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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 'dart:io' show Platform;
import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
class Leaf extends StatefulWidget {
const Leaf({
super.key,
required this.child,
});
final Widget child;
@override
State<Leaf> createState() => _LeafState();
}
class _LeafState extends State<Leaf> {
bool _keepAlive = false;
void setKeepAlive(bool value) {
setState(() { _keepAlive = value; });
}
@override
Widget build(BuildContext context) {
return KeepAlive(
keepAlive: _keepAlive,
child: widget.child,
);
}
}
List<Widget> generateList(Widget child) {
return List<Widget>.generate(
100,
(int index) => Leaf(
key: GlobalObjectKey<_LeafState>(index),
child: child,
),
growable: false,
);
}
void main() {
test('KeepAlive debugTypicalAncestorWidgetClass', () {
final KeepAlive keepAlive = KeepAlive(keepAlive: false, child: Container());
expect(
keepAlive.debugTypicalAncestorWidgetDescription,
'SliverWithKeepAliveWidget or TwoDimensionalViewport',
);
});
testWidgets('KeepAlive with ListView with itemExtent', (WidgetTester tester) async {
await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: ListView(
cacheExtent: 0.0,
addAutomaticKeepAlives: false,
addRepaintBoundaries: false,
addSemanticIndexes: false,
itemExtent: 12.3, // about 50 widgets visible
children: generateList(const Placeholder()),
),
),
);
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
await tester.drag(find.byType(ListView), const Offset(0.0, -300.0)); // about 25 widgets' worth
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(true);
await tester.drag(find.byType(ListView), const Offset(0.0, 300.0)); // back to top
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(false);
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
});
testWidgets('KeepAlive with ListView without itemExtent', (WidgetTester tester) async {
await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: ListView(
cacheExtent: 0.0,
addAutomaticKeepAlives: false,
addRepaintBoundaries: false,
addSemanticIndexes: false,
children: generateList(const SizedBox(height: 12.3, child: Placeholder())), // about 50 widgets visible
),
),
);
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
await tester.drag(find.byType(ListView), const Offset(0.0, -300.0)); // about 25 widgets' worth
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(true);
await tester.drag(find.byType(ListView), const Offset(0.0, 300.0)); // back to top
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(false);
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
});
testWidgets('KeepAlive with GridView', (WidgetTester tester) async {
await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: GridView.count(
cacheExtent: 0.0,
addAutomaticKeepAlives: false,
addRepaintBoundaries: false,
addSemanticIndexes: false,
crossAxisCount: 2,
childAspectRatio: 400.0 / 24.6, // about 50 widgets visible
children: generateList(const Placeholder()),
),
),
);
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
await tester.drag(find.byType(GridView), const Offset(0.0, -300.0)); // about 25 widgets' worth
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(true);
await tester.drag(find.byType(GridView), const Offset(0.0, 300.0)); // back to top
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60)), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
const GlobalObjectKey<_LeafState>(60).currentState!.setKeepAlive(false);
