Flutter Radio Widget Tutorial

main.dart

import 'package:flutter/material.dart';
 
void main() => runApp(const MyApp());
 
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
 
  static const String _title = 'Flutter Tutorial';
 
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatefulWidget(),
      ),
    );
  }
}
 
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);
 
  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}
 
enum OS { mac, windows, linux }
 
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  OS? _os = OS.mac;
 
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        children: <Widget>[
          const SizedBox(height: 30,),
          const Text('Which Operating System are your currently using?'),
          const SizedBox(height: 10,),
          ListTile(
            title: const Text('Mac'),
            leading: Radio<OS>(
              value: OS.mac,
              groupValue: _os,
              onChanged: (OS? value) {
                setState(() {
                  _os = value;
                });
              },
            )
          ),
          ListTile(
            title: const Text('Windows'),
            leading: Radio<OS>(
              value: OS.windows,
              groupValue: _os,
              onChanged: (OS? value) {
                setState(() {
                  _os = value;
                });
              },
            )
          ),
          ListTile(
              title: const Text('Linux'),
              leading: Radio<OS>(
                value: OS.linux,
                groupValue: _os,
                onChanged: (OS? value) {
                  setState(() {
                    _os = value;
                  });
                },
              )
          ),
        ],
      ),
    );
  }
}