Connecting BAFX OBD-II Adapter to Modified BluetoothChat App not working

Question

I bought a BAFX OBD-II bluetooth adapter. I'm currently attempting to modify the sample BluetoothChat App to communicate with the adapter. However, whenever I attempt to connect to it the app says "Unable to connect". Pairing outside the app works but not within the app. The strange thing is that the device works with both Torque and DashCommand. I've tried changing the UUID to SPP but that also didn't work. I'm running the app on a Nexus 7 with Android 4.2.2. Please help.

Here's the code for the first part of the BluetoothChat Activity

public class BluetoothChat<ImageView> extends Activity {
// Debugging
private static final String TAG = "BluetoothChat";
private static final boolean D = true;

// Message types sent from the BluetoothChatService Handler
public static final int MESSAGE_STATE_CHANGE = 1;
public static final int MESSAGE_READ = 2;
public static final int MESSAGE_WRITE = 3;
public static final int MESSAGE_DEVICE_NAME = 4;
public static final int MESSAGE_TOAST = 5;

// Key names received from the BluetoothChatService Handler
public static final String DEVICE_NAME = "device_name";
public static final String TOAST = "toast";

// Intent request codes
private static final int REQUEST_CONNECT_DEVICE_SECURE = 1;
private static final int REQUEST_CONNECT_DEVICE_INSECURE = 2;
private static final int REQUEST_ENABLE_BT = 3;

// Layout Views
private ListView mConversationView;
private EditText mOutEditText;
private Button mSendButton;

// Name of the connected device
private String mConnectedDeviceName = null;
// Array adapter for the conversation thread
private ArrayAdapter<String> mConversationArrayAdapter;
// String buffer for outgoing messages
private StringBuffer mOutStringBuffer;
// Local Bluetooth adapter
private BluetoothAdapter mBluetoothAdapter = null;
// Member object for the chat services
private BluetoothChatService mChatService = null;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if(D) Log.e(TAG, "+++ ON CREATE +++");

    // Set up the window layout
    setContentView(R.layout.main);

    // Get local Bluetooth adapter
    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

    // If the adapter is null, then Bluetooth is not supported
    if (mBluetoothAdapter == null) {
        Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();
        finish();
        return;
    }
}

@Override
public void onStart() {
    super.onStart();
    if(D) Log.e(TAG, "++ ON START ++");

    // If BT is not on, request that it be enabled.
    // setupChat() will then be called during onActivityResult
    if (!mBluetoothAdapter.isEnabled()) {
        Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
    // Otherwise, setup the chat session
    } else {
        if (mChatService == null) setupChat();
    }
}

@Override
public synchronized void onResume() {
    super.onResume();
    if(D) Log.e(TAG, "+ ON RESUME +");

    // Performing this check in onResume() covers the case in which BT was
    // not enabled during onStart(), so we were paused to enable it...
    // onResume() will be called when ACTION_REQUEST_ENABLE activity returns.
    if (mChatService != null) {
        // Only if the state is STATE_NONE, do we know that we haven't started already
        if (mChatService.getState() == BluetoothChatService.STATE_NONE) {
          // Start the Bluetooth chat services
          mChatService.start();
        }
    }
}

//keep track of current PID number
int message_number = 1;

private void setupChat() {
    Log.d(TAG, "setupChat()");

    // Initialize the array adapter for the conversation thread
    mConversationArrayAdapter = new ArrayAdapter<String>(this, R.layout.message);
    mConversationView = (ListView) findViewById(R.id.in);
    mConversationView.setAdapter(mConversationArrayAdapter);

    // Initialize the compose field with a listener for the return key
    //mOutEditText = (EditText) findViewById(R.id.edit_text_out);
    //mOutEditText.setOnEditorActionListener(mWriteListener);

    // Initialize the send button with a listener that for click events
    /*mSendButton = (Button) findViewById(R.id.button_send);
    mSendButton.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            // Send a message using content of the edit text widget
            TextView view = (TextView) findViewById(R.id.edit_text_out);
            String message = view.getText().toString();
            sendMessage(message + '\r');
        }
    });*/

