Bluetooth connection

main.dart

class _BluetoothAppState extends State<BluetoothApp> {
  ...

  @override
  void initState() {
    super.initState();
    bluetoothConnectionState();
  }

  // We are using async callback for using await
  Future<void> bluetoothConnectionState() async {
    List<BluetoothDevice> devices = [];

    // To get the list of paired devices
    try {
      devices = await bluetooth.getBondedDevices();
    } on PlatformException {
      print("Error");
    }

    // For knowing when bluetooth is connected and when disconnected
    bluetooth.onStateChanged().listen((state) {
      switch (state) {
        case FlutterBluetoothSerial.CONNECTED:
          setState(() {
            _connected = true;
            _pressed = false;
          });

          break;

        case FlutterBluetoothSerial.DISCONNECTED:
          setState(() {
            _connected = false;
            _pressed = false;
          });
          break;

        default:
          print(state);
          break;
      }
    });

    // It is an error to call [setState] unless [mounted] is true.
    if (!mounted) {
      return;
    }

    // Store the [devices] list in the [_devicesList] for accessing
    // the list outside this class
    setState(() {
      _devicesList = devices;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      // We have to work on the UI in this part
    );
  }
}