readCharacteristic method

@override Future<Uint8List?> readCharacteristic({ required String serviceUuid, required String characteristicUuid, Duration timeout = const Duration(seconds: 30), })

readCharacteristic reads the value of a BLE characteristic. The return value is the raw bytes of the characteristic.

If the characteristic is not readable, this method will return null.

Implementation

@override
Future<Uint8List?> readCharacteristic({
  required String serviceUuid,
  required String characteristicUuid,
  Duration timeout = const Duration(seconds: 30),
}) async {
  if (_currentConnected == null) {
    log("No device connected");
    return null;
  }

  final services = await _currentConnected!.discoverServices();
  final service = services.firstWhereOrNull((s) => s.uuid.toLowerCase() == serviceUuid.toLowerCase());
  if (service == null) {
    log("Service not found: $serviceUuid");
    return null;
  }

  if (_notifications.containsKey(characteristicUuid)) {
    log("Stop notify before reading");
    return null;
  }

  try {
    final characteristic = await service.getCharacteristic(characteristicUuid);
    final value = await characteristic.readValue(timeout: timeout);
    return value.buffer.asUint8List();
  } catch (e) {
    log("Error getting characteristic: $e");
    return null;
  }
}