Problems with bluetooth android studio connection

I'm trying to make an application that connects to a Bluetooth module and then be able to navigate between different activities connected to the module.

The problem is that the connection in the main activity is fine but when I launch another activity the connection is lost.

Any ideas on how to keep the connection active or how to reconnect in the new activity ?

This is my code:

public class Pantalla_Principal extends AppCompatActivity {


    Handler bluetoothIn;
    final int handlerState = 0;
    TextView CajaDeInformacion = null;

    Button BotonPruebaDeConexion, BotonConfigurar, BotonSeleccionar, BotonEliminar, BotonSalir;


    public StringBuilder recDataString = new StringBuilder();
    public Pantalla_Principal.ConnectedThread mConnectedThread;
    public static final UUID BTMODULEUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
    public static String address;
    public static String Dispositivo;
    BluetoothDevice device;
    BluetoothAdapter myBluetooth = null;
    BluetoothSocket btSocket = null;

    public static String EXTRA_ADDRESS = "device_address";

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pantalla__principal);


        final Intent intent = this.getIntent();
        address = intent.getStringExtra(Pantalla_Conexion.EXTRA_ADDRESS);



        CajaDeInformacion = (TextView) findViewById(R.id.CajaDePruebas);
        BotonConfigurar = (Button) findViewById(R.id.BotonConfigurar);
        BotonSeleccionar = (Button) findViewById(R.id.BotonSeleccionar);
        BotonEliminar = (Button) findViewById(R.id.BotonEliminar);
        BotonPruebaDeConexion = (Button) findViewById(R.id.BotonPruebaDeConexion);
        BotonSalir = (Button) findViewById(R.id.BotonSalir);

        BotonPruebaDeConexion.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (btSocket != null) {
                    try {
                        btSocket.getOutputStream().write("Hola".toString().getBytes());
                    } catch (IOException e) {
                        Mensaje("Error");
                    }
                }

            }
        });


        BotonConfigurar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                Intent PantallaConfigurar = new Intent(Pantalla_Principal.this, Pantalla_Configuracion.class);


                startActivity(PantallaConfigurar);
                finish();


            }
        });

        BotonSeleccionar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                Intent PantallaTelevisores = new Intent(Pantalla_Principal.this, Plantilla_Televisores.class);
                PantallaTelevisores.putExtra(EXTRA_ADDRESS, address);
                PantallaTelevisores.putExtra(Dispositivo,device);
                //PantallaTelevisores.putExtra("Dispositivo",device)
                startActivity(PantallaTelevisores);



            }
        });


        BotonSalir.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (btSocket != null) {
                    try {
                        Mensaje("Conexion Finalizada");
                        btSocket.close();
                        finish();
                    } catch (IOException e) {
                        Mensaje("Error");
                    }
                }

            }
        });


        this.bluetoothIn = new Handler() {
            public void handleMessage(Message msg) {
                if (msg.what == 0) {

                    String readMessage = (String) msg.obj;
                    Pantalla_Principal.this.recDataString.append(readMessage);
                    Pantalla_Principal.this.CajaDeInformacion.setText("   ");
                    Pantalla_Principal.this.CajaDeInformacion.setText(recDataString);


                }
            }
        };


        this.myBluetooth = BluetoothAdapter.getDefaultAdapter();
        this.checkBTState();

    }

    public BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
        return device.createRfcommSocketToServiceRecord(BTMODULEUUID);
    }

    private void Mensaje(String s) {
        Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show();
    }


    public void onResume() {
        super.onResume();

        BluetoothDevice device = myBluetooth.getRemoteDevice(address);
        try {
            this.btSocket = this.createBluetoothSocket(device);
        } catch (IOException var7) {
            Toast.makeText(this.getBaseContext(), "Socket creation failed", 1).show();
        }

        try {
            this.btSocket.connect();
        } catch (IOException var6) {
            try {

                this.btSocket.close();
            } catch (IOException var5) {
                ;
            }
        }

        this.mConnectedThread = new Pantalla_Principal.ConnectedThread(this.btSocket);
        this.mConnectedThread.start();

    }

    public void onPause() {
        super.onPause();

        try {
            this.btSocket.close();
        } catch (IOException var2) {
            ;
        }

    }

    public void onStop() {
        super.onStop();
        try {
            this.btSocket.close();
        } catch (IOException var2) {
            ;
        }
    }

    public void checkBTState() {
        if (this.myBluetooth == null) {
            Toast.makeText(this.getBaseContext(), "Device does not support bluetooth", 1).show();
        } else if (!this.myBluetooth.isEnabled()) {
            Intent enableBtIntent = new Intent("android.bluetooth.adapter.action.REQUEST_ENABLE");
            this.startActivityForResult(enableBtIntent, 1);
        }

    }

    public class ConnectedThread extends Thread {
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException var6) {
                ;
            }

            this.mmInStream = tmpIn;
            this.mmOutStream = tmpOut;
        }

        public void run() {
            byte[] buffer = new byte[256];

            while (true) {
                try {
                    int bytes = this.mmInStream.read(buffer);
                    String readMessage = new String(buffer, 0, bytes);
                    Pantalla_Principal.this.bluetoothIn.obtainMessage(0, bytes, -1, readMessage).sendToTarget();

                } catch (IOException var4) {
                    return;
                }
            }
        }

    }


}