try to create separate threads for each connection - I had a similar issue and creating a new thread for each connection solved it nicely. By the way I even create a new thread to establish the connection - so establishing the connection does not block the UI. Got this from the BT sample code...
to create a new thread to establish a connection:
mConnectBluetoothThread = new ConnectBluetoothThread(device);
mConnectBluetoothThread.start();
where ConnectBluetoothThread is defined like:
public ConnectBluetoothThread(BluetoothDevice device) {
if (DEBUG)
Log.i(this.getClass().getSimpleName(),
this.getClass().getName()
+ " ->"
+ Thread.currentThread().getStackTrace()[2]
.getMethodName());
mmDevice = device;
BluetoothSocket tmp = null;
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.e(this.getClass().getSimpleName(), "create() failed", e);
}
mmSocket = tmp;
}
public void run() {
if (DEBUG)
Log.i(this.getClass().getSimpleName(),
this.getClass().getName()
+ " ->"
+ Thread.currentThread().getStackTrace()[2]
.getMethodName());
// TODO
setName("ConnectThread");
// Always cancel discovery because it will slow down a connection
mBluetoothAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
} catch (IOException e) {
connectionFailed();
// Close the socket
try {
mmSocket.close();
} catch (IOException e2) {
Log.e(this.getClass().getSimpleName(),
"unable to close() socket during connection failure",
e2);
}
return;
}
// Reset the ConnectThread because we're done
synchronized (InterBT.this) {
mConnectBluetoothThread = null;
}
// Start the connected thread
connected(mmSocket, mmDevice);
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(this.getClass().getSimpleName(),
"close() of connect socket failed", e);
}
}
}
public synchronized void connected(BluetoothSocket socket,
BluetoothDevice device) {
if (DEBUG)
Log.d(this.getClass().getSimpleName(), "connected");
// Cancel the thread that completed the connection
if (mConnectBluetoothThread != null) {
mConnectBluetoothThread.cancel();
mConnectBluetoothThread = null;
}
// Cancel any thread currently running a connection
if (mConnectedBluetoothThread != null) {
mConnectedBluetoothThread.cancel();
mConnectedBluetoothThread = null;
}
// Cancel the accept thread because we only want to connect to one
// device
// if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread =
// null;}
// Start the thread to manage the connection and perform transmissions
mConnectedBluetoothThread = new ConnectionThreadBT(socket);
mConnectedBluetoothThread.start();
setState(STATE_CONNECTED);
}
and also create a new class ConnectionThreadBT that handles the connection to read and write:
public class ConnectionThreadBT extends ConnectionThreadBase {
private static final boolean DEBUG = true;
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
byte[] responseBuffer = new byte[4096 * 4];
int responseBufferLen = 0;
public ConnectionThreadBT(BluetoothSocket socket) {
if (DEBUG)
Log.i(this.getClass().getSimpleName(),
this.getClass().getName()
+ " ->"
+ Thread.currentThread().getStackTrace()[2]
.getMethodName());
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(this.getClass().getSimpleName(), "temp sockets not created",
e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
if (DEBUG)
Log.i(this.getClass().getSimpleName(),
this.getClass().getName()
+ " ->"
+ Thread.currentThread().getStackTrace()[2]
.getMethodName());
//we have successfully connected to BT
//now inform UI
Home_Screen.sendMessageToHomeScreen(
Home_Screen.MESSAGE_INTERBT_CONNECTION_TESTED,
Home_Screen.CONNECTION_SUCCESS, true);
}
and then to write just call this method which is also defined within ConnectionThreadBT
public void sendMsg(MyBuffer buffer){
try {
mmOutStream.write(buffer);
mmOutStream.flush();
successfullyWritten = true;
} catch (IOException e) {
Log.e(this.getClass().getSimpleName(),
"Exception during write", e);
successfullyWritten = false;
}
to read either do the same or start a monitoring loop in the run method which keeps reading as long as the connectedThread is alive and reports back any read information through a handler similar to the UI screen update
