flutter/examples/api/lib/material/radio/radio.0.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
//
// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
// of samples, and may be ignored if you are just exploring the sample.

// Flutter code sample for Radio
//
//***************************************************************************
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// Here is an example of Radio widgets wrapped in ListTiles, which is similar
// to what you could get with the RadioListTile widget.
//
// The currently selected character is passed into `groupValue`, which is
// maintained by the example's `State`. In this case, the first `Radio`
// will start off selected because `_character` is initialized to
// `SingingCharacter.lafayette`.
//
// If the second radio button is pressed, the example's state is updated
// with `setState`, updating `_character` to `SingingCharacter.jefferson`.
// This causes the buttons to rebuild with the updated `groupValue`, and
// therefore the selection of the second button.
//
// Requires one of its ancestors to be a [Material] widget.

//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
//***************************************************************************

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const Center(
          child: MyStatefulWidget(),
        ),
      ),
    );
  }
}

//*****************************************************************************
//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)

enum SingingCharacter { lafayette, jefferson }

//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
//*****************************************************************************

/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

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

/// This is the private State class that goes with MyStatefulWidget.
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
//********************************************************************
//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)

  SingingCharacter? _character = SingingCharacter.lafayette;

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

//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
//********************************************************************

}