如何在flutter中使用控制器获取单选按钮数据？

enum Gender { male, female }

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  Gender selectedGender;
  
  @override
  Widget build(BuildContext context) {
    // ...
  }
}

@override
Widget build(BuildContext context) {
  return Column(
    children: [
      RadioListTile<Gender>(
        title: const Text('Male'),
        value: Gender.male,
        groupValue: selectedGender,
        onChanged: (Gender value) {
          setState(() {
            selectedGender = value;
          });
        },
      ),
      RadioListTile<Gender>(
        title: const Text('Female'),
        value: Gender.female,
        groupValue: selectedGender,
        onChanged: (Gender value) {
          setState(() {
            selectedGender = value;
          });
        },
      ),
    ],
  );
}

void submit() {
  if (selectedGender == Gender.male) {
    // 处理男性选项被选中的情况
  } else if (selectedGender == Gender.female) {
    // 处理女性选项被选中的情况
  } else {
    // 处理未选择任何选项的情况
  }
}