enum SingingCharacter { lafayette, jefferson }

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State {
  SingingCharacter? _character = SingingCharacter.lafayette;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        ListTile(
          title: const Text('Lafayette'),
          leading: Radio(
            value: SingingCharacter.lafayette,
            groupValue: _character,
            onChanged: (SingingCharacter? value) {
              setState(() {
                _character = value;
              });
            },
          ),
        ),
        ListTile(
          title: const Text('Thomas Jefferson'),
          leading: Radio(
            value: SingingCharacter.jefferson,
            groupValue: _character,
            onChanged: (SingingCharacter? value) {
              setState(() {
                _character = value;
              });
            },
          ),
        ),
      ],
    );
  }
}