flutter 3.44 pre

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/flutter/page/page_view.dart

@@ -99,13 +99,24 @@ class PageView<T extends HorizontalDragGestureRecognizer>
     List<Widget> children = const <Widget>[],
     this.dragStartBehavior = DragStartBehavior.start,
     this.allowImplicitScrolling = false,
+    ScrollCacheExtent? scrollCacheExtent,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
     this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
     required this.horizontalDragGestureRecognizer,
-  }) : childrenDelegate = SliverChildListDelegate(children);
+  }) : assert(
+         scrollCacheExtent == null ||
+             (scrollCacheExtent.value > 0.0) == allowImplicitScrolling,
+         'scrollCacheExtent and allowImplicitScrolling must be consistent: '
+         'scrollCacheExtent must be greater than 0.0 when allowImplicitScrolling is true, '
+         'and must be 0.0 when allowImplicitScrolling is false.',
+       ),
+       scrollCacheExtent =
+           scrollCacheExtent ??
+           ScrollCacheExtent.viewport(allowImplicitScrolling ? 1.0 : 0.0),
+       childrenDelegate = SliverChildListDelegate(children);
 
   final GestureRecognizerFactoryConstructor<T> horizontalDragGestureRecognizer;
 
@@ -147,13 +158,24 @@ class PageView<T extends HorizontalDragGestureRecognizer>
     int? itemCount,
     this.dragStartBehavior = DragStartBehavior.start,
     this.allowImplicitScrolling = false,
+    ScrollCacheExtent? scrollCacheExtent,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
     this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
     required this.horizontalDragGestureRecognizer,
-  }) : childrenDelegate = SliverChildBuilderDelegate(
+  }) : assert(
+         scrollCacheExtent == null ||
+             (scrollCacheExtent.value > 0.0) == allowImplicitScrolling,
+         'scrollCacheExtent and allowImplicitScrolling must be consistent: '
+         'scrollCacheExtent must be greater than 0.0 when allowImplicitScrolling is true, '
+         'and must be 0.0 when allowImplicitScrolling is false.',
+       ),
+       scrollCacheExtent =
+           scrollCacheExtent ??
+           ScrollCacheExtent.viewport(allowImplicitScrolling ? 1.0 : 0.0),
+       childrenDelegate = SliverChildBuilderDelegate(
          itemBuilder,
          findChildIndexCallback: findChildIndexCallback,
          childCount: itemCount,
@@ -170,7 +192,7 @@ class PageView<T extends HorizontalDragGestureRecognizer>
   /// {@end-tool}
   ///
   /// {@macro flutter.widgets.PageView.allowImplicitScrolling}
-  const PageView.custom({
+  PageView.custom({
     super.key,
     this.scrollDirection = Axis.horizontal,
     this.reverse = false,
@@ -181,14 +203,25 @@ class PageView<T extends HorizontalDragGestureRecognizer>
     required this.childrenDelegate,
     this.dragStartBehavior = DragStartBehavior.start,
     this.allowImplicitScrolling = false,
+    ScrollCacheExtent? scrollCacheExtent,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
     this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
     required this.horizontalDragGestureRecognizer,
-  });
+  }) : assert(
+         scrollCacheExtent == null ||
+             (scrollCacheExtent.value > 0.0) == allowImplicitScrolling,
+         'scrollCacheExtent and allowImplicitScrolling must be consistent: '
+         'scrollCacheExtent must be greater than 0.0 when allowImplicitScrolling is true, '
+         'and must be 0.0 when allowImplicitScrolling is false.',
+       ),
+       scrollCacheExtent =
+           scrollCacheExtent ??
+           ScrollCacheExtent.viewport(allowImplicitScrolling ? 1.0 : 0.0);
 
+  /// {@template flutter.widgets.PageView.allowImplicitScrolling}
   /// Controls whether the widget's pages will respond to
   /// [RenderObject.showOnScreen], which will allow for implicit accessibility
   /// scrolling.
@@ -200,8 +233,37 @@ class PageView<T extends HorizontalDragGestureRecognizer>
   /// With this flag set to true, when accessibility focus reaches the end of
   /// the current page and user attempts to move it to the next element, focus
   /// will traverse to the next page in the page view.
+  /// {@endtemplate}
   final bool allowImplicitScrolling;
 
