// 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 TweenAnimationBuilder 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 MaterialApp( title: _title, home: Scaffold( appBar: AppBar(title: const Text(_title)), body: const Center( child: MyStatefulWidget(), ), ), ); } } class MyStatefulWidget extends StatefulWidget { const MyStatefulWidget({Key? key}) : super(key: key); @override State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); } class _MyStatefulWidgetState extends State<MyStatefulWidget> { double targetValue = 24.0; @override Widget build(BuildContext context) { return TweenAnimationBuilder<double>( tween: Tween<double>(begin: 0, end: targetValue), duration: const Duration(seconds: 1), builder: (BuildContext context, double size, Widget? child) { return IconButton( iconSize: size, color: Colors.blue, icon: child!, onPressed: () { setState(() { targetValue = targetValue == 24.0 ? 48.0 : 24.0; }); }, ); }, child: const Icon(Icons.aspect_ratio), ); } }