无法连接蓝牙设备

Question

I am trying to connect bluetooth device and want to send data to that device and also want to receive data from that device.

To achieve this I follow android developer bluetooth document but seems I unable to connect another device because while connecting it's throwing following exception.

09-13 13:27:56.913: I/BluetoothConnect(2980): Connect exception:-java.io.IOException: [JSR82] connect: Connection is not created (failed or aborted).    

Steps which I follow.

1. Enabling Bluetooth

    Intent turnOnIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(turnOnIntent, REQUEST_ENABLE_BT); 

2. Getting Bluetooth Paired Device

    Set<BluetoothDevice> bondSet = myBluetoothAdapter.getBondedDevices(); ArrayList<HashMap<String, String>> bondedhDevicesList = new ArrayList<HashMap<String, String>>(); for (Iterator<BluetoothDevice> it = bondSet.iterator(); it.hasNext();) { BluetoothDevice bluetoothDevice = (BluetoothDevice) it.next(); HashMap<String, String> map = new HashMap<String, String>(); map.put("name", bluetoothDevice.getName()); map.put("address", bluetoothDevice.getAddress()); bondedhDevicesList.add(map); } 

3. Getting UUID of device

     bluetoothDevice = myBluetoothAdapter.getRemoteDevice(address); // min api 15 !!! Method m; try { m = bluetoothDevice.getClass(). getMethod("fetchUuidsWithSdp", (Class[]) null); m.invoke(bluetoothDevice, (Object[]) null ); } catch (NoSuchMethodException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } 

4. Connecting to device

   private static final UUID MY_UUID = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");

    public ConnectThread(BluetoothDevice device, String uuid, BluetoothAdapter mBluetoothAdapter) {
    // Use a temporary object that is later assigned to mmSocket,
    // because mmSocket is final
    BluetoothSocket tmp = null;
    this.mBluetoothAdapter = mBluetoothAdapter;
    mmDevice = device;

    Method m;
    try {
        mBluetoothAdapter.cancelDiscovery();
        mmSocket = device.createInsecureRfcommSocketToServiceRecord(MY_UUID);
        m = device.getClass().getMethod("createInsecureRfcommSocket", new Class[] {int.class});
        mmSocket = (BluetoothSocket) m.invoke(device, 1);   
    } catch (IOException |  IllegalArgumentException | IllegalAccessException | InvocationTargetException | NoSuchMethodException  e) {
        // TODO Auto-generated catch block
        Log.i("BluetoothConnect", e.toString());
        e.printStackTrace();
     }

     //mBluetoothAdapter.cancelDiscovery();
     //socket.connect();
    } 
    public void run() {
    // Cancel discovery because it will slow down the connection
    mBluetoothAdapter.cancelDiscovery(); 
    try {
        // Connect the device through the socket. This will block
        // until it succeeds or throws an exception
        mmSocket.connect();
        Constants.globalSocket = mmSocket;
    } catch (IOException connectException) {
        // Unable to connect; close the socket and get out
        Log.i("BluetoothConnect", "Connect exception:-"+connectException.toString());
        try {
            mmSocket.close();
        } catch (IOException closeException) { 
            Log.i("BluetoothConnect", "close exception:-"+closeException.toString());
        }
        return;
    }         
}

But while connecting then i am getting that exception.
5. Writing to device.

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 = new byte[1024];  // 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
            bytes = mmInStream.read(buffer);

            // Send the obtained bytes to the UI activity
            CreatePacket.mHandler.obtainMessage(MESSAGE_READ , bytes, -1, buffer)
                    .sendToTarget();
        } catch (IOException e) {
            Log.i("ConnectedThread", "while receiving data:-"+e.toString());
            break;
        }
      }
     }       


  public void write(byte[] bytes) {
    Log.i("ConnectedThread", "data while writing:-"+bytes.toString());
    try {
        mmOutStream.write(bytes);
    } catch (IOException e) {
        Log.i("ConnectedThread", "while writing data to bluetooth:-"+e.toString());
    }
  }    

If I still try to write then data then I am getting following exception.

Please give me any hint or reference.

09-13 13:48:55.079: I/ConnectedThread(2980): while writing data to bluetooth:-java.io.IOException: socket closed

I am stuck on this from last three day but still not getting any solution.

Answer 1

The best way is to refer the sample chat application provided by the Android. That has covered all necessary tasks like list out available devices, establish connection, send data and receive, etc. U can get that and refer. https://android.googlesource.com/platform/development/+/eclair-passion-release/samples/BluetoothChat

Answer 2

Here is a sample code which I am using to connect to my Bluetooth module..

public class OpenBluetoothPort extends AsyncTask<String, Void, BluetoothSocket> {

    private final UUID SPP_UUID = UUID
            .fromString("00001101-0000-1000-8000-00805F9B34FB");
    private BluetoothAdapter mBluetoothAdapter;
    private OnBluetoothPortOpened mCallback;
    private BluetoothSocket mBSocket;

    public interface OnBluetoothPortOpened {
        public void OnBluetoothConnectionSuccess(BluetoothSocket socket);
        public void OnBluetoothConnectionFailed();
    }

    public OpenBluetoothPort(Context context, OnBluetoothPortOpened callback) {
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        mCallback = callback;
    }

    @Override
    protected BluetoothSocket doInBackground(String... params) {
        if(mBluetoothAdapter.isEnabled()) {
            try {
                for(BluetoothDevice bt: mBluetoothAdapter.getBondedDevices()) {
                    if(bt.getName().equalsIgnoreCase(params[0])) {
                        BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(bt.getAddress());
                        mBluetoothAdapter.cancelDiscovery();

                        mBSocket = device.createRfcommSocketToServiceRecord(SPP_UUID);
                        mBSocket.connect();
                        return mBSocket;
                    }
                }
            } catch(IOException e) {
                if(mBSocket != null) {
                    try {
                        mBSocket.close();
                    } catch (IOException e1) {
                        Log.i("Bluetooth Close Exception","Error in closing bluetooth in OpenBluetoothPort.class");
                        e1.printStackTrace();
                    }
                    mBSocket = null;
                }
                Log.i("Bluetooth Connect Exception","Error in connecting in OpenBluetoothPort.class");
                e.printStackTrace();
                return null;
            }
        } 
        return null;
    }

    @Override
    protected void onPostExecute(BluetoothSocket result) {
        super.onPostExecute(result);
        if(result != null && result.isConnected()) {
            mCallback.OnBluetoothConnectionSuccess(result);
        } else {
            mCallback.OnBluetoothConnectionFailed();
        }
    }



}