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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 [ScrollMetricsNotification].
void main() => runApp(const ScrollMetricsDemo());
class ScrollMetricsDemo extends StatefulWidget {
const ScrollMetricsDemo({super.key});
@override
State<ScrollMetricsDemo> createState() => ScrollMetricsDemoState();
}
class ScrollMetricsDemoState extends State<ScrollMetricsDemo> {
double windowSize = 200.0;
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('ScrollMetrics Demo'),
),
floatingActionButton: FloatingActionButton(
child: const Icon(Icons.add),
onPressed: () => setState(() {
windowSize += 10.0;
}),
),
body: NotificationListener<ScrollMetricsNotification>(
onNotification: (ScrollMetricsNotification notification) {
ScaffoldMessenger.of(notification.context).showSnackBar(
const SnackBar(
content: Text('Scroll metrics changed!'),
),
);
return false;
},
child: Scrollbar(
thumbVisibility: true,
child: SizedBox(
height: windowSize,
width: double.infinity,
child: const SingleChildScrollView(
primary: true,
child: FlutterLogo(
size: 300.0,
),
),
),
),
),
),
);
}
}