How to keep Bluetooth connection background?

Yes, I found working solution for running Bluetooth background in android.Below is the code I have used in my android app.

public class BluetoothServices extends Service {private BluetoothAdapter mBluetoothAdapter;public static final String B_DEVICE = "MY DEVICE";public static final String B_UUID = "00001101-0000-1000-8000-00805f9b34fb";// 00000000-0000-1000-8000-00805f9b34fbpublic static final int STATE_NONE = 0;public static final int STATE_LISTEN = 1;public static final int STATE_CONNECTING = 2;public static final int STATE_CONNECTED = 3;private ConnectBtThread mConnectThread;private static ConnectedBtThread mConnectedThread;private static Handler mHandler = null;public static int mState = STATE_NONE;public static String deviceName;public static BluetoothDevice sDevice = null;public Vector<Byte> packData = new Vector<>(2048);//IBinder mIBinder = new LocalBinder();@Nullable@Overridepublic IBinder onBind(Intent intent) {    //mHandler = getApplication().getHandler();    return mBinder;}public void toast(String mess){    Toast.makeText(this,mess,Toast.LENGTH_SHORT).show();}private final IBinder mBinder = new LocalBinder();public class LocalBinder extends Binder {    BluetoothServices getService() {        // Return this instance of LocalService so clients can call public methods        return BluetoothServices.this;    }}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {    String deviceg = intent.getStringExtra("bluetooth_device");    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();            connectToDevice(deviceg);    return START_STICKY;}private synchronized void connectToDevice(String macAddress){    BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(macAddress);    if (mState == STATE_CONNECTING){        if (mConnectThread != null){            mConnectThread.cancel();            mConnectThread = null;        }    }    if (mConnectedThread != null){        mConnectedThread.cancel();        mConnectedThread = null;    }    mConnectThread = new ConnectBtThread(device);    toast("connecting");    mConnectThread.start();    setState(STATE_CONNECTING);}private void setState(int state){    mState = state;    if (mHandler != null){       // mHandler.obtainMessage();    }}public synchronized void stop(){    setState(STATE_NONE);    if (mConnectThread != null){        mConnectThread.cancel();        mConnectThread = null;    }    if (mConnectedThread != null){        mConnectedThread.cancel();        mConnectedThread = null;    }    if (mBluetoothAdapter != null){        mBluetoothAdapter.cancelDiscovery();    }    stopSelf();}public void sendData(String message){    if (mConnectedThread!= null){        mConnectedThread.write(message.getBytes());        toast("sent data");    }else {        Toast.makeText(BluetoothServices.this,"Failed to send data",Toast.LENGTH_SHORT).show();    }}@Overridepublic boolean stopService(Intent name) {    setState(STATE_NONE);    if (mConnectThread != null){        mConnectThread.cancel();        mConnectThread = null;    }    if (mConnectedThread != null){        mConnectedThread.cancel();        mConnectedThread = null;    }    mBluetoothAdapter.cancelDiscovery();    return super.stopService(name);}/*private synchronized void connected(BluetoothSocket mmSocket){    if (mConnectThread != null){        mConnectThread.cancel();        mConnectThread = null;    }    if (mConnectedThread != null){        mConnectedThread.cancel();        mConnectedThread = null;    }    mConnectedThread = new ConnectedBtThread(mmSocket);    mConnectedThread.start();    setState(STATE_CONNECTED);}*/private class ConnectBtThread extends Thread{    private final BluetoothSocket mSocket;    private final BluetoothDevice mDevice;    public ConnectBtThread(BluetoothDevice device){        mDevice = device;        BluetoothSocket socket = null;        try {            socket = device.createInsecureRfcommSocketToServiceRecord(UUID.fromString(B_UUID));        } catch (IOException e) {            e.printStackTrace();        }        mSocket = socket;    }    @Override    public void run() {        mBluetoothAdapter.cancelDiscovery();        try {            mSocket.connect();            Log.d("service","connect thread run method (connected)");            SharedPreferences pre = getSharedPreferences("BT_NAME",0);            pre.edit().putString("bluetooth_connected",mDevice.getName()).apply();        } catch (IOException e) {            try {                mSocket.close();                Log.d("service","connect thread run method ( close function)");            } catch (IOException e1) {                e1.printStackTrace();            }            e.printStackTrace();        }        //connected(mSocket);        mConnectedThread = new ConnectedBtThread(mSocket);        mConnectedThread.start();    }    public void cancel(){        try {            mSocket.close();            Log.d("service","connect thread cancel method");        } catch (IOException e) {            e.printStackTrace();        }    }}private class ConnectedBtThread extends Thread{    private final BluetoothSocket cSocket;    private final InputStream inS;    private final OutputStream outS;    private byte[] buffer;    public ConnectedBtThread(BluetoothSocket socket){        cSocket = socket;        InputStream tmpIn = null;        OutputStream tmpOut = null;        try {            tmpIn = socket.getInputStream();        } catch (IOException e) {            e.printStackTrace();        }        try {            tmpOut = socket.getOutputStream();        } catch (IOException e) {            e.printStackTrace();        }        inS = tmpIn;        outS = tmpOut;    }    @Override    public void run() {        buffer = new byte[1024];        int mByte;        try {            mByte= inS.read(buffer);        } catch (IOException e) {            e.printStackTrace();        }        Log.d("service","connected thread run method");    }    public void write(byte[] buff){        try {            outS.write(buff);        } catch (IOException e) {            e.printStackTrace();        }    }    private void cancel(){        try {            cSocket.close();            Log.d("service","connected thread cancel method");        } catch (IOException e) {            e.printStackTrace();        }    }}@Overridepublic void onDestroy() {    this.stop();    super.onDestroy();}

}