android开发之使用Messenger实现service与activity交互

service与activity交互的方式有多种，这里说说使用Messenger来实现两者之间的交互。

Service程序

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;
            }
        }

    }
}

MainActivity.java

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;
        }
    }
}