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fixed item tracking on orientation change in some cases

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This commit is contained in:
Thibault Deckers 2021-06-10 13:34:22 +09:00
parent f1b1688108
commit 7ac6617154
2 changed files with 30 additions and 13 deletions
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40
lib/widgets/common/grid/item_tracker.dart
View file

@ -42,12 +42,15 @@ mixin GridItemTrackerMixin<T, U extends StatefulWidget> on State<U>, WidgetsBind
animate: e.animate, animate: e.animate,
highlightItem: e.highlightItem, highlightItem: e.highlightItem,
))); )));
_lastOrientation = _windowOrientation;
WidgetsBinding.instance!.addObserver(this); WidgetsBinding.instance!.addObserver(this);
WidgetsBinding.instance!.addPostFrameCallback((_) { _saveLayoutMetrics();
_lastSectionedListLayout = context.read<SectionedListLayout<T>>(); }
_lastScrollableSize = scrollableSize;
_lastOrientation = _windowOrientation; @override
}); void didUpdateWidget(covariant oldWidget) {
super.didUpdateWidget(oldWidget);
_saveLayoutMetrics();
} }
@override @override
@ -99,8 +102,6 @@ mixin GridItemTrackerMixin<T, U extends StatefulWidget> on State<U>, WidgetsBind
@override @override
void didChangeMetrics() { void didChangeMetrics() {
// the timing of `didChangeMetrics` is unreliable w.r.t. `MediaQuery` update (and following app layout)
// most of the time, this is called before `MediaQuery` is updated, but not all the time
final orientation = _windowOrientation; final orientation = _windowOrientation;
if (_lastOrientation != orientation) { if (_lastOrientation != orientation) {
_lastOrientation = orientation; _lastOrientation = orientation;
@ -108,6 +109,21 @@ mixin GridItemTrackerMixin<T, U extends StatefulWidget> on State<U>, WidgetsBind
} }
} }
Future<void> _saveLayoutMetrics() async {
// use a delay to obtain current layout metrics
// so that we can handle window orientation change beforehand with the previous metrics,
// regardless of the `MediaQuery`/`WidgetsBindingObserver` order uncertainty
await Future.delayed(const Duration(milliseconds: 500));
if (mounted) {
_lastSectionedListLayout = context.read<SectionedListLayout<T>>();
_lastScrollableSize = scrollableSize;
}
}
// the order of `WidgetsBindingObserver` metrics change notification is unreliable
// w.r.t. the `MediaQuery` update, and consequentially to this widget update
// `WidgetsBindingObserver` is notified mostly before, sometimes after, the widget update
void _onWindowOrientationChange() { void _onWindowOrientationChange() {
final layout = _lastSectionedListLayout; final layout = _lastSectionedListLayout;
final halfSize = _lastScrollableSize / 2; final halfSize = _lastScrollableSize / 2;
@ -123,12 +139,10 @@ mixin GridItemTrackerMixin<T, U extends StatefulWidget> on State<U>, WidgetsBind
} }
} }
WidgetsBinding.instance!.addPostFrameCallback((_) { if (pivotItem != null) {
if (pivotItem != null) { WidgetsBinding.instance!.addPostFrameCallback((_) {
context.read<HighlightInfo>().trackItem(pivotItem, animate: false); context.read<HighlightInfo>().trackItem(pivotItem, animate: false);
} });
_lastSectionedListLayout = context.read<SectionedListLayout<T>>(); }
_lastScrollableSize = scrollableSize;
});
} }
} }

3
lib/widgets/common/grid/section_layout.dart
View file

@ -217,6 +217,9 @@ class SectionedListLayout<T> {
return section[index]; return section[index];
} }
@override
String toString() => '$runtimeType#${shortHash(this)}{sectionCount=${sections.length} columnCount=$columnCount, tileExtent=$tileExtent}';
} }
class SectionLayout { class SectionLayout {