Bluetooth creates socket but blocks at connect() ANDROID

Question

I am using code from the Google Bluetooth Chat Example to set up a bluetooth listening server. I want the app to listen always for an incoming connection. When the app sees a connection request it will accept the connection, read in the string that the remote device will send, and then respond by sending a file.

The problem is that the app never accepts the connection. It blocks at socket = mmServerSocket.accept(); and never moves on. See the code below after the line if(D) System.out.println("Waiting to connect************"); To test it I start the activity that starts the thread and then attempt to connect with my laptop and send a file. When I do this the overall Android bluetooth manager sees the file and downloads it effectively bypassing my Android device. Is this the only way to test it? I cant figure out if its a testing or coding problem.

private class AcceptThread extends Thread {
    // The local server socket
    private final BluetoothServerSocket mmServerSocket;

    public AcceptThread() {
        BluetoothServerSocket tmp = null;

        // Create a new listening server socket
        try {
            tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
        } catch (IOException e) {
            Log.e(TAG, "listen() failed", e);
        }
        mmServerSocket = tmp;
    }

    public void run() {
        if (D) Log.d(TAG, "BEGIN mAcceptThread" + this);
        setName("AcceptThread");
        BluetoothSocket socket = null;

        // Listen to the server socket if we're not connected
        while (mState != STATE_CONNECTED) {
            try {
                // This is a blocking call and will only return on a
                // successful connection or an exception
                if(D) System.out.println("Waiting to connect************");
                socket = mmServerSocket.accept();
                if(D) System.out.println("We have accepted connection and are connected***************");
            } catch (IOException e) {
                Log.e(TAG, "accept() failed", e);
                break;
            }

            // If a connection was accepted
            if (socket != null) {
                synchronized (BluetoothServer.this) {
                    switch (mState) {
                    case STATE_LISTEN:
                    case STATE_CONNECTING:
                        // Situation normal. Start the connected thread.
                        connected(socket, socket.getRemoteDevice());
                        break;
                    case STATE_NONE:
                    case STATE_CONNECTED:
                        // Either not ready or already connected. Terminate new socket.
                        try {
                            socket.close();
                        } catch (IOException e) {
                            Log.e(TAG, "Could not close unwanted socket", e);
                        }
                        break;
                    }
                }
            }
        }
        if (D) Log.i(TAG, "END mAcceptThread");
    }

Answer 1

Hi, check if your client side is looking for same UUID as MY_UUID. You may want to change the UUID to generic UUID for RFCOMM.

private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");