await tester.pump();
expect(find.byKey(const GlobalObjectKey<_LeafState>(3)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(30)), findsOneWidget);
expect(find.byKey(const GlobalObjectKey<_LeafState>(59), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(60), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(61), skipOffstage: false), findsNothing);
expect(find.byKey(const GlobalObjectKey<_LeafState>(90), skipOffstage: false), findsNothing);
});
testWidgets('KeepAlive render tree description', (WidgetTester tester) async {
await tester.pumpWidget(
Directionality(
textDirection: TextDirection.ltr,
child: ListView(
addAutomaticKeepAlives: false,
addRepaintBoundaries: false,
addSemanticIndexes: false,
itemExtent: 400.0, // 2 visible children
children: generateList(const Placeholder()),
),
),
);
// The important lines below are the ones marked with "<----"
expect(tester.binding.renderView.toStringDeep(minLevel: DiagnosticLevel.info), equalsIgnoringHashCodes(
'_ReusableRenderView#00000\n'
' │ debug mode enabled - ${Platform.operatingSystem}\n'
' │ view size: Size(2400.0, 1800.0) (in physical pixels)\n'
' │ device pixel ratio: 3.0 (physical pixels per logical pixel)\n'
' │ configuration: BoxConstraints(w=800.0, h=600.0) at 3.0x (in\n'
' │ logical pixels)\n'
' │\n'
' └─child: RenderRepaintBoundary#00000\n'
' │ needs compositing\n'
' │ parentData: <none>\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ metrics: 0.0% useful (1 bad vs 0 good)\n'
' │ diagnosis: insufficient data to draw conclusion (less than five\n'
' │ repaints)\n'
' │\n'
' └─child: RenderCustomPaint#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ painter: null\n'
' │ foregroundPainter:\n'
' │ _GlowingOverscrollIndicatorPainter(_GlowController(color:\n'
' │ Color(0xffffffff), axis: vertical), _GlowController(color:\n'
' │ Color(0xffffffff), axis: vertical))\n'
' │\n'
' └─child: RenderRepaintBoundary#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ metrics: 0.0% useful (1 bad vs 0 good)\n'
' │ diagnosis: insufficient data to draw conclusion (less than five\n'
' │ repaints)\n'
' │\n'
' └─child: _RenderScrollSemantics#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ semantics node: SemanticsNode#1\n'
' │ semantic boundary\n'
' │ size: Size(800.0, 600.0)\n'
' │\n'
' └─child: RenderPointerListener#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: deferToChild\n'
' │ listeners: signal\n'
' │\n'
' └─child: RenderSemanticsGestureHandler#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: opaque\n'
' │ gestures: vertical scroll\n'
' │\n'
' └─child: RenderPointerListener#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: opaque\n'
' │ listeners: down, panZoomStart\n'
' │\n'
' └─child: RenderSemanticsAnnotations#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │\n'
' └─child: RenderIgnorePointer#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ ignoring: false\n'
' │ ignoringSemantics: null\n'
' │\n'
' └─child: RenderViewport#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ axisDirection: down\n'
' │ crossAxisDirection: right\n'
' │ offset: ScrollPositionWithSingleContext#00000(offset: 0.0, range:\n'
' │ 0.0..39400.0, viewport: 600.0, ScrollableState,\n'
' │ AlwaysScrollableScrollPhysics -> ClampingScrollPhysics ->\n'
' │ RangeMaintainingScrollPhysics, IdleScrollActivity#00000,\n'
' │ ScrollDirection.idle)\n'
' │ anchor: 0.0\n'
' │\n'