    // Initialize the BluetoothChatService to perform bluetooth connections
    mChatService = new BluetoothChatService(this, mHandler);

    // Initialize the buffer for outgoing messages
    mOutStringBuffer = new StringBuffer("");

    //---Get Vehicle Data Button---
    final ToggleButton getDataButton = (ToggleButton) findViewById(R.id.toggleButton1);
    getDataButton.setOnClickListener(new View.OnClickListener() 
    {

        public void onClick(View v) {

            if(getDataButton.isChecked()) {
                startTransmission();
            }
            else {
                message_number = 0;
            }

        }
    });


    //---Clear Trouble Codes Button---
    Button getCodesButton = (Button) findViewById(R.id.button2);
    getCodesButton.setOnClickListener(new View.OnClickListener() 
    {

        public void onClick(View v) {

            clearCodes();
        }
    });   

}

This is the code for the BluetoothChatService

public class BluetoothChatService {
// Debugging
private static final String TAG = "BluetoothChatService";
private static final boolean D = true;

// Name for the SDP record when creating server socket
private static final String NAME_SECURE = "BluetoothChatSecure";
private static final String NAME_INSECURE = "BluetoothChatInsecure";

// Unique UUID for this application
private static final UUID MY_UUID_SECURE =
    UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
private static final UUID MY_UUID_INSECURE =
    UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66");

// Member fields
private final BluetoothAdapter mAdapter;
private final Handler mHandler;
private AcceptThread mSecureAcceptThread;
private AcceptThread mInsecureAcceptThread;
private ConnectThread mConnectThread;
private ConnectedThread mConnectedThread;
private int mState;

// Constants that indicate the current connection state
public static final int STATE_NONE = 0;       // we're doing nothing
public static final int STATE_LISTEN = 1;     // now listening for incoming connections
public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
public static final int STATE_CONNECTED = 3;  // now connected to a remote device

/**
 * Constructor. Prepares a new BluetoothChat session.
 * @param context  The UI Activity Context
 * @param handler  A Handler to send messages back to the UI Activity
 */
public BluetoothChatService(Context context, Handler handler) {
    mAdapter = BluetoothAdapter.getDefaultAdapter();
    mState = STATE_NONE;
    mHandler = handler;
}

/**
 * Set the current state of the chat connection
 * @param state  An integer defining the current connection state
 */
private synchronized void setState(int state) {
    if (D) Log.d(TAG, "setState() " + mState + " -> " + state);
    mState = state;

    // Give the new state to the Handler so the UI Activity can update
    mHandler.obtainMessage(BluetoothChat.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
}

/**
 * Return the current connection state. */
public synchronized int getState() {
    return mState;
}

/**
 * Start the chat service. Specifically start AcceptThread to begin a
 * session in listening (server) mode. Called by the Activity onResume() */
public synchronized void start() {
    if (D) Log.d(TAG, "start");

    // Cancel any thread attempting to make a connection
    if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

    // Cancel any thread currently running a connection
    if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

    setState(STATE_LISTEN);

    // Start the thread to listen on a BluetoothServerSocket
    if (mSecureAcceptThread == null) {
        mSecureAcceptThread = new AcceptThread(true);
        mSecureAcceptThread.start();
    }
    if (mInsecureAcceptThread == null) {
        mInsecureAcceptThread = new AcceptThread(false);
        mInsecureAcceptThread.start();
    }
}

/**
 * Start the ConnectThread to initiate a connection to a remote device.
 * @param device  The BluetoothDevice to connect
 * @param secure Socket Security type - Secure (true) , Insecure (false)
 */
public synchronized void connect(BluetoothDevice device, boolean secure) {
    if (D) Log.d(TAG, "connect to: " + device);

    // Cancel any thread attempting to make a connection
    if (mState == STATE_CONNECTING) {
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
    }

    // Cancel any thread currently running a connection
    if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

    // Start the thread to connect with the given device
    mConnectThread = new ConnectThread(device, secure);
    mConnectThread.start();
    setState(STATE_CONNECTING);
}

