// 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. import 'dart:math' as math; import 'package:flutter/material.dart'; /// Flutter code sample for [AnimatedBuilder]. void main() => runApp(const AnimatedBuilderExampleApp()); class AnimatedBuilderExampleApp extends StatelessWidget { const AnimatedBuilderExampleApp({super.key}); @override Widget build(BuildContext context) { return const MaterialApp( home: AnimatedBuilderExample(), ); } } class AnimatedBuilderExample extends StatefulWidget { const AnimatedBuilderExample({super.key}); @override State<AnimatedBuilderExample> createState() => _AnimatedBuilderExampleState(); } /// AnimationControllers can be created with `vsync: this` because of /// TickerProviderStateMixin. class _AnimatedBuilderExampleState extends State<AnimatedBuilderExample> 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 AnimatedBuilder( animation: _controller, child: Container( width: 200.0, height: 200.0, color: Colors.green, child: const Center( child: Text('Whee!'), ), ), builder: (BuildContext context, Widget? child) { return Transform.rotate( angle: _controller.value * 2.0 * math.pi, child: child, ); }, ); } }