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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 'package:flutter/material.dart';
/// Flutter code sample for [SliverAnimatedOpacity].
void main() => runApp(const SliverAnimatedOpacityExampleApp());
class SliverAnimatedOpacityExampleApp extends StatelessWidget {
const SliverAnimatedOpacityExampleApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: const Text('SliverAnimatedOpacity Sample')),
body: const Center(
child: SliverAnimatedOpacityExample(),
),
),
);
}
}
class SliverAnimatedOpacityExample extends StatefulWidget {
const SliverAnimatedOpacityExample({super.key});
@override
State<SliverAnimatedOpacityExample> createState() => _SliverAnimatedOpacityExampleState();
}
class _SliverAnimatedOpacityExampleState extends State<SliverAnimatedOpacityExample>
with SingleTickerProviderStateMixin {
bool _visible = true;
@override
Widget build(BuildContext context) {
return CustomScrollView(slivers: <Widget>[
SliverAnimatedOpacity(
opacity: _visible ? 1.0 : 0.0,
duration: const Duration(milliseconds: 500),
sliver: SliverFixedExtentList(
itemExtent: 100.0,
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return Container(
color: index.isEven ? Colors.indigo[200] : Colors.orange[200],
);
},
childCount: 5,
),
),
),
SliverToBoxAdapter(
child: FloatingActionButton(
onPressed: () {
setState(() {
_visible = !_visible;
});
},
tooltip: 'Toggle opacity',
child: const Icon(Icons.flip),
)),
]);
}
}