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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_test/flutter_test.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter/material.dart';
void main() {
testWidgets('SliverList reverse children (with keys)', (WidgetTester tester) async {
final List<int> items = 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 = 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 = 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 = 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>((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 = 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 = 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);
});
testWidgets('SliverList should layout first child in case of child reordering', (WidgetTester tester) async {
// Regression test for https://github.com/flutter/flutter/issues/35904.
List<String> items = <String>['1', '2'];
await tester.pumpWidget(_buildSliverListRenderWidgetChild(items));
await tester.pumpAndSettle();
expect(find.text('Tile 1'), findsOneWidget);
expect(find.text('Tile 2'), findsOneWidget);
items = items.reversed.toList();
await tester.pumpWidget(_buildSliverListRenderWidgetChild(items));
await tester.pumpAndSettle();
expect(find.text('Tile 1'), findsOneWidget);
expect(find.text('Tile 2'), findsOneWidget);
});
}
Widget _buildSliverListRenderWidgetChild(List<String> items) {
return MaterialApp(
home: Directionality(
textDirection: TextDirection.ltr,
child: Material(
child: Container(
height: 500,
child: CustomScrollView(
controller: ScrollController(),
slivers: <Widget>[
SliverList(
delegate: SliverChildListDelegate(
items.map<Widget>((String item) {
return Chip(
key: Key(item),
label: Text('Tile $item'),
);
}).toList(),
),
),
],
),
),
),
),
);
}
Widget _buildSliverList({
List<int> items = const <int>[],
ScrollController controller,
double itemHeight = 500.0,
double viewportHeight = 300.0,
}) {
return Directionality(
textDirection: TextDirection.ltr,
child: Center(
child: Container(
height: viewportHeight,
child: CustomScrollView(
controller: controller,
slivers: <Widget>[
SliverList(
delegate: SliverChildBuilderDelegate(
(BuildContext context, int i) {
return Container(
key: ValueKey<int>(items[i]),
height: itemHeight,
child: Text('Tile ${items[i]}'),
);
},
childCount: items.length,
),
),
],
),
),
),
);
}