1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
// 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:async';
import 'package:flutter/material.dart';
import 'recorder.dart';
import 'test_data.dart';
/// Creates an infinite list of Material cards and scrolls it.
class BenchCardInfiniteScroll extends WidgetRecorder {
BenchCardInfiniteScroll.forward()
: initialOffset = 0.0,
finalOffset = 30000.0,
super(name: benchmarkName);
BenchCardInfiniteScroll.backward()
: initialOffset = 30000.0,
finalOffset = 0.0,
super(name: benchmarkNameBackward);
static const String benchmarkName = 'bench_card_infinite_scroll';
static const String benchmarkNameBackward = 'bench_card_infinite_scroll_backward';
final double initialOffset;
final double finalOffset;
@override
Widget createWidget() => MaterialApp(
title: 'Infinite Card Scroll Benchmark',
home: _InfiniteScrollCards(initialOffset, finalOffset),
);
}
class _InfiniteScrollCards extends StatefulWidget {
const _InfiniteScrollCards(this.initialOffset, this.finalOffset);
final double initialOffset;
final double finalOffset;
@override
State<_InfiniteScrollCards> createState() => _InfiniteScrollCardsState();
}
class _InfiniteScrollCardsState extends State<_InfiniteScrollCards> {
static const Duration stepDuration = Duration(seconds: 20);
late ScrollController scrollController;
late double offset;
@override
void initState() {
super.initState();
offset = widget.initialOffset;
scrollController = ScrollController(
initialScrollOffset: offset,
);
// Without the timer the animation doesn't begin.
Timer.run(() async {
await scrollController.animateTo(
widget.finalOffset,
curve: Curves.linear,
duration: stepDuration,
);
});
}
@override
void dispose() {
scrollController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return ListView.builder(
controller: scrollController,
itemExtent: 100.0,
itemBuilder: (BuildContext context, int index) {
return SizedBox(
height: 100.0,
child: Card(
elevation: 16.0,
child: Text(
'${lipsum[index % lipsum.length]} $index',
textAlign: TextAlign.center,
),
),
);
},
);
}
}