/**
 * Start the ConnectedThread to begin managing a Bluetooth connection
 * @param socket  The BluetoothSocket on which the connection was made
 * @param device  The BluetoothDevice that has been connected
 */
public synchronized void connected(BluetoothSocket socket, BluetoothDevice
        device, final String socketType) {
    if (D) Log.d(TAG, "connected, Socket Type:" + socketType);

    // Cancel the thread that completed the connection
    if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

    // Cancel any thread currently running a connection
    if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

    // Cancel the accept thread because we only want to connect to one device
    if (mSecureAcceptThread != null) {
        mSecureAcceptThread.cancel();
        mSecureAcceptThread = null;
    }
    if (mInsecureAcceptThread != null) {
        mInsecureAcceptThread.cancel();
        mInsecureAcceptThread = null;
    }

    // Start the thread to manage the connection and perform transmissions
    mConnectedThread = new ConnectedThread(socket, socketType);
    mConnectedThread.start();

    // Send the name of the connected device back to the UI Activity
    Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_DEVICE_NAME);
    Bundle bundle = new Bundle();
    bundle.putString(BluetoothChat.DEVICE_NAME, device.getName());
    msg.setData(bundle);
    mHandler.sendMessage(msg);

    setState(STATE_CONNECTED);
}

/**
 * Stop all threads
 */
public synchronized void stop() {
    if (D) Log.d(TAG, "stop");

    if (mConnectThread != null) {
        mConnectThread.cancel();
        mConnectThread = null;
    }

    if (mConnectedThread != null) {
        mConnectedThread.cancel();
        mConnectedThread = null;
    }

    if (mSecureAcceptThread != null) {
        mSecureAcceptThread.cancel();
        mSecureAcceptThread = null;
    }

    if (mInsecureAcceptThread != null) {
        mInsecureAcceptThread.cancel();
        mInsecureAcceptThread = null;
    }
    setState(STATE_NONE);
}

/**
 * Write to the ConnectedThread in an unsynchronized manner
 * @param out The bytes to write
 * @see ConnectedThread#write(byte[])
 */
public void write(byte[] out) {
    // Create temporary object
    ConnectedThread r;
    // Synchronize a copy of the ConnectedThread
    synchronized (this) {
        if (mState != STATE_CONNECTED) return;
        r = mConnectedThread;
    }
    // Perform the write unsynchronized
    r.write(out);
}

/**
 * Indicate that the connection attempt failed and notify the UI Activity.
 */
private void connectionFailed() {
    // Send a failure message back to the Activity
    Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST);
    Bundle bundle = new Bundle();
    bundle.putString(BluetoothChat.TOAST, "Unable to connect device");
    msg.setData(bundle);
    mHandler.sendMessage(msg);

    // Start the service over to restart listening mode
    BluetoothChatService.this.start();
}

/**
 * Indicate that the connection was lost and notify the UI Activity.
 */
private void connectionLost() {
    // Send a failure message back to the Activity
    Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST);
    Bundle bundle = new Bundle();
    bundle.putString(BluetoothChat.TOAST, "Device connection was lost");
    msg.setData(bundle);
    mHandler.sendMessage(msg);

    // Start the service over to restart listening mode
    BluetoothChatService.this.start();
}

/**
 * This thread runs while listening for incoming connections. It behaves
 * like a server-side client. It runs until a connection is accepted
 * (or until cancelled).
 */
private class AcceptThread extends Thread {
    // The local server socket
    private final BluetoothServerSocket mmServerSocket;
    private String mSocketType;

    public AcceptThread(boolean secure) {
        BluetoothServerSocket tmp = null;
        mSocketType = secure ? "Secure":"Insecure";

        // Create a new listening server socket
        try {
            if (secure) {
                tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE,
                    MY_UUID_SECURE);
            } else {
                tmp = mAdapter.listenUsingInsecureRfcommWithServiceRecord(
                        NAME_INSECURE, MY_UUID_INSECURE);
            }
        } catch (IOException e) {
            Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e);
        }
        mmServerSocket = tmp;
    }

    public void run() {
        if (D) Log.d(TAG, "Socket Type: " + mSocketType +
                "BEGIN mAcceptThread" + this);
        setName("AcceptThread" + mSocketType);

