дал класс Bluetooth Activity в приложении для Android, который отлично работает для всех функций Bluetooth, таких как: сканирование, сопряжение, подключение, отправка и получение данных.

Настоящая проблема в том, когда Деятельность уничтожена. Bluetooth отключается.

Как я могу установить соединение Bluetooth во всем приложении. и я хочу отправить данные по Bluetooth из других действий.

Помогите мне реализовать это простым способом?

public class BTActivity extends AppCompatActivity {

ArrayList<BluetoothDevice> devices = new ArrayList<>();
BluetoothAdapter mBluetoothAdapter;
BluetoothDevice mBluetoothDevice;
ArrayAdapter<BluetoothDevice> arrayAdapter;

ConnectThread c;

private static final String TAG = "MY_BT";

ListView lvPaired;
Button BluetoothOnOff, ScanBt, pairedlist, sendButton, btDisconnect, incrementBtn, decrementBtn;
EditText input_text;
TextView ConnectedTo;

FragmentManager fm = getSupportFragmentManager();

UUID BHANU_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bt);

    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    lvPaired = findViewById(R.id.btPairedLV);
    pairedlist = findViewById(R.id.btPaired);
    input_text = findViewById(R.id.user_input);
    sendButton = findViewById(R.id.btnSend);
    BluetoothOnOff = findViewById(R.id.offOn_bt);
    ScanBt = findViewById(R.id.scan_bt);
    ConnectedTo = findViewById(R.id.current_connected_bluetooth);
    btDisconnect = findViewById(R.id.bt_disconnect);
    incrementBtn = findViewById(R.id.incrementBtn);
    decrementBtn = findViewById(R.id.decrementBtn);

    onClickListener();
    pairedList();

    IntentFilter filter = new IntentFilter();
    filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
    filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
    registerReceiver(mReceiver, filter);

}
public void onClickListener(){

    pairedlist.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (arrayAdapter != null){
                arrayAdapter.clear();
            }
            pairedList();
        }
    });

    lvPaired.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            BluetoothDevice device = (BluetoothDevice) parent.getItemAtPosition(position);
            c = new ConnectThread(device, true);
            c.start();
        }
    });
    sendButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String text = input_text.getText().toString();
            c.sendData(text);
            input_text.setText("");

        }
    });
    BluetoothOnOff.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (!mBluetoothAdapter.isEnabled()){
                mBluetoothAdapter.enable();
                BluetoothOnOff.setText("ON");
            }else {
                mBluetoothAdapter.disable();
                BluetoothOnOff.setText("OFF");
            }
        }
    });
    ScanBt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ScanFragment scanFragment = new ScanFragment();
            scanFragment.show(fm,"ScanBT");
            //ScanFragment scanFragment = new ScanFragment();
            //scanFragment.show(fm,"Scan Fragment");
        }
    });
    btDisconnect.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            c.cancel();
        }
    });

    incrementBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            c.sendData("a");
        }
    });
    decrementBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            c.sendData("b");
        }
    });

}


public void toast(String message) {
    Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}

@Override
protected void onDestroy() {
    unregisterReceiver(mReceiver);
    super.onDestroy();
}

public void pairedList() {
    //arrayAdapter.clear();
    devices.addAll(mBluetoothAdapter.getBondedDevices());
    arrayAdapter = new ArrayAdapter<BluetoothDevice>(this, android.R.layout.simple_list_item_1,android.R.id.text1, devices);
    lvPaired.setAdapter(arrayAdapter);
    arrayAdapter.notifyDataSetChanged();

}

BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
            toast("connected");
            BluetoothDevice device = intent
                    .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            ConnectedTo.setText(device.getName());
            btDisconnect.setVisibility(View.VISIBLE);
            //getActionBar().setSubtitle(device.getName());
            Log.d("BT", "connected to");
        } else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
            toast("disconnected");
            ConnectedTo.setText("None");
            btDisconnect.setVisibility(View.INVISIBLE);
           // getActionBar().setSubtitle("");
            Log.d("BT", "disconnected");
        }

    }
};


public class ConnectThread extends Thread {
    BluetoothDevice cDevice;
    BluetoothSocket socket;
    ConnectedThread ct;

    ConnectThread(BluetoothDevice device, boolean insecureConnection) {
        cDevice = device;
        try {
            if (insecureConnection) {
                socket = device.createInsecureRfcommSocketToServiceRecord(BHANU_UUID);
            } else {
                socket = device.createRfcommSocketToServiceRecord(BHANU_UUID);
            }
        } catch (IOException e) {
            e.getMessage();
        }
    }

    public void run() {
        mBluetoothAdapter.cancelDiscovery();

        try {
            Log.d("BT", "Socket ready to connect");
            socket.connect();
            Log.d("BT", "Socket connected");
            // out = socket.getOutputStream();
            // input = new BufferedReader(new InputStreamReader(socket.getInputStream()));


        } catch (final IOException e) {
            e.getMessage();
        }

        ct = new ConnectedThread(socket);

        //ct.write("Q-smart".getBytes());
            /*try {
                socket.close();
            } catch (final IOException closeException) {
                closeException.getMessage();
            }*/
    }
    private void sendData(String message){
        Log.d(TAG,message);
        if (socket != null){
            ct.write(message.getBytes());
        }else {
            toast("Please connect to bluetooth first");
        }
    }

    public void cancel() {
        try {
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

private class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final InputStream mmInStream;
    private final OutputStream mmOutStream;
    private byte[] mmBuffer; // mmBuffer store for the stream

    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();
        } catch (IOException e) {
            Log.e(TAG, "Error occurred when creating input stream", e);
        }
        try {
            tmpOut = socket.getOutputStream();
        } catch (IOException e) {
            Log.e(TAG, "Error occurred when creating output stream", e);
        }

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }

    public void run() {
        mmBuffer = new byte[1024];
        int numBytes; // bytes returned from read()

        // Keep listening to the InputStream until an exception occurs.
        while (true) {
            try {
                // Read from the InputStream.
                numBytes = mmInStream.read(mmBuffer);
                // Send the obtained bytes to the UI activity.
               /* Message readMsg = mHandler.obtainMessage(
                        MessageConstants.MESSAGE_READ, numBytes, -1,
                        mmBuffer);
                readMsg.sendToTarget();*/
            } catch (IOException e) {
                Log.d(TAG, "Input stream was disconnected", e);
                break;
            }
        }
    }

    // Call this from the main activity to send data to the remote device.
    public void write(byte[] bytes) {
        try {
            mmOutStream.write(bytes);

            // Share the sent message with the UI activity.
           /* Message writtenMsg = mHandler.obtainMessage(
                    MessageConstants.MESSAGE_WRITE, -1, -1, mmBuffer);
            writtenMsg.sendToTarget();*/
        } catch (IOException e) {
            Log.e(TAG, "Error occurred when sending data", e);

            // Send a failure message back to the activity.
           /* Message writeErrorMsg =
                    mHandler.obtainMessage(MessageConstants.MESSAGE_TOAST);
            Bundle bundle = new Bundle();
            bundle.putString("toast",
                    "Couldn't send data to the other device");
            writeErrorMsg.setData(bundle);
            mHandler.sendMessage(writeErrorMsg);*/
        }
    }


}
}