' └─center child: RenderSliverPadding#00000 relayoutBoundary=up1\n'
' │ parentData: paintOffset=Offset(0.0, 0.0) (can use size)\n'
' │ constraints: SliverConstraints(AxisDirection.down,\n'
' │ GrowthDirection.forward, ScrollDirection.idle, scrollOffset:\n'
' │ 0.0, precedingScrollExtent: 0.0, remainingPaintExtent: 600.0,\n'
' │ crossAxisExtent: 800.0, crossAxisDirection:\n'
' │ AxisDirection.right, viewportMainAxisExtent: 600.0,\n'
' │ remainingCacheExtent: 850.0, cacheOrigin: 0.0)\n'
' │ geometry: SliverGeometry(scrollExtent: 40000.0, paintExtent:\n'
' │ 600.0, maxPaintExtent: 40000.0, hasVisualOverflow: true,\n'
' │ cacheExtent: 850.0)\n'
' │ padding: EdgeInsets.zero\n'
' │ textDirection: ltr\n'
' │\n'
' └─child: RenderSliverFixedExtentList#00000 relayoutBoundary=up2\n'
' │ parentData: paintOffset=Offset(0.0, 0.0) (can use size)\n'
' │ constraints: SliverConstraints(AxisDirection.down,\n'
' │ GrowthDirection.forward, ScrollDirection.idle, scrollOffset:\n'
' │ 0.0, precedingScrollExtent: 0.0, remainingPaintExtent: 600.0,\n'
' │ crossAxisExtent: 800.0, crossAxisDirection:\n'
' │ AxisDirection.right, viewportMainAxisExtent: 600.0,\n'
' │ remainingCacheExtent: 850.0, cacheOrigin: 0.0)\n'
' │ geometry: SliverGeometry(scrollExtent: 40000.0, paintExtent:\n'
' │ 600.0, maxPaintExtent: 40000.0, hasVisualOverflow: true,\n'
' │ cacheExtent: 850.0)\n'
' │ currently live children: 0 to 2\n'
' │\n'
' ├─child with index 0: RenderLimitedBox#00000\n'
' │ │ parentData: index=0; layoutOffset=0.0\n'
' │ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ │ size: Size(800.0, 400.0)\n'
' │ │ maxWidth: 400.0\n'
' │ │ maxHeight: 400.0\n'
' │ │\n'
' │ └─child: RenderCustomPaint#00000\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ painter: _PlaceholderPainter#00000()\n'
' │ preferredSize: Size(Infinity, Infinity)\n'
' │\n'
' ├─child with index 1: RenderLimitedBox#00000\n' // <----- no dashed line starts here
' │ │ parentData: index=1; layoutOffset=400.0\n'
' │ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ │ size: Size(800.0, 400.0)\n'
' │ │ maxWidth: 400.0\n'
' │ │ maxHeight: 400.0\n'
' │ │\n'
' │ └─child: RenderCustomPaint#00000\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ painter: _PlaceholderPainter#00000()\n'
' │ preferredSize: Size(Infinity, Infinity)\n'
' │\n'
' └─child with index 2: RenderLimitedBox#00000 NEEDS-PAINT\n'
' │ parentData: index=2; layoutOffset=800.0\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ maxWidth: 400.0\n'
' │ maxHeight: 400.0\n'
' │\n'
' └─child: RenderCustomPaint#00000 NEEDS-PAINT\n'
' parentData: <none> (can use size)\n'
' constraints: BoxConstraints(w=800.0, h=400.0)\n'
' size: Size(800.0, 400.0)\n'
' painter: _PlaceholderPainter#00000()\n'
' preferredSize: Size(Infinity, Infinity)\n',
));
const GlobalObjectKey<_LeafState>(0).currentState!.setKeepAlive(true);
await tester.drag(find.byType(ListView), const Offset(0.0, -1000.0));
await tester.pump();
const GlobalObjectKey<_LeafState>(3).currentState!.setKeepAlive(true);
await tester.drag(find.byType(ListView), const Offset(0.0, -1000.0));
await tester.pump();
expect(tester.binding.renderView.toStringDeep(minLevel: DiagnosticLevel.info), equalsIgnoringHashCodes(
'_ReusableRenderView#00000\n'
' │ debug mode enabled - ${Platform.operatingSystem}\n'
' │ view size: Size(2400.0, 1800.0) (in physical pixels)\n'
' │ device pixel ratio: 3.0 (physical pixels per logical pixel)\n'
' │ configuration: BoxConstraints(w=800.0, h=600.0) at 3.0x (in\n'
