Add configurable hitTestBehavior to Scrollable (#146403)

This PR adds `hitTestBehavior` to Scrollable as a configurable member.

- flutter/flutter#146401

packages/flutter/lib/src/widgets/list_wheel_scroll_view.dart

@@ -425,6 +425,7 @@ class _FixedExtentScrollable extends Scrollable {
     required super.viewportBuilder,
     super.restorationId,
     super.scrollBehavior,
+    super.hitTestBehavior,
   });
 
   final double itemExtent;
@@ -570,6 +571,7 @@ class ListWheelScrollView extends StatefulWidget {
     this.onSelectedItemChanged,
     this.renderChildrenOutsideViewport = false,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.restorationId,
     this.scrollBehavior,
     required List<Widget> children,
@@ -603,6 +605,7 @@ class ListWheelScrollView extends StatefulWidget {
     this.onSelectedItemChanged,
     this.renderChildrenOutsideViewport = false,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.restorationId,
     this.scrollBehavior,
     required this.childDelegate,
@@ -689,6 +692,11 @@ class ListWheelScrollView extends StatefulWidget {
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// Defaults to [HitTestBehavior.opaque].
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.widgets.scrollable.restorationId}
   final String? restorationId;
 
@@ -754,6 +762,7 @@ class _ListWheelScrollViewState extends State<ListWheelScrollView> {
         physics: widget.physics,
         itemExtent: widget.itemExtent,
         restorationId: widget.restorationId,
+        hitTestBehavior: widget.hitTestBehavior,
         scrollBehavior: widget.scrollBehavior ?? ScrollConfiguration.of(context).copyWith(scrollbars: false),
         viewportBuilder: (BuildContext context, ViewportOffset offset) {
           return ListWheelViewport(

packages/flutter/lib/src/widgets/nested_scroll_view.dart

@@ -188,6 +188,7 @@ class NestedScrollView extends StatefulWidget {
     this.dragStartBehavior = DragStartBehavior.start,
     this.floatHeaderSlivers = false,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.restorationId,
     this.scrollBehavior,
   });
@@ -297,6 +298,11 @@ class NestedScrollView extends StatefulWidget {
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// Defaults to [HitTestBehavior.opaque].
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.widgets.scrollable.restorationId}
   final String? restorationId;
 
@@ -489,6 +495,7 @@ class NestedScrollViewState extends State<NestedScrollView> {
             handle: _absorberHandle,
             clipBehavior: widget.clipBehavior,
             restorationId: widget.restorationId,
+            hitTestBehavior: widget.hitTestBehavior,
           );
         },
       ),
@@ -506,6 +513,7 @@ class _NestedScrollViewCustomScrollView extends CustomScrollView {
     required super.slivers,
     required this.handle,
     required super.clipBehavior,
+    super.hitTestBehavior,
     super.dragStartBehavior,
     super.restorationId,
   });

packages/flutter/lib/src/widgets/page_view.dart

@@ -649,6 +649,7 @@ class PageView extends StatefulWidget {
     this.allowImplicitScrolling = false,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
   }) : childrenDelegate = SliverChildListDelegate(children);
@@ -693,6 +694,7 @@ class PageView extends StatefulWidget {
     this.allowImplicitScrolling = false,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
   }) : childrenDelegate = SliverChildBuilderDelegate(
@@ -725,6 +727,7 @@ class PageView extends StatefulWidget {
     this.allowImplicitScrolling = false,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.scrollBehavior,
     this.padEnds = true,
   });
@@ -812,6 +815,11 @@ class PageView extends StatefulWidget {
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// Defaults to [HitTestBehavior.opaque].
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.widgets.shadow.scrollBehavior}
   ///
   /// [ScrollBehavior]s also provide [ScrollPhysics]. If an explicit
@@ -915,6 +923,7 @@ class _PageViewState extends State<PageView> {
         controller: _controller,
         physics: physics,
         restorationId: widget.restorationId,
+        hitTestBehavior: widget.hitTestBehavior,
         scrollBehavior: widget.scrollBehavior ?? ScrollConfiguration.of(context).copyWith(scrollbars: false),
         viewportBuilder: (BuildContext context, ViewportOffset position) {
           return Viewport(

packages/flutter/lib/src/widgets/scroll_view.dart

@@ -114,6 +114,7 @@ abstract class ScrollView extends StatelessWidget {
     this.keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual,
     this.restorationId,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
   }) : assert(
          !(controller != null && (primary ?? false)),
          'Primary ScrollViews obtain their ScrollController via inheritance '
@@ -377,6 +378,11 @@ abstract class ScrollView extends StatelessWidget {
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// Defaults to [HitTestBehavior.opaque].
+  final HitTestBehavior hitTestBehavior;
+
   /// Returns the [AxisDirection] in which the scroll view scrolls.
   ///
   /// Combines the [scrollDirection] with the [reverse] boolean to obtain the
@@ -476,6 +482,7 @@ abstract class ScrollView extends StatelessWidget {
       scrollBehavior: scrollBehavior,
       semanticChildCount: semanticChildCount,
       restorationId: restorationId,
+      hitTestBehavior: hitTestBehavior,
       viewportBuilder: (BuildContext context, ViewportOffset offset) {
         return buildViewport(context, offset, axisDirection, slivers);
       },
@@ -665,6 +672,7 @@ class CustomScrollView extends ScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   });
 
