| // 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 AnimatedWidget |
| |
| import 'dart:math' as math; |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| class MyApp extends StatelessWidget { |
| const MyApp({super.key}); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return const MaterialApp( |
| title: _title, |
| home: MyStatefulWidget(), |
| ); |
| } |
| } |
| |
| class SpinningContainer extends AnimatedWidget { |
| const SpinningContainer({ |
| super.key, |
| required AnimationController controller, |
| }) : super(listenable: controller); |
| |
| Animation<double> get _progress => listenable as Animation<double>; |
| |
| @override |
| Widget build(BuildContext context) { |
| return Transform.rotate( |
| angle: _progress.value * 2.0 * math.pi, |
| child: Container(width: 200.0, height: 200.0, color: Colors.green), |
| ); |
| } |
| } |
| |
| class MyStatefulWidget extends StatefulWidget { |
| const MyStatefulWidget({super.key}); |
| |
| @override |
| State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); |
| } |
| |
| /// AnimationControllers can be created with `vsync: this` because of TickerProviderStateMixin. |
| class _MyStatefulWidgetState extends State<MyStatefulWidget> |
| with TickerProviderStateMixin { |
| late final AnimationController _controller = AnimationController( |
| duration: const Duration(seconds: 10), |
| vsync: this, |
| )..repeat(); |
| |
| @override |
| void dispose() { |
| _controller.dispose(); |
| super.dispose(); |
| } |
| |
| @override |
| Widget build(BuildContext context) { |
| return SpinningContainer(controller: _controller); |
| } |
| } |