device_data.dart

Future<void> _getDeviceModel() async {
  String _model;
  try {

    // 1
    final String result = await platformChannel.invokeMethod('getDeviceModel');

    // 2
    _model = result;
    
  } catch (e) {

    // 3
    _model = "Can't fetch the method: '$e'.";
  }

  // 4
  setState(() {
    _deviceModel = _model;
  });
}