+  /// {@macro flutter.rendering.RenderViewportBase.scrollCacheExtent}
+  ///
+  /// In [PageView], the default [scrollCacheExtent] uses
+  /// [ScrollCacheExtent.viewport], where the value represents the number of
+  /// viewport lengths to cache beyond the visible area.
+  ///
+  /// When [PageController.viewportFraction] is 1.0 (the default), this is
+  /// equivalent to the number of pages. For example,
+  /// `ScrollCacheExtent.viewport(2.0)` caches 2 pages before and after the
+  /// visible page.
+  ///
+  /// When [PageController.viewportFraction] is less than 1.0, multiple pages
+  /// may be visible in a single viewport, so `ScrollCacheExtent.viewport(1.0)`
+  /// may cache more than one additional page in each direction.
+  ///
+  /// [ScrollCacheExtent.pixels] can also be used to specify the cache extent
+  /// in logical pixels instead of viewport sizes.
+  ///
+  /// If [scrollCacheExtent] is specified, its value must be consistent with
+  /// [allowImplicitScrolling]: the value must be greater than 0.0 when
+  /// [allowImplicitScrolling] is true, and must be 0.0 when
+  /// [allowImplicitScrolling] is false.
+  ///
+  /// Defaults to `ScrollCacheExtent.viewport(1.0)` if
+  /// [allowImplicitScrolling] is true, and `ScrollCacheExtent.viewport(0.0)` if
+  /// [allowImplicitScrolling] is false.
+  final ScrollCacheExtent scrollCacheExtent;
+
   /// {@macro flutter.widgets.scrollable.restorationId}
   final String? restorationId;
 
@@ -392,11 +454,7 @@ class _PageViewState<T extends HorizontalDragGestureRecognizer>
             ScrollConfiguration.of(context).copyWith(scrollbars: false),
         viewportBuilder: (BuildContext context, ViewportOffset position) {
           return Viewport(
-            // TODO(dnfield): we should provide a way to set cacheExtent
-            // independent of implicit scrolling:
-            // https://github.com/flutter/flutter/issues/45632
-            cacheExtent: widget.allowImplicitScrolling ? 1.0 : 0.0,
-            cacheExtentStyle: CacheExtentStyle.viewport,
+            scrollCacheExtent: widget.scrollCacheExtent,
             axisDirection: axisDirection,
             offset: position,
             clipBehavior: widget.clipBehavior,
@@ -405,6 +463,7 @@ class _PageViewState<T extends HorizontalDragGestureRecognizer>
                 viewportFraction: _controller.viewportFraction,
                 delegate: widget.childrenDelegate,
                 padEnds: widget.padEnds,
+                allowImplicitScrolling: widget.allowImplicitScrolling,
               ),
             ],
           );
@@ -447,6 +506,15 @@ class _PageViewState<T extends HorizontalDragGestureRecognizer>
           value: widget.allowImplicitScrolling,
           ifTrue: 'allow implicit scrolling',
         ),
+      )
+      ..add(
+        DiagnosticsProperty<ScrollCacheExtent>(
+          'scrollCacheExtent',
+          widget.scrollCacheExtent,
+          defaultValue: ScrollCacheExtent.viewport(
+            widget.allowImplicitScrolling ? 1.0 : 0.0,
+          ),
+        ),
       );
   }
 }

lib/common/widgets/flutter/page/scrollable.dart

@@ -948,9 +948,6 @@ class ScrollableState<T extends HorizontalDragGestureRecognizer>
   void _receivedPointerSignal(PointerSignalEvent event) {
     if (event is PointerScrollEvent && _position != null) {
       if (_physics != null && !_physics!.shouldAcceptUserOffset(position)) {
-        // The handler won't use the `event`, so allow the platform to trigger
-        // any default native actions.
-        event.respond(allowPlatformDefault: true);
         return;
       }
       final double delta = _pointerSignalEventDelta(event);
@@ -965,9 +962,6 @@ class ScrollableState<T extends HorizontalDragGestureRecognizer>
         );
         return;
       }
-      // The `event` won't result in a scroll, so allow the platform to trigger
-      // any default native actions.
-      event.respond(allowPlatformDefault: true);
     } else if (event is PointerScrollInertiaCancelEvent) {
       position.pointerScroll(0);
       // Don't use the pointer signal resolver, all hit-tested scrollables should stop.
@@ -976,12 +970,16 @@ class ScrollableState<T extends HorizontalDragGestureRecognizer>
 
   void _handlePointerScroll(PointerEvent event) {
     assert(event is PointerScrollEvent);
-    final double delta = _pointerSignalEventDelta(event as PointerScrollEvent);
+    final scrollEvent = event as PointerScrollEvent;
+    final double delta = _pointerSignalEventDelta(scrollEvent);
     final double targetScrollOffset = _targetScrollOffsetForPointerScroll(
       delta,
     );
     if (delta != 0.0 && targetScrollOffset != position.pixels) {
       position.pointerScroll(delta);
+      // Tell engine this scrollable handled the event.
+      // This prevents parent page from scrolling when nested scrollables exist.
+      scrollEvent.respond(allowPlatformDefault: false);
     }
   }