Android 使用Massenger及Handler进行通信

1.客户端service

public class MessageService extends Service {

    private static final int MSG_SET_VALUE = 0x110;
    private Handler mHandler = new Handler() {
        public void handleMessage(Message msgFromClient) {
            // 返回给客户的信息
            Message msgToClient = Message.obtain(msgFromClient);
            switch (msgFromClient.what) {
            // msg 客户端传来的消息
            case MSG_SET_VALUE:
                try {
                    msgToClient.what = MSG_SET_VALUE;
                    SystemClock.sleep(2000);

                    msgToClient.arg2 = msgFromClient.arg1 + msgFromClient.arg2;
                    //msgFromClient.replyTo.send(msgToClient);

                    //得到客户端的信使对象，并向它发送消息 
                    cMessenger = msgFromClient.replyTo;
                    cMessenger.send(msgToClient);

                } catch (RemoteException e) {
                    e.printStackTrace();
                }

                break;

            default:
                break;
            }
        }
    };
    private Messenger mMessager = new Messenger(mHandler);
    private Messenger cMessenger;

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

    @Override
    public void onDestroy() {
        cMessenger = null;
        super.onDestroy();
    }
}

2.服务器端service

public class MessageService extends Service {

    private static final int MSG_SET_VALUE = 0x110;
    private Handler mHandler = new Handler() {
        public void handleMessage(Message msgFromClient) {
            // 返回给客户的信息
            Message msgToClient = Message.obtain(msgFromClient);
            switch (msgFromClient.what) {
            // msg 客户端传来的消息
            case MSG_SET_VALUE:
                try {
                    msgToClient.what = MSG_SET_VALUE;
                    SystemClock.sleep(2000);

                    msgToClient.arg2 = msgFromClient.arg1 + msgFromClient.arg2;
                    //msgFromClient.replyTo.send(msgToClient);

                    //得到客户端的信使对象，并向它发送消息 
                    cMessenger = msgFromClient.replyTo;
                    cMessenger.send(msgToClient);

                } catch (RemoteException e) {
                    e.printStackTrace();
                }

                break;

            default:
                break;
            }
        }
    };
    private Messenger mMessager = new Messenger(mHandler);
    private Messenger cMessenger;

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

    @Override
    public void onDestroy() {
        cMessenger = null;
        super.onDestroy();
    }
}

3.客户端使用

public class MainActivity extends Activity {
    private static final int MSG_SET_VALUE = 0x110;
    private TextView mTVStatus; // 连接状态
    private LinearLayout mLLContainer;// 用来添加接收到服务器返回的信息
    private Messenger mService; // 客户端信使
    private boolean isConnecting; // 是否连接
    private Handler mHandler = new Handler() {
        public void handleMessage(Message msgFromServer) {
            switch (msgFromServer.what) {
            case MSG_SET_VALUE:
                TextView tv = (TextView) findViewById(msgFromServer.arg1);
                tv.setText(tv.getText() + "==>" + msgFromServer.arg2);
                break;
            }
            super.handleMessage(msgFromServer);
        };
    };
    private Messenger mMessenger = new Messenger(mHandler);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTVStatus = (TextView) findViewById(R.id.tv_status);
        mLLContainer = (LinearLayout) findViewById(R.id.ll_container);
    }

    int i = 0;
    public void send(View view){
        try {
            int a = i++;
            int b = (int) (Math.random() * 100);

            //创建一个tv,添加到LinearLayout中
            TextView tv = new TextView(MainActivity.this);
            tv.setText(a + " + " + b + " = caculating ...");
            tv.setId(a);

            mLLContainer.addView(tv);

            Message msgFromClient = Message.obtain(null, MSG_SET_VALUE, a, b);
            msgFromClient.replyTo = mMessenger;
            if (isConnecting) {
                //往服务端发送消息
                mService.send(msgFromClient);
            }
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

    public void bind(View view) {
        Intent service = new Intent();
        service.setAction("android.intent.action.MESSAGE_SERVER");
        bindService(service, conn, Context.BIND_AUTO_CREATE);
    }

    private ServiceConnection conn = new ServiceConnection() {
        @Override
        public void onServiceDisconnected(ComponentName name) {
            mService = null;
            isConnecting = false;
            mTVStatus.setText("已断开连接！");
        }

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            mService = new Messenger(service);
            isConnecting = true;
            mTVStatus.setText("连接成功！");
        }
    };

    public void unbind(View view) {
        unbindService(conn);
        conn = null;
    }

    @Override
    protected void onDestroy() {
        unbindService(conn);
        conn = null;
        super.onDestroy();
    }
}