   /// The slivers to place inside the viewport.
@@ -804,6 +812,7 @@ abstract class BoxScrollView extends ScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   });
 
   /// The amount of space by which to inset the children.
@@ -1240,6 +1249,7 @@ class ListView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : assert(
          (itemExtent == null && prototypeItem == null) ||
          (itemExtent == null && itemExtentBuilder == null) ||
@@ -1318,6 +1328,7 @@ class ListView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : assert(itemCount == null || itemCount >= 0),
        assert(semanticChildCount == null || semanticChildCount <= itemCount!),
        assert(
@@ -1410,6 +1421,7 @@ class ListView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : assert(itemCount >= 0),
        itemExtent = null,
        itemExtentBuilder = null,
@@ -1465,6 +1477,7 @@ class ListView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : assert(
          (itemExtent == null && prototypeItem == null) ||
          (itemExtent == null && itemExtentBuilder == null) ||
@@ -1856,6 +1869,7 @@ class GridView extends BoxScrollView {
     super.clipBehavior,
     super.keyboardDismissBehavior,
     super.restorationId,
+    super.hitTestBehavior,
   }) : childrenDelegate = SliverChildListDelegate(
          children,
          addAutomaticKeepAlives: addAutomaticKeepAlives,
@@ -1912,6 +1926,7 @@ class GridView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : childrenDelegate = SliverChildBuilderDelegate(
          itemBuilder,
          findChildIndexCallback: findChildIndexCallback,
@@ -1946,6 +1961,7 @@ class GridView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   });
 
   /// Creates a scrollable, 2D array of widgets with a fixed number of tiles in
@@ -1985,6 +2001,7 @@ class GridView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : gridDelegate = SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: crossAxisCount,
          mainAxisSpacing: mainAxisSpacing,
@@ -2038,6 +2055,7 @@ class GridView extends BoxScrollView {
     super.keyboardDismissBehavior,
     super.restorationId,
     super.clipBehavior,
+    super.hitTestBehavior,
   }) : gridDelegate = SliverGridDelegateWithMaxCrossAxisExtent(
          maxCrossAxisExtent: maxCrossAxisExtent,
          mainAxisSpacing: mainAxisSpacing,

packages/flutter/lib/src/widgets/scrollable.dart

@@ -116,6 +116,7 @@ class Scrollable extends StatefulWidget {
     this.restorationId,
     this.scrollBehavior,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
   }) : assert(semanticChildCount == null || semanticChildCount >= 0);
 
   /// {@template flutter.widgets.Scrollable.axisDirection}
@@ -225,6 +226,18 @@ class Scrollable extends StatefulWidget {
   ///    exclusion.
   final bool excludeFromSemantics;
 
+  /// {@template flutter.widgets.scrollable.hitTestBehavior}
+  /// Defines the behavior of gesture detector used in this [Scrollable].
+  ///
+  /// This defaults to [HitTestBehavior.opaque] which means it prevents targets
+  /// behind this [Scrollable] from receiving events.
+  /// {@endtemplate}
+  ///
+  /// See also:
+  ///
+  ///  * [HitTestBehavior], for an explanation on different behaviors.
+  final HitTestBehavior hitTestBehavior;
+
   /// The number of children that will contribute semantic information.
   ///
   /// The value will be null if the number of children is unknown or unbounded.
@@ -971,7 +984,7 @@ class ScrollableState extends State<Scrollable> with TickerProviderStateMixin, R
         child: RawGestureDetector(
           key: _gestureDetectorKey,
           gestures: _gestureRecognizers,
-          behavior: HitTestBehavior.opaque,
+          behavior: widget.hitTestBehavior,
           excludeFromSemantics: widget.excludeFromSemantics,
           child: Semantics(
             explicitChildNodes: !widget.excludeFromSemantics,
@@ -1732,6 +1745,7 @@ class TwoDimensionalScrollable extends StatefulWidget {
     this.excludeFromSemantics = false,
     this.diagonalDragBehavior = DiagonalDragBehavior.none,
     this.dragStartBehavior = DragStartBehavior.start,
+    this.hitTestBehavior = HitTestBehavior.opaque,
   });
 
