Override protected void onStart() {  super.onStart();  bindService(intent, conn, BIND_AUTO_CREATE); } @Override protected void onStop() {  super.onStop();  unbindService(conn); } public void onClick(View v){  Message msg = null;  switch (v.getId()) {  case R.id.button1:   msg = Message.obtain(null, 0, 0, 0);   try {    mMessenger.send(msg);   } catch (RemoteException e) {    e.printStackTrace();   }   break;  case R.id.Button01:   msg = Message.obtain(null, 1, 0, 0);   try {    mMessenger.send(msg);   } catch (RemoteException e) {    e.printStackTrace();   }   break;  default:   break;  } }}