[CP] Revert "Remove hack from PageView." (#141977) (#141995)
Reverts flutter/flutter#141533
b/321743868
diff --git a/examples/api/test/widgets/page_view/page_view.0_test.dart b/examples/api/test/widgets/page_view/page_view.0_test.dart
index 86876c2..a994f22 100644
--- a/examples/api/test/widgets/page_view/page_view.0_test.dart
+++ b/examples/api/test/widgets/page_view/page_view.0_test.dart
@@ -49,7 +49,7 @@
// Verify that page view index is also updated with same index to page indicator.
final PageView pageView = tester.widget<PageView>(find.byType(PageView));
- expect(pageView.controller!.page, 1);
+ expect(pageView.controller.page, 1);
// Tap backward button on page indicator area.
await tester.tap(find.byIcon(Icons.arrow_left_rounded));
diff --git a/packages/flutter/lib/src/widgets/page_view.dart b/packages/flutter/lib/src/widgets/page_view.dart
index 5da1f1c..33a139e 100644
--- a/packages/flutter/lib/src/widgets/page_view.dart
+++ b/packages/flutter/lib/src/widgets/page_view.dart
@@ -576,6 +576,11 @@
bool get allowImplicitScrolling => false;
}
+// Having this global (mutable) page controller is a bit of a hack. We need it
+// to plumb in the factory for _PagePosition, but it will end up accumulating
+// a large list of scroll positions. As long as you don't try to actually
+// control the scroll positions, everything should be fine.
+final PageController _defaultPageController = PageController();
const PageScrollPhysics _kPagePhysics = PageScrollPhysics();
/// A scrollable list that works page by page.
@@ -640,7 +645,7 @@
super.key,
this.scrollDirection = Axis.horizontal,
this.reverse = false,
- this.controller,
+ PageController? controller,
this.physics,
this.pageSnapping = true,
this.onPageChanged,
@@ -651,7 +656,8 @@
this.clipBehavior = Clip.hardEdge,
this.scrollBehavior,
this.padEnds = true,
- }) : childrenDelegate = SliverChildListDelegate(children);
+ }) : controller = controller ?? _defaultPageController,
+ childrenDelegate = SliverChildListDelegate(children);
/// Creates a scrollable list that works page by page using widgets that are
/// created on demand.
@@ -682,7 +688,7 @@
super.key,
this.scrollDirection = Axis.horizontal,
this.reverse = false,
- this.controller,
+ PageController? controller,
this.physics,
this.pageSnapping = true,
this.onPageChanged,
@@ -695,7 +701,8 @@
this.clipBehavior = Clip.hardEdge,
this.scrollBehavior,
this.padEnds = true,
- }) : childrenDelegate = SliverChildBuilderDelegate(
+ }) : controller = controller ?? _defaultPageController,
+ childrenDelegate = SliverChildBuilderDelegate(
itemBuilder,
findChildIndexCallback: findChildIndexCallback,
childCount: itemCount,
@@ -712,11 +719,11 @@
/// {@end-tool}
///
/// {@macro flutter.widgets.PageView.allowImplicitScrolling}
- const PageView.custom({
+ PageView.custom({
super.key,
this.scrollDirection = Axis.horizontal,
this.reverse = false,
- this.controller,
+ PageController? controller,
this.physics,
this.pageSnapping = true,
this.onPageChanged,
@@ -727,7 +734,7 @@
this.clipBehavior = Clip.hardEdge,
this.scrollBehavior,
this.padEnds = true,
- });
+ }) : controller = controller ?? _defaultPageController;
/// Controls whether the widget's pages will respond to
/// [RenderObject.showOnScreen], which will allow for implicit accessibility
@@ -769,7 +776,7 @@
/// An object that can be used to control the position to which this page
/// view is scrolled.
- final PageController? controller;
+ final PageController controller;
/// How the page view should respond to user input.
