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Fix SliverPadding dropping the chain on scrollOffsetCorrection propagation (#14789)

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* Fix SliverPadding dropping the chain on scrollOffsetCorrection propagation

* review doc
This commit is contained in:
xster 2018-02-21 14:51:14 -08:00 committed by GitHub
parent 62addedc11
commit 1bdbfe7b52
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4
packages/flutter/lib/src/rendering/sliver.dart
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@ -520,6 +520,10 @@ class SliverGeometry extends Diagnosticable {
/// If this is non-zero after [RenderSliver.performLayout] returns, the scroll
/// offset will be adjusted by the parent and then the entire layout of the
/// parent will be rerun.
///
/// If the parent is also a [RenderSliver], it must propagate this value
/// in its own [RenderSliver.geometry] property until a viewport which adjusts
/// its offset based on this value.
final double scrollOffsetCorrection;
/// Asserts that this geometry is internally consistent.

6
packages/flutter/lib/src/rendering/sliver_padding.dart
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@ -189,6 +189,12 @@ class RenderSliverPadding extends RenderSliver with RenderObjectWithChildMixin<R
parentUsesSize: true,
);
final SliverGeometry childLayoutGeometry = child.geometry;
if (childLayoutGeometry.scrollOffsetCorrection != null) {
geometry = new SliverGeometry(
scrollOffsetCorrection: childLayoutGeometry.scrollOffsetCorrection,
);
return;
}
final double beforePaddingPaintExtent = calculatePaintOffset(
constraints,
from: 0.0,

65
packages/flutter/test/widgets/slivers_padding_test.dart
View File

@ -357,4 +357,69 @@ void main() {
);
expect(tester.renderObject<RenderSliverPadding>(find.byType(SliverPadding)).afterPadding, 1.0);
});
testWidgets('SliverPadding propagates geometry offset corrections', (WidgetTester tester) async {
Widget listBuilder(IndexedWidgetBuilder sliverChildBuilder) {
return new Directionality(
textDirection: TextDirection.ltr,
child: new CustomScrollView(
slivers: <Widget>[
new SliverPadding(
padding: EdgeInsets.zero,
sliver: new SliverList(
delegate: new SliverChildBuilderDelegate(
sliverChildBuilder,
childCount: 10,
),
),
),
],
),
);
}
await tester.pumpWidget(
listBuilder(
(BuildContext context, int index) {
return new Container(
height: 200.0,
child: new Center(
child: new Text(index.toString()),
),
);
},
),
);
await tester.drag(find.text('2'), const Offset(0.0, -300.0));
await tester.pump();
expect(
tester.getRect(find.widgetWithText(Container, '2')),
new Rect.fromLTRB(0.0, 100.0, 800.0, 300.0),
);
// Now item 0 is 400.0px and going back will underflow.
await tester.pumpWidget(
listBuilder(
(BuildContext context, int index) {
return new Container(
height: index == 0 ? 400.0 : 200.0,
child: new Center(
child: new Text(index.toString()),
),
);
},
),
);
await tester.drag(find.text('2'), const Offset(0.0, 300.0));
// On this one frame, the scroll correction must properly propagate.
await tester.pump();
expect(
tester.getRect(find.widgetWithText(Container, '0')),
new Rect.fromLTRB(0.0, -200.0, 800.0, 200.0),
);
});
}