startNotify method

@override Future<bool?> startNotify({ required String serviceUuid, required String characteristicUuid, })

startNotify starts listening to notifications from a BLE characteristic. To stop listening, use stopNotify method and to get the notifications, use onNotify stream.

Implementation

@override
Future<bool?> startNotify({
  required String serviceUuid,
  required String characteristicUuid,
}) async {
  if (_connectedDevice == null) {
    log("Not connected to any device");
    return false;
  }

  final service = _connectedDevice!.gattServices.firstWhereOrNull((element) {
    return element.uuid.toString().toLowerCase() == serviceUuid.toLowerCase();
  });
  if (service == null) {
    log("Service not found: $serviceUuid");
    return false;
  }

  final characteristic = service.characteristics.firstWhereOrNull((element) {
    return element.uuid.toString().toLowerCase() == characteristicUuid.toLowerCase();
  });

  if (characteristic == null) {
    log("Characteristic not found: $characteristicUuid");
    return false;
  }

  if (characteristic.notifying) {
    log("Characteristic already notifying: $characteristicUuid");
    return false;
  }

  _notifications[characteristic.uuid] = characteristic.propertiesChanged.listen((events) {
    for (final event in events) {
      if (event == 'Value') {
        final receivedValue = characteristic.value;
        _notifyController.add(BleCharacteristicNotification(
          serviceUuid: serviceUuid,
          characteristicUuid: characteristicUuid,
          value: Uint8List.fromList(receivedValue),
        ));
      }
    }
  });
  await characteristic.startNotify();
  return true;
}