Android 跨进程通Messenger(简单易懂)
不需要AIDL也不需要复杂的ContentProvider,也不需要SharedPreferences或者共享存储文件!
只需要简单易懂的Messenger,它也称为信使,通过它可以在不同进程中传递message对象,在message中放入我们需要传递的数据你就可以实现跨进程通讯和传递数据。废话不多说,直接上代码。
首先是服务端:
public class Ser extends Service{ @Override public IBinder onBind(Intent intent) { return messenger.getBinder(); } @Override public int onStartCommand(Intent intent, int flags, int startId) { // TODO Auto-generated method stub Log.i("Service", "onStartCommand()"); return super.onStartCommand(intent, flags, startId); } public Messenger messenger = new Messenger(new MyHandler()); public class MyHandler extends Handler{ @Override public 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,你的消息我已经收到,稍后回复你!"); message.setData(bundle); try { messenger.send(message); } catch (RemoteException e) { e.printStackTrace(); } super.handleMessage(msg); } }
我们在服务端操作了并不多,仅仅是实例化了一个Messenger,并且创建了一个handler用来接收客户端发送过来的消息
接下来看客户端:
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); @Override public IBinder onBind(Intent intent) { return null; } @Override public 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); } @Override public void onDestroy() { super.onDestroy(); unbindService(mBindService); } private ServiceConnection mBindService = new ServiceConnection(){ @Override public 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(); } } @Override public void onServiceDisconnected(ComponentName name) { // TODO Auto-generated method stub } }; }
同样客户端也需要一个handler来接收服务端返回的消息,还有很关键的一点
当客户端发送消息的时候,需要把接收服务端回复的Messenger通过Message的
replyTo参数传递给服务端,否则会报NullPointerException。然后我们在看下log
"hello this is client!" 这是客户端发给服务端的,证明服务端已经收到!
"嗯,你的消息我已经收到,稍后回复你!" 这是服务端返回给客户端的,证明客户端也收到了,并且还是实时通讯哦,到此我们的跨进程传递数据通讯完整结束啦,是不是很简单!
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