I need to send string message from Raspberry PI to Android device. I am getting message first time only. After that it does not work at all. I am using PYTHON code in Raspberry PI. After first time, it is unable to search for a bluetooth device, which is running that UUID. However, if I restart Android application - again it works fine for first time. I am using AcceptThread as suggested here. I have not used ConnectThread or ConnectedThread in my application, as I need only incoming messages. Do I need to close something on Pause or Destroy. Or, do I need to do something which is not mentioned in that page?

Here is that code:

private UUID MY_UUID = UUID.fromString("1e0ca4ea-299d-4335-93eb-27fcfe7fa848");
private AcceptThread acceptThread;private class AcceptThread extends Thread {private final BluetoothServerSocket mmServerSocket;public AcceptThread() {// Use a temporary object that is later assigned to mmServerSocket,// because mmServerSocket is finalBluetoothServerSocket tmp = null;try {// MY_UUID is the app's UUID string, also used by the client codetmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord(TAG, MY_UUID);} catch (IOException e) { }mmServerSocket = tmp;}public void run() {BluetoothSocket socket = null;// Keep listening until exception occurs or a socket is returnedwhile (true) {try {socket = mmServerSocket.accept();} catch (IOException e) {break;}// If a connection was acceptedif (socket != null) {// Do work to manage the connection (in a separate thread)manageConnectedSocket(socket);try {mmServerSocket.close();}catch(IOException e){}break;}}}/** Will cancel the listening socket, and cause the thread to finish */public void cancel() {try {mmServerSocket.close();} catch (IOException e) { }}
}

I am not using PI message, just logging a string. As mentioned above, it works first time:

private void manageConnectedSocket(BluetoothSocket socket) {Log.i(TAG, "Hurray!! I am here");//acceptThread.cancel();
}

Here is the PYTHON code in Raspberry PI:

import sys
import bluetoothuuid = "1e0ca4ea-299d-4335-93eb-27fcfe7fa848"service_matches = bluetooth.find_service( uuid = uuid )if len(service_matches) == 0:print "couldn't find the BluetoothWithPi service"sys.exit(0)first_match = service_matches[0]
port = first_match["port"]
name = first_match["name"]
host = first_match["host"]print "connected to \"%s\" on %s" % (name, host)sock=bluetooth.BluetoothSocket( bluetooth.RFCOMM )
sock.connect((host, port))
sock.send("Hello from Raspberry PI!!")
sock.close()

First time it displays 'Connected to ...' message. Second time it displays 'Couldn't find...' message.

We just need to add some code into manageConnectedSocket block. Basically we need to cancel the acceptThread if not null and restart the service:

private void manageConnectedSocket(BluetoothSocket socket) {Log.i(TAG, "Hurray!! I am here");//if (acceptThread != null) {acceptThread.cancel();acceptThread = null;}//if (acceptThread == null) {acceptThread = new AcceptThread();acceptThread.start();}
}