Flutter Blue Setting Notifications

Question

I've been using flutter Blue for some now and I'm stuck on the following: I'm using the example App I downloaded on https://github.com/pauldemarco/flutter_blue, through here the basic idea is that as soon as I connect to my bluetooth device it starts checking if the service "FFE0" exists and then the characteristic "FFE1". This Characteristic spits out random strings I need for my project.

Image of screen with characteristic open

Through the screen I can see the above is true I just need to somehow automatically set notifications for the characteristic as soon as it connects to the bluetooth device.

This is some current code i'm testing out in the _Connect Function.

_connect(BluetoothDevice d) async {
    device = d;
    // Connect to device
    deviceConnection = _flutterBlue
        .connect(device, timeout: const Duration(seconds: 4))
        .listen(
      null,
      onDone: _disconnect,
    );

// Update the connection state immediately
    device.state.then((s) {
      setState(() {
        deviceState = s;
      });
    });

// Subscribe to connection changes
    deviceStateSubscription = device.onStateChanged().listen((s) {
      setState(() {
        deviceState = s;
      });
      if (s == BluetoothDeviceState.connected) {
        device.discoverServices().then((service) {
          service.forEach((_service){
            var characteristics = _service.characteristics;
            _service.characteristics.map((c) {
              print(c);
            });
            for(BluetoothCharacteristic _characteristic in characteristics) {
              device.readCharacteristic(_characteristic).then((_value){
                print(_value);
                if (_value.contains("FFE0")) {
                  print("Found!!");
              // do something 
                }
              });
            }
          });
          setState(() {
            services = service;
          });
          _getServices();
        });
      }
    });
  }

I maybe someone has a suggestion on how to approach my problem.

Robin

I solved it using github.com/Sensirion/smart-gadget-flutter/tree/master/lib — Robin
Robin, welcome to SO. Please could you write an answer to your own question and explain the "HOW". How did you solve it, which code did you change in your example etc? That will help the entire community. Thank you. — Sebastian Roth

Robin Robin · Accepted Answer · 2018-10-22T16:15:40

I found https://github.com/Sensirion/smart-gadget-flutter/tree/master/lib and I was able to fix my problem using the following code:

      for(BluetoothService service in services) {
        for(BluetoothCharacteristic c in service.characteristics) {
          if(c.uuid == new Guid("0000ffe1-0000-1000-8000-00805f9b34fb")) {
            _setNotification(c);
          } else {
            print("Nope");
          }
        }
      }

This was added in the _connect function.

_connect(BluetoothDevice d) async {
    device = d;
// Connect to device
    deviceConnection = _flutterBlue
        .connect(device, timeout: const Duration(seconds: 4))
        .listen(
      null,
      onDone: _disconnect,
    );

// Update the connection state immediately
    device.state.then((s) {
      setState(() {
        deviceState = s;
      });
    });

// Subscribe to connection changes
    deviceStateSubscription = device.onStateChanged().listen((s) {
      setState(() {
        deviceState = s;
      });
      if (s == BluetoothDeviceState.connected) {

        device.discoverServices().then((s) {

         services = s;

          for(BluetoothService service in services) {
            for(BluetoothCharacteristic c in service.characteristics) {
              if(c.uuid == new Guid("0000ffe1-0000-1000-8000-00805f9b34fb")) {
                _setNotification(c);
              } else {
                print("Nope");
              }
            }
          }
          setState(() {
            services = s;
          });
          _getServices();
        });
      }
    });
  }

Flutter Blue Setting Notifications

1 Answers