Radio 单选按钮

当groupValue与value值一致，认为被选中。

void main() {
  runApp(MyPage());
}

class MyPage extends StatelessWidget {
  const MyPage({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(theme: ThemeData(), home: RadioFul());
  }
}

class MyState extends State {
  var sex = "男";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("性格"), centerTitle: true),
      body: Row(
        children: [
          Text("请选择性别："),
          Radio(
            value: "男",
            groupValue: sex,
            onChanged: (value) {
              setState(() {
                sex = "男";
              });
            },
          ),
          Text("男"),
          Radio(
            value: "女",
            groupValue: sex,
            onChanged: (value) {
              setState(() {
                sex = "女";
              });
            },
          ),
          Text("女"),
          Text("  选择的性别：$sex")
        ],
      ),
    );
  }
}

class RadioFul extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return MyState();
  }
}

RadioListTile

void main() {
  runApp(MyPage());
}

class MyPage extends StatelessWidget {
  const MyPage({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(theme: ThemeData(), home: RadioFul());
  }
}

class MyState extends State {
  int selected = -1;

  List<String> list = ["Java", "Swift", "Dart", "Kotlin"];

  //A. Java B. Swift C. Dart D. Kotlin

  @override
  Widget build(BuildContext context) {
    Column column = Column(
      children: [
        Text("Flutter使用的编程语言是()"),
        RadioListTile(
          title: Text("A."),
          subtitle: Text(list[0]),
          value: 0,
          groupValue: selected,
          onChanged: (value) {
            setState(() {
              selected = value!;
            });
          },
        ),
        RadioListTile(
          title: Text("B."),
          subtitle: Text(list[1]),
          value: 1,
          groupValue: selected,
          onChanged: (value) {
            setState(() {
              selected = value!;
            });
          },
        ),RadioListTile(
          title: Text("C."),
          subtitle: Text(list[2]),
          value: 2,
          groupValue: selected,
          onChanged: (value) {
            setState(() {
              selected = value!;
            });
          },
        ),
        RadioListTile(
          title: Text("D."),
          subtitle: Text(list[3]),
          value: 3,
          groupValue: selected,
          onChanged: (value) {
            setState(() {
              selected = value!;
            });
          },
        ),
        Text("你的选择：$selected")
      ],
    );

    return Scaffold(
      appBar: AppBar(title: Text("单选题"), centerTitle: true),
      body: column,
    );
  }
}

class RadioFul extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return MyState();
  }
}