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// 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,
);
},
);
}
}