Android蓝牙RFCOMM无法接收字符串

Question

我试图在两个Android设备之间交换字符串。我能够建立RFCOMM连接并发送字符串。但我的APP无法收到它。经过几天的追踪和错误，并在网上搜索，我希望有人可以帮助我：

到目前为止我的代码：

public class MainActivity extends AppCompatActivity {
BluetoothAdapter bluetoothAdapter;
protected static final int SUCCESS_CONNECT = 0;
protected static final int MESSAGE_READ = 1;


Handler mHandler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        Log.i("MAC", "in handler");
        super.handleMessage(msg);
        switch(msg.what){
            case SUCCESS_CONNECT:
                // DO something
                ConnectedThread connectedThread = new ConnectedThread((BluetoothSocket)msg.obj);
                connectedThread.run();
                Toast.makeText(getApplicationContext(), "CONNECT", Toast.LENGTH_LONG).show();
                String s = "successfully connected";
                connectedThread.write(s.getBytes());
                Log.i("MAC", "connected");

                break;
            case MESSAGE_READ:
                byte[] readBuf = (byte[])msg.obj;
                String string = new String(readBuf);
                Toast.makeText(getApplicationContext(), string, Toast.LENGTH_LONG).show();
                break;
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED);
    registerReceiver(mReceiver,filter);
}


private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        final String action = intent.getAction();

        if (action.equals(BluetoothDevice.ACTION_ACL_CONNECTED)){
            BluetoothDevice device = intent
                    .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

            Log.i("MAC","Connect to : " +device.getAddress());
            ConnectingThread ct = new ConnectingThread(device);
            ct.start();
        }
    }
};

private class ConnectingThread extends Thread {
    private final BluetoothSocket bluetoothSocket;
    private final BluetoothDevice bluetoothDevice;

    public ConnectingThread(BluetoothDevice device) {

        BluetoothSocket temp = null;
        bluetoothDevice = device;

        // Get a BluetoothSocket to connect with the given BluetoothDevice
        try {
            temp = bluetoothDevice.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        bluetoothSocket = temp;
    }

    public void run() {
        // Cancel any discovery as it will slow down the connection
        bluetoothAdapter.cancelDiscovery();

        try {
            // This will block until it succeeds in connecting to the device
            // through the bluetoothSocket or throws an exception
            bluetoothSocket.connect();
        } catch (IOException connectException) {
            connectException.printStackTrace();
            try {
                bluetoothSocket.close();
            } catch (IOException closeException) {
                closeException.printStackTrace();
            }
        }

        // Code to manage the connection in a separate thread
        mHandler.obtainMessage(SUCCESS_CONNECT, bluetoothSocket).sendToTarget();
    /*
        manageBluetoothConnection(bluetoothSocket);
    */
    }

    // Cancel an open connection and terminate the thread
    public void cancel() {
        try {
            bluetoothSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
private class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final InputStream mmInStream;
    private final OutputStream mmOutStream;

    public ConnectedThread(BluetoothSocket socket) {
        mmSocket = socket;
        InputStream tmpIn = null;
        OutputStream tmpOut = null;

        // Get the input and output streams, using temp objects because
        // member streams are final
        try {

            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        } catch (IOException e) {}

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }


    public void run() {

        byte[] buffer;  // buffer store for the stream
        int bytes; // bytes returned from read()

        // Keep listening to the InputStream until an exception occurs
        while (true) {
            try {

                // Read from the InputStream
                buffer = new byte[1024];
                bytes = mmInStream.read(buffer);
                // Send the obtained bytes to the UI activity

                mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {

                break;

            }
        }
    }

    /* Call this from the main activity to send data to the remote device */
    public void write(byte[] bytes) {
        try {
            mmOutStream.write(bytes);
        } catch (IOException e) { }
    }

    /* Call this from the main activity to shutdown the connection */
    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) { }
    }
}

}