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Fix the NestedScrollView exception when rebuilding during scheduleWarmUpFrame (#75308)

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xubaolin 2021-02-10 17:01:04 +08:00 committed by GitHub
parent 6ad9f784b3
commit 16af4aa7eb
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2 changed files with 50 additions and 2 deletions
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9
packages/flutter/lib/src/widgets/nested_scroll_view.dart
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@ -795,8 +795,13 @@ class _NestedScrollCoordinator implements ScrollActivityDelegate, ScrollHoldCont
bool get hasScrolledBody {
for (final _NestedScrollPosition position in _innerPositions) {
assert(position.hasContentDimensions && position.hasPixels);
if (position.pixels > position.minScrollExtent) {
if (!position.hasContentDimensions || !position.hasPixels) {
// It's possible that NestedScrollView built twice before layout phase
// in the same frame. This can happen when the FocusManager schedules a microTask
// that marks NestedScrollView dirty during the warm up frame.
// https://github.com/flutter/flutter/pull/75308
continue;
} else if (position.pixels > position.minScrollExtent) {
return true;
}
}

43
packages/flutter/test/widgets/nested_scroll_view_test.dart
View File

@ -2303,6 +2303,49 @@ void main() {
expect(lastUserScrollingDirection, ScrollDirection.forward);
});
// Regression test for https://github.com/flutter/flutter/issues/72257
testWidgets('NestedScrollView works well when rebuilding during scheduleWarmUpFrame', (WidgetTester tester) async {
bool? isScrolled;
final Widget myApp = MaterialApp(
home: Scaffold(
body: StatefulBuilder(
builder: (BuildContext context, StateSetter setState) {
return Focus(
onFocusChange: (_) => setState( (){} ),
child: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool boxIsScrolled) {
isScrolled = boxIsScrolled;
return <Widget>[
const SliverAppBar(
expandedHeight: 200,
title: Text('Test'),
)
];
},
body: CustomScrollView(
slivers: <Widget>[
SliverList(
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return const Text('');
},
childCount: 10,
),
)
],
),
),
);
},
),
),
);
await tester.pumpWidget(myApp, Duration.zero, EnginePhase.build);
expect(isScrolled, false);
expect(tester.takeException(), isNull);
});
}
class TestHeader extends SliverPersistentHeaderDelegate {