///
@@ -841,37 +848,10 @@
class _PageViewState extends State<PageView> {
int _lastReportedPage = 0;
- late PageController _controller;
-
@override
void initState() {
super.initState();
- _initController();
- _lastReportedPage = _controller.initialPage;
- }
-
- @override
- void dispose() {
- if (widget.controller == null) {
- _controller.dispose();
- }
- super.dispose();
- }
-
-
- void _initController() {
- _controller = widget.controller ?? PageController();
- }
-
- @override
- void didUpdateWidget(PageView oldWidget) {
- if (oldWidget.controller != widget.controller) {
- if (oldWidget.controller == null) {
- _controller.dispose();
- }
- _initController();
- }
- super.didUpdateWidget(oldWidget);
+ _lastReportedPage = widget.controller.initialPage;
}
AxisDirection _getDirection(BuildContext context) {
@@ -912,7 +892,7 @@
child: Scrollable(
dragStartBehavior: widget.dragStartBehavior,
axisDirection: axisDirection,
- controller: _controller,
+ controller: widget.controller,
physics: physics,
restorationId: widget.restorationId,
scrollBehavior: widget.scrollBehavior ?? ScrollConfiguration.of(context).copyWith(scrollbars: false),
@@ -928,7 +908,7 @@
clipBehavior: widget.clipBehavior,
slivers: <Widget>[
SliverFillViewport(
- viewportFraction: _controller.viewportFraction,
+ viewportFraction: widget.controller.viewportFraction,
delegate: widget.childrenDelegate,
padEnds: widget.padEnds,
),
@@ -944,7 +924,7 @@
super.debugFillProperties(description);
description.add(EnumProperty<Axis>('scrollDirection', widget.scrollDirection));
description.add(FlagProperty('reverse', value: widget.reverse, ifTrue: 'reversed'));
- description.add(DiagnosticsProperty<PageController>('controller', _controller, showName: false));
+ description.add(DiagnosticsProperty<PageController>('controller', widget.controller, showName: false));
description.add(DiagnosticsProperty<ScrollPhysics>('physics', widget.physics, showName: false));
description.add(FlagProperty('pageSnapping', value: widget.pageSnapping, ifFalse: 'snapping disabled'));
description.add(FlagProperty('allowImplicitScrolling', value: widget.allowImplicitScrolling, ifTrue: 'allow implicit scrolling'));
diff --git a/packages/flutter/test/material/tabs_test.dart b/packages/flutter/test/material/tabs_test.dart
index 3cc05a4..f2c6cb9 100644
--- a/packages/flutter/test/material/tabs_test.dart
+++ b/packages/flutter/test/material/tabs_test.dart
@@ -1482,7 +1482,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -1531,7 +1531,7 @@
expect(tabController.index, 0);
final PageView pageView = tester.widget<PageView>(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
expect(position.pixels, 0.0);
@@ -1592,7 +1592,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
// The TabView was initialized with viewportFraction as 0.8
// So it's expected the PageView inside would obtain the same viewportFraction
@@ -1635,7 +1635,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
// The TabView was initialized with default viewportFraction
// So it's expected the PageView inside would obtain the value 1
@@ -1680,13 +1680,13 @@
await tester.pumpWidget(buildFrame(0.8));
PageView pageView = tester.widget(find.byType(PageView));
- PageController pageController = pageView.controller!;
+ PageController pageController = pageView.controller;
expect(pageController.viewportFraction, 0.8);
// Rebuild with a different viewport fraction.
await tester.pumpWidget(buildFrame(0.5));
pageView = tester.widget(find.byType(PageView));
- pageController = pageView.controller!;
+ pageController = pageView.controller;
expect(pageController.viewportFraction, 0.5);
});
@@ -1861,7 +1861,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -1905,7 +1905,7 @@
expect(tabController.index, 0);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -1950,7 +1950,7 @@
expect(tabController.index, 0);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -1999,7 +1999,7 @@
expect(tabController.index, 0);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -2050,7 +2050,7 @@
expect(tabController.index, 0);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -2246,7 +2246,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -2432,7 +2432,7 @@
expect(tabController.index, 1);
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
// The TabBarView's page width is 400, so page 0 is at scroll offset 0.0,
@@ -4208,7 +4208,7 @@
await tester.pumpWidget(buildFrame(15));
PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController1 = pageView.controller!;
+ final PageController pageController1 = pageView.controller;
TabController tabController = DefaultTabController.of(tester.element(find.text('Page 14')));
expect(tabController.index, 14);
expect(pageController1.page, 14);
@@ -4216,7 +4216,7 @@
// Rebuild with a new default tab controller with more tabs.
