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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.
// Flutter code sample for AnimatedSwitcher
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 const MaterialApp(
title: _title,
home: MyStatefulWidget(),
);
}
}
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key? key}) : super(key: key);
@override
State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
int _count = 0;
@override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
AnimatedSwitcher(
duration: const Duration(milliseconds: 500),
transitionBuilder: (Widget child, Animation<double> animation) {
return ScaleTransition(scale: animation, child: child);
},
child: Text(
'$_count',
// This key causes the AnimatedSwitcher to interpret this as a "new"
// child each time the count changes, so that it will begin its animation
// when the count changes.
key: ValueKey<int>(_count),
style: Theme.of(context).textTheme.headline4,
),
),
ElevatedButton(
child: const Text('Increment'),
onPressed: () {
setState(() {
_count += 1;
});
},
),
],
),
);
}
}