Let’s walk through a simple example of implementing radio buttons in a Flutter application. Assume we have a list of colors, and we want the user to select their favorite one using radio buttons.

import 'package:flutter/material.dart';

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

class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
String _selectedColor;

@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Flutter Radio Buttons'),
),
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
RadioListTile<String>(
title: Text('Red'),
value: 'Red',
groupValue: _selectedColor,
onChanged: (value) {
setState(() {
_selectedColor = value;
});
},
),
RadioListTile<String>(
title: Text('Green'),
value: 'Green',
groupValue: _selectedColor,
onChanged: (value) {
setState(() {
_selectedColor = value;
});
},
),
RadioListTile<String>(
title: Text('Blue'),
value: 'Blue',
groupValue: _selectedColor,
onChanged: (value) {
setState(() {
_selectedColor = value;
});
},
),
],
),
),
);
}
}

In this example, we define a MyApp widget as a StatefulWidget since the selected color will change over time. The _selectedColor variable holds the currently selected color. We use RadioListTile for each color option, providing a label, value, current group value, and an onChanged callback to handle selection changes.