sliver_fixed_extent_layout_test.dart 7.72 KB
Newer Older
Ian Hickson's avatar
Ian Hickson committed
1
// Copyright 2014 The Flutter Authors. All rights reserved.
2 3 4 5
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/rendering.dart';
6
import 'package:flutter_test/flutter_test.dart';
7 8 9 10

import 'rendering_tester.dart';

void main() {
11 12
  TestRenderingFlutterBinding.ensureInitialized();

13 14 15 16
  test('RenderSliverFixedExtentList layout test - rounding error', () {
    final List<RenderBox> children = <RenderBox>[
      RenderSizedBox(const Size(400.0, 100.0)),
      RenderSizedBox(const Size(400.0, 100.0)),
17
      RenderSizedBox(const Size(400.0, 100.0)),
18 19 20 21 22 23 24 25 26
    ];
    final TestRenderSliverBoxChildManager childManager = TestRenderSliverBoxChildManager(
      children: children,
    );
    final RenderViewport root = RenderViewport(
      crossAxisDirection: AxisDirection.right,
      offset: ViewportOffset.zero(),
      cacheExtent: 0,
      children: <RenderSliver>[
27
        childManager.createRenderSliverFillViewport(),
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
      ],
    );
    layout(root);
    expect(children[0].attached, true);
    expect(children[1].attached, false);

    root.offset = ViewportOffset.fixed(600);
    pumpFrame();
    expect(children[0].attached, false);
    expect(children[1].attached, true);

    // Simulate double precision error.
    root.offset = ViewportOffset.fixed(1199.999999999998);
    pumpFrame();
    expect(children[1].attached, false);
    expect(children[2].attached, true);
  });
45 46 47 48 49

  group('getMaxChildIndexForScrollOffset', () {
    // Regression test for https://github.com/flutter/flutter/issues/68182

    const double genericItemExtent = 600.0;
50 51
    const double extraValueToNotHaveRoundingIssues = 1e-10;
    const double extraValueToHaveRoundingIssues = 1e-11;
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

    test('should be 0 when item extent is 0', () {
      const double offsetValueWhichDoesntCare = 1234;
      final int actual = testGetMaxChildIndexForScrollOffset(offsetValueWhichDoesntCare, 0);
      expect(actual, 0);
    });

    test('should be 0 when offset is 0', () {
      final int actual = testGetMaxChildIndexForScrollOffset(0, genericItemExtent);
      expect(actual, 0);
    });

    test('should be 0 when offset is equal to item extent', () {
      final int actual = testGetMaxChildIndexForScrollOffset(genericItemExtent, genericItemExtent);
      expect(actual, 0);
    });

    test('should be 1 when offset is greater than item extent', () {
70
      final int actual = testGetMaxChildIndexForScrollOffset(genericItemExtent + 1, genericItemExtent);
71 72 73 74 75
      expect(actual, 1);
    });

    test('should be 1 when offset is slightly greater than item extent', () {
      final int actual = testGetMaxChildIndexForScrollOffset(
76 77 78
        genericItemExtent + extraValueToNotHaveRoundingIssues,
        genericItemExtent,
      );
79 80 81 82
      expect(actual, 1);
    });

    test('should be 4 when offset is four times and a half greater than item extent', () {
83
      final int actual = testGetMaxChildIndexForScrollOffset(genericItemExtent * 4.5, genericItemExtent);
84 85 86 87 88 89
      expect(actual, 4);
    });

    test('should be 5 when offset is 6 times greater than item extent', () {
      const double anotherGenericItemExtent = 414.0;
      final int actual = testGetMaxChildIndexForScrollOffset(
90 91 92
        anotherGenericItemExtent * 6,
        anotherGenericItemExtent,
      );
93 94 95
      expect(actual, 5);
    });

96
    test('should be 5 when offset is 6 times greater than a specific item extent where the division will return more than 13 zero decimals', () {
97
      const double itemExtentSpecificForAProblematicScreenSize = 411.42857142857144;
98
      final int actual = testGetMaxChildIndexForScrollOffset(
99 100
        itemExtentSpecificForAProblematicScreenSize * 6 + extraValueToHaveRoundingIssues,
        itemExtentSpecificForAProblematicScreenSize,
101
      );
102 103 104
      expect(actual, 5);
    });

