sliver_list_test.dart 6.23 KB
Newer Older
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180
// Copyright 2018 The Chromium 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_test/flutter_test.dart';
import 'package:flutter/widgets.dart';

void main() {
  testWidgets('SliverList reverse children (with keys)', (WidgetTester tester) async {
    final List<int> items = new List<int>.generate(20, (int i) => i);
    const double itemHeight = 300.0;
    const double viewportHeight = 500.0;

    const double scrollPosition = 18 * itemHeight;
    final ScrollController controller = new ScrollController(initialScrollOffset: scrollPosition);

    await tester.pumpWidget(_buildSliverList(
      items: items,
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    await tester.pumpAndSettle();

    expect(controller.offset, scrollPosition);
    expect(find.text('Tile 0'), findsNothing);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 18'), findsOneWidget);
    expect(find.text('Tile 19'), findsOneWidget);

    await tester.pumpWidget(_buildSliverList(
      items: items.reversed.toList(),
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    final int frames = await tester.pumpAndSettle();
    expect(frames, 1); // ensures that there is no (animated) bouncing of the scrollable

    expect(controller.offset, scrollPosition);
    expect(find.text('Tile 19'), findsNothing);
    expect(find.text('Tile 18'), findsNothing);
    expect(find.text('Tile 1'), findsOneWidget);
    expect(find.text('Tile 0'), findsOneWidget);

    controller.jumpTo(0.0);
    await tester.pumpAndSettle();

    expect(controller.offset, 0.0);
    expect(find.text('Tile 19'), findsOneWidget);
    expect(find.text('Tile 18'), findsOneWidget);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 0'), findsNothing);
  });

  testWidgets('SliverList replace children (with keys)', (WidgetTester tester) async {
    final List<int> items = new List<int>.generate(20, (int i) => i);
    const double itemHeight = 300.0;
    const double viewportHeight = 500.0;

    const double scrollPosition = 18 * itemHeight;
    final ScrollController controller = new ScrollController(initialScrollOffset: scrollPosition);

    await tester.pumpWidget(_buildSliverList(
      items: items,
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    await tester.pumpAndSettle();

    expect(controller.offset, scrollPosition);
    expect(find.text('Tile 0'), findsNothing);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 18'), findsOneWidget);
    expect(find.text('Tile 19'), findsOneWidget);

    await tester.pumpWidget(_buildSliverList(
      items: items.map((int i) => i + 100).toList(),
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    final int frames = await tester.pumpAndSettle();
    expect(frames, 1); // ensures that there is no (animated) bouncing of the scrollable

    expect(controller.offset, scrollPosition);
    expect(find.text('Tile 0'), findsNothing);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 18'), findsNothing);
    expect(find.text('Tile 19'), findsNothing);

    expect(find.text('Tile 100'), findsNothing);
    expect(find.text('Tile 101'), findsNothing);
    expect(find.text('Tile 118'), findsOneWidget);
    expect(find.text('Tile 119'), findsOneWidget);

    controller.jumpTo(0.0);
    await tester.pumpAndSettle();

    expect(controller.offset, 0.0);
    expect(find.text('Tile 100'), findsOneWidget);
    expect(find.text('Tile 101'), findsOneWidget);
    expect(find.text('Tile 118'), findsNothing);
    expect(find.text('Tile 119'), findsNothing);
  });

  testWidgets('SliverList replace with shorter children list (with keys)', (WidgetTester tester) async {
    final List<int> items = new List<int>.generate(20, (int i) => i);
    const double itemHeight = 300.0;
    const double viewportHeight = 500.0;

    final double scrollPosition = items.length * itemHeight - viewportHeight;
    final ScrollController controller = new ScrollController(initialScrollOffset: scrollPosition);

    await tester.pumpWidget(_buildSliverList(
      items: items,
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    await tester.pumpAndSettle();

    expect(controller.offset, scrollPosition);
    expect(find.text('Tile 0'), findsNothing);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 17'), findsNothing);
    expect(find.text('Tile 18'), findsOneWidget);
    expect(find.text('Tile 19'), findsOneWidget);

    await tester.pumpWidget(_buildSliverList(
      items: items.sublist(0, items.length - 1),
      controller: controller,
      itemHeight: itemHeight,
      viewportHeight: viewportHeight,
    ));
    final int frames = await tester.pumpAndSettle();
    expect(frames, greaterThan(1)); // ensure animation to bring tile17 into view

    expect(controller.offset, scrollPosition - itemHeight);
    expect(find.text('Tile 0'), findsNothing);
    expect(find.text('Tile 1'), findsNothing);
    expect(find.text('Tile 17'), findsOneWidget);
    expect(find.text('Tile 18'), findsOneWidget);
    expect(find.text('Tile 19'), findsNothing);
  });
}

Widget _buildSliverList({
  List<int> items: const <int>[],
  ScrollController controller,
  double itemHeight: 500.0,
  double viewportHeight: 300.0,
}) {
  return new Directionality(
    textDirection: TextDirection.ltr,
    child: new Center(
      child: new Container(
        height: viewportHeight,
        child: new CustomScrollView(
          controller: controller,
          slivers: <Widget>[
            new SliverList(
              delegate: new SliverChildBuilderDelegate(
                    (BuildContext context, int i) {
                  return new Container(
                    key: new ValueKey<int>(items[i]),
                    height: itemHeight,
                    child: new Text('Tile ${items[i]}'),
                  );
                },
                childCount: items.length,
              ),
            ),
          ],
        ),
      ),
    ),
  );
}