        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
                socket = mmServerSocket.accept();
            } catch (IOException e) {
                Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e);
                break;
            }

            // If a connection was accepted
            if (socket != null) {
                synchronized (BluetoothChatService.this) {
                    switch (mState) {
                    case STATE_LISTEN:
                    case STATE_CONNECTING:
                        // Situation normal. Start the connected thread.
                        connected(socket, socket.getRemoteDevice(),
                                mSocketType);
                        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, socket Type: " + mSocketType);

    }

    public void cancel() {
        if (D) Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this);
        try {
            mmServerSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e);
        }
    }
}


/**
 * This thread runs while attempting to make an outgoing connection
 * with a device. It runs straight through; the connection either
 * succeeds or fails.
 */
private class ConnectThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final BluetoothDevice mmDevice;
    private String mSocketType;



    public ConnectThread(BluetoothDevice device, boolean secure) {
        mmDevice = device;
        BluetoothSocket tmp = null;
        mSocketType = secure ? "Secure" : "Insecure";

        //Modified to work with SPP Devices
        final UUID SPP_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

        // Get a BluetoothSocket for a connection with the
        // given BluetoothDevice
        try {
            if (secure) {
                //tmp = device.createRfcommSocketToServiceRecord(
                //        MY_UUID_SECURE);

                tmp = device.createRfcommSocketToServiceRecord(SPP_UUID);


            } else {
                //tmp = device.createInsecureRfcommSocketToServiceRecord(
                //        MY_UUID_INSECURE);
                tmp = device.createRfcommSocketToServiceRecord(SPP_UUID);

                //Method m = device.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
                //tmp = (BluetoothSocket) m.invoke(device, 1);
            }
        } catch (IOException e) {
            Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e);
        }
        mmSocket = tmp;
    }

    public void run() {
        Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType);
        setName("ConnectThread" + mSocketType);

        // Always cancel discovery because it will slow down a connection
        mAdapter.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) {
            // Close the socket
            try {
                mmSocket.close();
            } catch (IOException e2) {
                Log.e(TAG, "unable to close() " + mSocketType +
                        " socket during connection failure", e2);
            }
            connectionFailed();
            return;
        }

        // Reset the ConnectThread because we're done
        synchronized (BluetoothChatService.this) {
            mConnectThread = null;
        }

        // Start the connected thread
        connected(mmSocket, mmDevice, mSocketType);
    }

    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e);
        }
    }
}

/**
 * This thread runs during a connection with a remote device.
 * It handles all incoming and outgoing transmissions.
 */
private class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final InputStream mmInStream;
    private final OutputStream mmOutStream;

    public ConnectedThread(BluetoothSocket socket, String socketType) {
        Log.d(TAG, "create ConnectedThread: " + socketType);
        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(TAG, "temp sockets not created", e);
        }

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }

    public void run() {
        Log.i(TAG, "BEGIN mConnectedThread");
        byte[] buffer = new byte[1024];
        int bytes;

        // Keep listening to the InputStream while connected
        while (true) {
            try {
                // Read from the InputStream
                bytes = mmInStream.read(buffer);


                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                // Start the service over to restart listening mode
                BluetoothChatService.this.start();
                break;
            }
        }
    }

    /**
     * Write to the connected OutStream.
     * @param buffer  The bytes to write
     */
    public void write(byte[] buffer) {
        try {
            mmOutStream.write(buffer);

            // Share the sent message back to the UI Activity
            mHandler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer)
                    .sendToTarget();
        } catch (IOException e) {
            Log.e(TAG, "Exception during write", e);
        }
    }

    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "close() of connect socket failed", e);
        }
    }


}

}

I also realised after trying stuff out that the BluetoothChat sample app for 2.3.3 SDK worked when connecting to the device where the above code for 3.0 or higher failed. Any ideas why that is and how to solve it?

Answer 1

Finally figured this out. All I had to do was to downgrade my Nexus 7 from 4.2.2 to 4.1.2 and now it connects. Don't know what caused the problem though...maybe a bug.