' │ logical pixels)\n'
' │\n'
' └─child: RenderRepaintBoundary#00000\n'
' │ needs compositing\n'
' │ parentData: <none>\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ metrics: 0.0% useful (1 bad vs 0 good)\n'
' │ diagnosis: insufficient data to draw conclusion (less than five\n'
' │ repaints)\n'
' │\n'
' └─child: RenderCustomPaint#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ painter: null\n'
' │ foregroundPainter:\n'
' │ _GlowingOverscrollIndicatorPainter(_GlowController(color:\n'
' │ Color(0xffffffff), axis: vertical), _GlowController(color:\n'
' │ Color(0xffffffff), axis: vertical))\n'
' │\n'
' └─child: RenderRepaintBoundary#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ metrics: 0.0% useful (1 bad vs 0 good)\n'
' │ diagnosis: insufficient data to draw conclusion (less than five\n'
' │ repaints)\n'
' │\n'
' └─child: _RenderScrollSemantics#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ semantics node: SemanticsNode#1\n'
' │ semantic boundary\n'
' │ size: Size(800.0, 600.0)\n'
' │\n'
' └─child: RenderPointerListener#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: deferToChild\n'
' │ listeners: signal\n'
' │\n'
' └─child: RenderSemanticsGestureHandler#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: opaque\n'
' │ gestures: vertical scroll\n'
' │\n'
' └─child: RenderPointerListener#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ behavior: opaque\n'
' │ listeners: down, panZoomStart\n'
' │\n'
' └─child: RenderSemanticsAnnotations#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │\n'
' └─child: RenderIgnorePointer#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ size: Size(800.0, 600.0)\n'
' │ ignoring: false\n'
' │ ignoringSemantics: null\n'
' │\n'
' └─child: RenderViewport#00000\n'
' │ needs compositing\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=600.0)\n'
' │ layer: OffsetLayer#00000\n'
' │ size: Size(800.0, 600.0)\n'
' │ axisDirection: down\n'
' │ crossAxisDirection: right\n'
' │ offset: ScrollPositionWithSingleContext#00000(offset: 2000.0,\n'
' │ range: 0.0..39400.0, viewport: 600.0, ScrollableState,\n'
' │ AlwaysScrollableScrollPhysics -> ClampingScrollPhysics ->\n'
' │ RangeMaintainingScrollPhysics, IdleScrollActivity#00000,\n'
' │ ScrollDirection.idle)\n'
' │ anchor: 0.0\n'
' │\n'
' └─center child: RenderSliverPadding#00000 relayoutBoundary=up1\n'
' │ parentData: paintOffset=Offset(0.0, 0.0) (can use size)\n'
' │ constraints: SliverConstraints(AxisDirection.down,\n'
' │ GrowthDirection.forward, ScrollDirection.idle, scrollOffset:\n'
' │ 2000.0, precedingScrollExtent: 0.0, remainingPaintExtent:\n'
' │ 600.0, crossAxisExtent: 800.0, crossAxisDirection:\n'
' │ AxisDirection.right, viewportMainAxisExtent: 600.0,\n'
' │ remainingCacheExtent: 1100.0, cacheOrigin: -250.0)\n'
' │ geometry: SliverGeometry(scrollExtent: 40000.0, paintExtent:\n'
' │ 600.0, maxPaintExtent: 40000.0, hasVisualOverflow: true,\n'
' │ cacheExtent: 1100.0)\n'
' │ padding: EdgeInsets.zero\n'
' │ textDirection: ltr\n'
' │\n'
' └─child: RenderSliverFixedExtentList#00000 relayoutBoundary=up2\n'
' │ parentData: paintOffset=Offset(0.0, 0.0) (can use size)\n'
' │ constraints: SliverConstraints(AxisDirection.down,\n'
' │ GrowthDirection.forward, ScrollDirection.idle, scrollOffset:\n'
' │ 2000.0, precedingScrollExtent: 0.0, remainingPaintExtent:\n'
' │ 600.0, crossAxisExtent: 800.0, crossAxisDirection:\n'
' │ AxisDirection.right, viewportMainAxisExtent: 600.0,\n'
