examples/api/lib/material/expansion_tile/expansion_tile.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.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 ExpansionTile
//
//***************************************************************************
//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)

// This example demonstrates different configurations of ExpansionTile.

//* ▲▲▲▲▲▲▲▲ 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 MyStatefulWidget(),
      ),
    );
  }
}

/// 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)

  bool _customTileExpanded = false;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        const ExpansionTile(
          title: Text('ExpansionTile 1'),
          subtitle: Text('Trailing expansion arrow icon'),
          children: <Widget>[
            ListTile(title: Text('This is tile number 1')),
          ],
        ),
        ExpansionTile(
          title: const Text('ExpansionTile 2'),
          subtitle: const Text('Custom expansion arrow icon'),
          trailing: Icon(
            _customTileExpanded
                ? Icons.arrow_drop_down_circle
                : Icons.arrow_drop_down,
          ),
          children: const <Widget>[
            ListTile(title: Text('This is tile number 2')),
          ],
          onExpansionChanged: (bool expanded) {
            setState(() => _customTileExpanded = expanded);
          },
        ),
        const ExpansionTile(
          title: Text('ExpansionTile 3'),
          subtitle: Text('Leading expansion arrow icon'),
          controlAffinity: ListTileControlAffinity.leading,
          children: <Widget>[
            ListTile(title: Text('This is tile number 3')),
          ],
        ),
      ],
    );
  }

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

}