105
    test('should be 0 when offset is a bit greater than item extent', () {
106
      final int actual = testGetMaxChildIndexForScrollOffset(
107 108 109
        genericItemExtent + extraValueToHaveRoundingIssues,
        genericItemExtent,
      );
110 111 112
      expect(actual, 0);
    });
  });
113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150

  test('Implements paintsChild correctly', () {
    final List<RenderBox> children = <RenderBox>[
      RenderSizedBox(const Size(400.0, 100.0)),
      RenderSizedBox(const Size(400.0, 100.0)),
      RenderSizedBox(const Size(400.0, 100.0)),
    ];
    final TestRenderSliverBoxChildManager childManager = TestRenderSliverBoxChildManager(
      children: children,
    );
    final RenderViewport root = RenderViewport(
      crossAxisDirection: AxisDirection.right,
      offset: ViewportOffset.zero(),
      cacheExtent: 0,
      children: <RenderSliver>[
        childManager.createRenderSliverFillViewport(),
      ],
    );
    layout(root);
    expect(children.first.parent, isA<RenderSliverMultiBoxAdaptor>());

    final RenderSliverMultiBoxAdaptor parent = children.first.parent! as RenderSliverMultiBoxAdaptor;
    expect(parent.paintsChild(children[0]), true);
    expect(parent.paintsChild(children[1]), false);
    expect(parent.paintsChild(children[2]), false);

    root.offset = ViewportOffset.fixed(600);
    pumpFrame();
    expect(parent.paintsChild(children[0]), false);
    expect(parent.paintsChild(children[1]), true);
    expect(parent.paintsChild(children[2]), false);

    root.offset = ViewportOffset.fixed(1200);
    pumpFrame();
    expect(parent.paintsChild(children[0]), false);
    expect(parent.paintsChild(children[1]), false);
    expect(parent.paintsChild(children[2]), true);
  });
151 152 153 154 155
}

int testGetMaxChildIndexForScrollOffset(double scrollOffset, double itemExtent) {
  final TestRenderSliverFixedExtentBoxAdaptor renderSliver = TestRenderSliverFixedExtentBoxAdaptor();
  return renderSliver.getMaxChildIndexForScrollOffset(scrollOffset, itemExtent);
156 157 158 159
}

class TestRenderSliverBoxChildManager extends RenderSliverBoxChildManager {
  TestRenderSliverBoxChildManager({
160
    required this.children,
161 162
  });

163
  RenderSliverMultiBoxAdaptor? _renderObject;
164 165
  List<RenderBox> children;

166
  RenderSliverFillViewport createRenderSliverFillViewport() {
167
    assert(_renderObject == null);
168
    _renderObject = RenderSliverFillViewport(
169 170
      childManager: this,
    );
171
    return _renderObject! as RenderSliverFillViewport;
172 173
  }

174
  int? _currentlyUpdatingChildIndex;
175 176

  @override
177
  void createChild(int index, { required RenderBox? after }) {
178
    if (index < 0 || index >= children.length) {
179
      return;
180
    }
181 182
    try {
      _currentlyUpdatingChildIndex = index;
183
      _renderObject!.insert(children[index], after: after);
184 185 186 187 188 189 190
    } finally {
      _currentlyUpdatingChildIndex = null;
    }
  }

  @override
  void removeChild(RenderBox child) {
191
    _renderObject!.remove(child);
192 193 194 195
  }

  @override
  double estimateMaxScrollOffset(
196
    SliverConstraints constraints, {
197 198 199 200
    int? firstIndex,
    int? lastIndex,
    double? leadingScrollOffset,
    double? trailingScrollOffset,
201
  }) {
202 203
    assert(lastIndex! >= firstIndex!);
    return children.length * (trailingScrollOffset! - leadingScrollOffset!) / (lastIndex! - firstIndex! + 1);
204 205 206 207 208 209 210 211
  }

  @override
  int get childCount => children.length;

  @override
  void didAdoptChild(RenderBox child) {
    assert(_currentlyUpdatingChildIndex != null);
212
    final SliverMultiBoxAdaptorParentData childParentData = child.parentData! as SliverMultiBoxAdaptorParentData;
213 214 215 216 217 218
    childParentData.index = _currentlyUpdatingChildIndex;
  }

  @override
  void setDidUnderflow(bool value) { }
}
219 220 221 222 223 224 225 226 227 228 229 230 231

class TestRenderSliverFixedExtentBoxAdaptor extends RenderSliverFixedExtentBoxAdaptor {
  TestRenderSliverFixedExtentBoxAdaptor()
    :super(childManager: TestRenderSliverBoxChildManager(children: <RenderBox>[]));

  @override
  int getMaxChildIndexForScrollOffset(double scrollOffset, double itemExtent) {
    return super.getMaxChildIndexForScrollOffset(scrollOffset, itemExtent);
  }

  @override
  double get itemExtent => throw UnimplementedError();
}