' │ remainingCacheExtent: 1100.0, cacheOrigin: -250.0)\n'
' │ geometry: SliverGeometry(scrollExtent: 40000.0, paintExtent:\n'
' │ 600.0, maxPaintExtent: 40000.0, hasVisualOverflow: true,\n'
' │ cacheExtent: 1100.0)\n'
' │ currently live children: 4 to 7\n'
' │\n'
' ├─child with index 4: RenderLimitedBox#00000 NEEDS-PAINT\n'
' │ │ parentData: index=4; layoutOffset=1600.0\n'
' │ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ │ size: Size(800.0, 400.0)\n'
' │ │ maxWidth: 400.0\n'
' │ │ maxHeight: 400.0\n'
' │ │\n'
' │ └─child: RenderCustomPaint#00000 NEEDS-PAINT\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ painter: _PlaceholderPainter#00000()\n'
' │ preferredSize: Size(Infinity, Infinity)\n'
' │\n'
' ├─child with index 5: RenderLimitedBox#00000\n' // <----- this is index 5, not 0
' │ │ parentData: index=5; layoutOffset=2000.0\n'
' │ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ │ size: Size(800.0, 400.0)\n'
' │ │ maxWidth: 400.0\n'
' │ │ maxHeight: 400.0\n'
' │ │\n'
' │ └─child: RenderCustomPaint#00000\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ painter: _PlaceholderPainter#00000()\n'
' │ preferredSize: Size(Infinity, Infinity)\n'
' │\n'
' ├─child with index 6: RenderLimitedBox#00000\n'
' │ │ parentData: index=6; layoutOffset=2400.0\n'
' │ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ │ size: Size(800.0, 400.0)\n'
' │ │ maxWidth: 400.0\n'
' │ │ maxHeight: 400.0\n'
' │ │\n'
' │ └─child: RenderCustomPaint#00000\n'
' │ parentData: <none> (can use size)\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ painter: _PlaceholderPainter#00000()\n'
' │ preferredSize: Size(Infinity, Infinity)\n'
' │\n'
' ├─child with index 7: RenderLimitedBox#00000 NEEDS-PAINT\n'
' ╎ │ parentData: index=7; layoutOffset=2800.0\n'
' ╎ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' ╎ │ size: Size(800.0, 400.0)\n'
' ╎ │ maxWidth: 400.0\n'
' ╎ │ maxHeight: 400.0\n'
' ╎ │\n'
' ╎ └─child: RenderCustomPaint#00000 NEEDS-PAINT\n'
' ╎ parentData: <none> (can use size)\n'
' ╎ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' ╎ size: Size(800.0, 400.0)\n'
' ╎ painter: _PlaceholderPainter#00000()\n'
' ╎ preferredSize: Size(Infinity, Infinity)\n'
' ╎\n'
' ╎╌child with index 0 (kept alive but not laid out): RenderLimitedBox#00000\n' // <----- this one is index 0 and is marked as being kept alive but not laid out
' ╎ │ parentData: index=0; keepAlive; layoutOffset=0.0\n'
' ╎ │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' ╎ │ size: Size(800.0, 400.0)\n'
' ╎ │ maxWidth: 400.0\n'
' ╎ │ maxHeight: 400.0\n'
' ╎ │\n'
' ╎ └─child: RenderCustomPaint#00000\n'
' ╎ parentData: <none> (can use size)\n'
' ╎ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' ╎ size: Size(800.0, 400.0)\n'
' ╎ painter: _PlaceholderPainter#00000()\n'
' ╎ preferredSize: Size(Infinity, Infinity)\n'
' ╎\n'
' └╌child with index 3 (kept alive but not laid out): RenderLimitedBox#00000\n'
' │ parentData: index=3; keepAlive; layoutOffset=1200.0\n'
' │ constraints: BoxConstraints(w=800.0, h=400.0)\n'
' │ size: Size(800.0, 400.0)\n'
' │ maxWidth: 400.0\n'
' │ maxHeight: 400.0\n'
' │\n'
' └─child: RenderCustomPaint#00000\n'
' parentData: <none> (can use size)\n'
' constraints: BoxConstraints(w=800.0, h=400.0)\n'
' size: Size(800.0, 400.0)\n'
' painter: _PlaceholderPainter#00000()\n'
' preferredSize: Size(Infinity, Infinity)\n',
));
}, skip: kIsWeb); // https://github.com/flutter/flutter/issues/87876
}