// 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 get _progress => listenable as Animation; @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 createState() => _MyStatefulWidgetState(); } /// [AnimationController]s can be created with `vsync: this` because of /// [TickerProviderStateMixin]. class _MyStatefulWidgetState extends State 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); } }