import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: const MyHomePage(),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  bool? _checkValue = false;
  int _selectedRadio = 1;
  bool _switchValue = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Checkbox(
                value: _checkValue,
                onChanged: (bool? value) =>
                    setState(() => _checkValue = value)),
            Radio<int>(
                value: 0,
                groupValue: _selectedRadio,
                onChanged: (int? value) => setState(() => _selectedRadio = 0)),
            Radio<int>(
                value: 1,
                groupValue: _selectedRadio,
                onChanged: (int? value) => setState(() => _selectedRadio = 1)),
            Radio<int>(
                value: 2,
                groupValue: _selectedRadio,
                onChanged: (int? value) => setState(() => _selectedRadio = 2)),
            Switch(
                value: _switchValue,
                onChanged: (bool value) =>
                    setState(() => _switchValue = value)),
          ],
        ),
      ),
    );
  }
}