   /// How scrolling gestures should lock to one axis, or allow free movement
@@ -1778,6 +1792,11 @@ class TwoDimensionalScrollable extends StatefulWidget {
   /// This value applies to both axes.
   final bool excludeFromSemantics;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// This value applies to both axes.
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.widgets.scrollable.dragStartBehavior}
   ///
   /// This value applies in both axes.
@@ -1980,6 +1999,7 @@ class TwoDimensionalScrollableState extends State<TwoDimensionalScrollable> {
         restorationId: 'OuterVerticalTwoDimensionalScrollable',
         dragStartBehavior: widget.dragStartBehavior,
         diagonalDragBehavior: widget.diagonalDragBehavior,
+        hitTestBehavior: widget.hitTestBehavior,
         viewportBuilder: (BuildContext context, ViewportOffset verticalOffset) {
           return _HorizontalInnerDimension(
             key: _horizontalInnerScrollableKey,
@@ -1996,6 +2016,7 @@ class TwoDimensionalScrollableState extends State<TwoDimensionalScrollable> {
             restorationId: 'InnerHorizontalTwoDimensionalScrollable',
             dragStartBehavior: widget.dragStartBehavior,
             diagonalDragBehavior: widget.diagonalDragBehavior,
+            hitTestBehavior: widget.hitTestBehavior,
             viewportBuilder: (BuildContext context, ViewportOffset horizontalOffset) {
               return widget.viewportBuilder(context, verticalOffset, horizontalOffset);
             },
@@ -2051,6 +2072,7 @@ class _VerticalOuterDimension extends Scrollable {
     super.excludeFromSemantics,
     super.dragStartBehavior,
     super.restorationId,
+    super.hitTestBehavior,
     this.diagonalDragBehavior = DiagonalDragBehavior.none,
   }) : assert(axisDirection == AxisDirection.up || axisDirection == AxisDirection.down);
 
@@ -2315,6 +2337,7 @@ class _HorizontalInnerDimension extends Scrollable {
     super.excludeFromSemantics,
     super.dragStartBehavior,
     super.restorationId,
+    super.hitTestBehavior,
     this.diagonalDragBehavior = DiagonalDragBehavior.none,
   }) : assert(axisDirection == AxisDirection.left || axisDirection == AxisDirection.right);
 

packages/flutter/lib/src/widgets/single_child_scroll_view.dart

@@ -151,6 +151,7 @@ class SingleChildScrollView extends StatelessWidget {
     this.child,
     this.dragStartBehavior = DragStartBehavior.start,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
     this.restorationId,
     this.keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual,
   }) : assert(
@@ -218,6 +219,11 @@ class SingleChildScrollView extends StatelessWidget {
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// Defaults to [HitTestBehavior.opaque].
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.widgets.scrollable.restorationId}
   final String? restorationId;
 
@@ -249,6 +255,7 @@ class SingleChildScrollView extends StatelessWidget {
       physics: physics,
       restorationId: restorationId,
       clipBehavior: clipBehavior,
+      hitTestBehavior: hitTestBehavior,
       viewportBuilder: (BuildContext context, ViewportOffset offset) {
         return _SingleChildViewport(
           axisDirection: axisDirection,

packages/flutter/lib/src/widgets/two_dimensional_scroll_view.dart

@@ -62,6 +62,7 @@ abstract class TwoDimensionalScrollView extends StatelessWidget {
     this.dragStartBehavior = DragStartBehavior.start,
     this.keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual,
     this.clipBehavior = Clip.hardEdge,
+    this.hitTestBehavior = HitTestBehavior.opaque,
   });
 
   /// A delegate that provides the children for the [TwoDimensionalScrollView].
@@ -107,6 +108,11 @@ abstract class TwoDimensionalScrollView extends StatelessWidget {
   /// {@macro flutter.widgets.scroll_view.keyboardDismissBehavior}
   final ScrollViewKeyboardDismissBehavior keyboardDismissBehavior;
 
+  /// {@macro flutter.widgets.scrollable.hitTestBehavior}
+  ///
+  /// This value applies to both axes.
+  final HitTestBehavior hitTestBehavior;
+
   /// {@macro flutter.material.Material.clipBehavior}
   ///
   /// Defaults to [Clip.hardEdge].
@@ -172,6 +178,7 @@ abstract class TwoDimensionalScrollView extends StatelessWidget {
       diagonalDragBehavior: diagonalDragBehavior,
       viewportBuilder: buildViewport,
       dragStartBehavior: dragStartBehavior,
+      hitTestBehavior: hitTestBehavior,
     );
 
     final Widget scrollableResult = effectivePrimary