// 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/rendering.dart'; import 'package:flutter/widgets.dart'; import 'package:flutter_test/flutter_test.dart'; void verifyPaintPosition(GlobalKey key, Offset ideal) { final RenderObject target = key.currentContext!.findRenderObject()!; expect(target.parent, isA<RenderViewport>()); final SliverPhysicalParentData parentData = target.parentData! as SliverPhysicalParentData; final Offset actual = parentData.paintOffset; expect(actual, ideal); } void main() { testWidgets('Sliver appbars - scrolling', (WidgetTester tester) async { GlobalKey key1, key2, key3, key4, key5; await tester.pumpWidget( Directionality( textDirection: TextDirection.ltr, child: CustomScrollView( slivers: <Widget>[ BigSliver(key: key1 = GlobalKey()), SliverPersistentHeader(key: key2 = GlobalKey(), delegate: TestDelegate()), SliverPersistentHeader(key: key3 = GlobalKey(), delegate: TestDelegate()), BigSliver(key: key4 = GlobalKey()), BigSliver(key: key5 = GlobalKey()), ], ), ), ); final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position; final double max = RenderBigSliver.height * 3.0 + TestDelegate().maxExtent * 2.0 - 600.0; // 600 is the height of the test viewport assert(max < 10000.0); expect(max, 1450.0); expect(position.pixels, 0.0); expect(position.minScrollExtent, 0.0); expect(position.maxScrollExtent, max); position.animateTo(10000.0, curve: Curves.linear, duration: const Duration(minutes: 1)); await tester.pumpAndSettle(const Duration(milliseconds: 10)); expect(position.pixels, max); expect(position.minScrollExtent, 0.0); expect(position.maxScrollExtent, max); verifyPaintPosition(key1, Offset.zero); verifyPaintPosition(key2, Offset.zero); verifyPaintPosition(key3, Offset.zero); verifyPaintPosition(key4, Offset.zero); verifyPaintPosition(key5, const Offset(0.0, 50.0)); }); testWidgets('Sliver appbars - scrolling off screen', (WidgetTester tester) async { final GlobalKey key = GlobalKey(); final TestDelegate delegate = TestDelegate(); await tester.pumpWidget( Directionality( textDirection: TextDirection.ltr, child: CustomScrollView( slivers: <Widget>[ const BigSliver(), SliverPersistentHeader(key: key, delegate: delegate), const BigSliver(), const BigSliver(), ], ), ), ); final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position; position.animateTo(RenderBigSliver.height + delegate.maxExtent - 5.0, curve: Curves.linear, duration: const Duration(minutes: 1)); await tester.pumpAndSettle(const Duration(milliseconds: 1000)); final RenderBox box = tester.renderObject<RenderBox>(find.byType(Container)); final Rect rect = Rect.fromPoints(box.localToGlobal(Offset.zero), box.localToGlobal(box.size.bottomRight(Offset.zero))); expect(rect, equals(const Rect.fromLTWH(0.0, -195.0, 800.0, 200.0))); }); testWidgets('Sliver appbars - scrolling - overscroll gap is below header', (WidgetTester tester) async { await tester.pumpWidget( Directionality( textDirection: TextDirection.ltr, child: CustomScrollView( physics: const BouncingScrollPhysics(), slivers: <Widget>[ SliverPersistentHeader(delegate: TestDelegate()), SliverList( delegate: SliverChildListDelegate(<Widget>[ const SizedBox( height: 300.0, child: Text('X'), ), ]), ), ], ), ), ); expect(tester.getTopLeft(find.byType(Container)), Offset.zero); expect(tester.getTopLeft(find.text('X')), const Offset(0.0, 200.0)); final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position; position.jumpTo(-50.0); await tester.pump(); expect(tester.getTopLeft(find.byType(Container)), Offset.zero); expect(tester.getTopLeft(find.text('X')), const Offset(0.0, 250.0)); }); testWidgets('Sliver appbars const child delegate - scrolling - overscroll gap is below header', (WidgetTester tester) async { await tester.pumpWidget( Directionality( textDirection: TextDirection.ltr, child: CustomScrollView( physics: const BouncingScrollPhysics(), slivers: <Widget>[ SliverPersistentHeader(delegate: TestDelegate()), const SliverList( delegate: SliverChildListDelegate.fixed(<Widget>[ SizedBox( height: 300.0, child: Text('X'), ), ]), ), ], ), ), ); expect(tester.getTopLeft(find.byType(Container)), Offset.zero); expect(tester.getTopLeft(find.text('X')), const Offset(0.0, 200.0)); final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position; position.jumpTo(-50.0); await tester.pump(); expect(tester.getTopLeft(find.byType(Container)), Offset.zero); expect(tester.getTopLeft(find.text('X')), const Offset(0.0, 250.0)); }); } class TestDelegate extends SliverPersistentHeaderDelegate { @override double get maxExtent => 200.0; @override double get minExtent => 200.0; @override Widget build(BuildContext context, double shrinkOffset, bool overlapsContent) { return Container(height: maxExtent); } @override bool shouldRebuild(TestDelegate oldDelegate) => false; } class RenderBigSliver extends RenderSliver { static const double height = 550.0; double get paintExtent => (height - constraints.scrollOffset).clamp(0.0, constraints.remainingPaintExtent); @override void performLayout() { geometry = SliverGeometry( scrollExtent: height, paintExtent: paintExtent, maxPaintExtent: height, ); } } class BigSliver extends LeafRenderObjectWidget { const BigSliver({ super.key }); @override RenderBigSliver createRenderObject(BuildContext context) { return RenderBigSliver(); } }