await tester.pumpWidget(buildFrame(10));
pageView = tester.widget(find.byType(PageView));
- final PageController pageController2 = pageView.controller!;
+ final PageController pageController2 = pageView.controller;
tabController = DefaultTabController.of(tester.element(find.text('Page 9')));
expect(tabController.index, 9);
expect(pageController2.page, 9);
@@ -5065,7 +5065,7 @@
double expectedIndicatorLeft = canvas.indicatorRect.left;
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
void pageControllerListener() {
// Whenever TabBarView scrolls due to changing TabController's index,
// check if indicator stays idle in its expectedIndicatorLeft
@@ -5225,7 +5225,7 @@
));
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
final ScrollPosition position = pageController.position;
expect(tabController.index, 0);
@@ -5715,7 +5715,7 @@
await tester.pumpWidget(buildFrame(controller1, showLast: true));
final PageView pageView = tester.widget(find.byType(PageView));
- final PageController pageController = pageView.controller!;
+ final PageController pageController = pageView.controller;
await tester.tap(find.text('three'));
await tester.pumpAndSettle();
expect(controller1.index, 2);
@@ -5782,7 +5782,7 @@
await tester.pumpWidget(buildFrame(controller1, showLast: true));
PageView pageView = tester.widget(find.byType(PageView));
- PageController pageController = pageView.controller!;
+ PageController pageController = pageView.controller;
await tester.tap(find.text('three'));
await tester.pumpAndSettle();
expect(controller1.index, 2);
@@ -5792,7 +5792,7 @@
await tester.pumpWidget(buildFrame(controller2, showLast: false));
await tester.pumpAndSettle();
pageView = tester.widget(find.byType(PageView));
- pageController = pageView.controller!;
+ pageController = pageView.controller;
expect(controller2.index, 0);
expect(pageController.page, 0);
@@ -5800,7 +5800,7 @@
await tester.pumpWidget(buildFrame(controller1, showLast: true));
await tester.pumpAndSettle();
pageView = tester.widget(find.byType(PageView));
- pageController = pageView.controller!;
+ pageController = pageView.controller;
expect(controller1.index, 2);
expect(pageController.page, 2);
});
diff --git a/packages/flutter/test/widgets/page_view_test.dart b/packages/flutter/test/widgets/page_view_test.dart
index aee04df..afebbba 100644
--- a/packages/flutter/test/widgets/page_view_test.dart
+++ b/packages/flutter/test/widgets/page_view_test.dart
@@ -1309,77 +1309,4 @@
expect(attach, 1);
expect(detach, 1);
});
-
- group('$PageView handles change of controller', () {
- final GlobalKey key = GlobalKey();
-
- Widget createPageView(PageController? controller) {
- return MaterialApp(
- home: Scaffold(
- body: PageView(
- key: key,
- controller: controller,
- children: const <Widget>[
- Center(child: Text('0')),
- Center(child: Text('1')),
- Center(child: Text('2')),
- ],
- ),
- ),
- );
- }
-
- Future<void> testPageViewWithController(PageController controller, WidgetTester tester, bool controls) async {
- int curentVisiblePage() {
- return int.parse(tester.widgetList(find.byType(Text)).whereType<Text>().first.data!);
- }
-
- final int initialPageInView = curentVisiblePage();
-
- for (int i = 0; i < 3; i++) {
- if (controls) {
- controller.jumpToPage(i);
- await tester.pumpAndSettle();
- expect(curentVisiblePage(), i);
- } else {
- expect(()=> controller.jumpToPage(i), throwsAssertionError);
- expect(curentVisiblePage(), initialPageInView);
- }
- }
- }
-
- testWidgets('null to value', (WidgetTester tester) async {
- final PageController controller = PageController();
- addTearDown(controller.dispose);
- await tester.pumpWidget(createPageView(null));
- await tester.pumpWidget(createPageView(controller));
- await testPageViewWithController(controller, tester, true);
- });
-
- testWidgets('value to value', (WidgetTester tester) async {
- final PageController controller1 = PageController();
- addTearDown(controller1.dispose);
- final PageController controller2 = PageController();
- addTearDown(controller2.dispose);
- await tester.pumpWidget(createPageView(controller1));
- await testPageViewWithController(controller1, tester, true);
- await tester.pumpWidget(createPageView(controller2));
- await testPageViewWithController(controller1, tester, false);
- await testPageViewWithController(controller2, tester, true);
- });
-
- testWidgets('value to null', (WidgetTester tester) async {
- final PageController controller = PageController();
- addTearDown(controller.dispose);
- await tester.pumpWidget(createPageView(controller));
- await testPageViewWithController(controller, tester, true);
- await tester.pumpWidget(createPageView(null));
- await testPageViewWithController(controller, tester, false);
- });
-
- testWidgets('null to null', (WidgetTester tester) async {
- await tester.pumpWidget(createPageView(null));
- await tester.pumpWidget(createPageView(null));
- });
- });
}
