| // 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. |
| |
| // Flutter code sample for CircularProgressIndicator |
| |
| 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 Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return const MaterialApp( |
| title: _title, |
| home: MyStatefulWidget(), |
| ); |
| } |
| } |
| |
| class MyStatefulWidget extends StatefulWidget { |
| const MyStatefulWidget({Key? key}) : super(key: key); |
| |
| @override |
| State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); |
| } |
| |
| /// AnimationControllers can be created with `vsync: this` because of TickerProviderStateMixin. |
| class _MyStatefulWidgetState extends State<MyStatefulWidget> |
| with TickerProviderStateMixin { |
| late AnimationController controller; |
| |
| @override |
| void initState() { |
| controller = AnimationController( |
| vsync: this, |
| duration: const Duration(seconds: 5), |
| )..addListener(() { |
| setState(() {}); |
| }); |
| controller.repeat(reverse: true); |
| super.initState(); |
| } |
| |
| @override |
| void dispose() { |
| controller.dispose(); |
| super.dispose(); |
| } |
| |
| @override |
| Widget build(BuildContext context) { |
| return Scaffold( |
| body: Padding( |
| padding: const EdgeInsets.all(20.0), |
| child: Column( |
| mainAxisAlignment: MainAxisAlignment.spaceEvenly, |
| children: <Widget>[ |
| Text( |
| 'Linear progress indicator with a fixed color', |
| style: Theme.of(context).textTheme.headline6, |
| ), |
| CircularProgressIndicator( |
| value: controller.value, |
| semanticsLabel: 'Linear progress indicator', |
| ), |
| ], |
| ), |
| ), |
| ); |
| } |
| } |