记录一下Messenger的使用

服务端

1. 创建Messenger对象，传入Handler，在Handler中处理消息

public class MessengerService extends Service {
    private static final String TAG = MessengerService.class.getSimpleName();

    private final Messenger mMessenger = new Messenger(new MessengerHandler());

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return mMessenger.getBinder();
    }

    private static class MessengerHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case Constants.MSG_FROM_CLIENT:
                    String str = "receive msg from Client: " + msg.getData().getString("msg");
                    Log.i(TAG, str);
                    Messenger messenger = msg.replyTo;
                    Bundle bundle = new Bundle();
                    bundle.putString("reply", "客户1号你好，我是服务器");
                    msg.what = Constants.MSG_FROM_SERVICE;
                    msg.setData(bundle);
                    try {
                        messenger.send(msg);
                    } catch (RemoteException e) {
                        e.printStackTrace();
                    }
                    break;
            }
        }
    }
}

2.注册Service

<service android:name=".messenger.MessengerService"
            android:exported="true"/>

客户端

绑定服务端的Service，绑定成功后，根据服务端返回的binder对象创建Messenger对象，并向服务器发送消息。

public class MessengerActivity extends AppCompatActivity implements View.OnClickListener {
    private static final String TAG = MessengerActivity.class.getSimpleName();

    private TextView textView;
    private Button btnConnectService;
    private Messenger mService;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_messenger);
        textView = findViewById(R.id.tv_output);
        btnConnectService = findViewById(R.id.btnConnectService);
        btnConnectService.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btnConnectService:
                Intent intent = new Intent();
                intent.setComponent(new ComponentName("com.zxp.ipcserver","com.zxp.ipcserver.messenger.MessengerService"));
                bindService(intent,mServiceConnection, Context.BIND_AUTO_CREATE);
                break;
        }
    }


    private ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.d(TAG, "11111111111");
            mService = new Messenger(service);
            Message msg = Message.obtain(null, Constants.MSG_FROM_CLIENT);
            Bundle data = new Bundle();
            data.putString("msg", "嗨，我是客户1号.");
            textView.append("\n SEND:"+"嗨，我是客户1号.");

            msg.setData(data);
            msg.replyTo = getReplyMessenger;
            try {
                mService.send(msg);
            } catch (RemoteException e) {
                e.printStackTrace();
            }

        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
        }
    };

    private Messenger getReplyMessenger = new Messenger(new MessengerHandler());

    private class MessengerHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case Constants.MSG_FROM_SERVICE:
                    String str = "receive msg from Service:"+msg.getData().getString("reply");
                    Log.i(TAG, str);
                    textView.append("\n RECEIVE:"+msg.getData().getString("reply"));
                    break;
            }
        }
    }
}