🚀 Expose scrollControlDisabledMaxHeightRatio to the modal bottom sheet (#129688)

Adding the `scrollControlDisabledMaxHeightRatio` parameter for modal bottom sheet widgets, and using the default value `9.0 / 16.0` to avoid breaking.

Resolves #129690.

packages/flutter/lib/src/material/bottom_sheet.dart

@@ -26,6 +26,7 @@ const Duration _bottomSheetExitDuration = Duration(milliseconds: 200);
 const Curve _modalBottomSheetCurve = decelerateEasing;
 const double _minFlingVelocity = 700.0;
 const double _closeProgressThreshold = 0.5;
+const double _defaultScrollControlDisabledMaxHeightRatio = 9.0 / 16.0;
 
 /// A callback for when the user begins dragging the bottom sheet.
 ///
@@ -471,24 +472,26 @@ class _DragHandle extends StatelessWidget {
 }
 
 class _BottomSheetLayoutWithSizeListener extends SingleChildRenderObjectWidget {
-
   const _BottomSheetLayoutWithSizeListener({
+    required this.onChildSizeChanged,
     required this.animationValue,
     required this.isScrollControlled,
-    required this.onChildSizeChanged,
+    required this.scrollControlDisabledMaxHeightRatio,
     super.child,
   });
 
+  final _SizeChangeCallback<Size> onChildSizeChanged;
   final double animationValue;
   final bool isScrollControlled;
-  final _SizeChangeCallback<Size> onChildSizeChanged;
+  final double scrollControlDisabledMaxHeightRatio;
 
   @override
   _RenderBottomSheetLayoutWithSizeListener createRenderObject(BuildContext context) {
     return _RenderBottomSheetLayoutWithSizeListener(
+      onChildSizeChanged: onChildSizeChanged,
       animationValue: animationValue,
       isScrollControlled: isScrollControlled,
-      onChildSizeChanged: onChildSizeChanged,
+      scrollControlDisabledMaxHeightRatio: scrollControlDisabledMaxHeightRatio,
     );
   }
 
@@ -497,6 +500,7 @@ class _BottomSheetLayoutWithSizeListener extends SingleChildRenderObjectWidget {
     renderObject.onChildSizeChanged = onChildSizeChanged;
     renderObject.animationValue = animationValue;
     renderObject.isScrollControlled = isScrollControlled;
+    renderObject.scrollControlDisabledMaxHeightRatio = scrollControlDisabledMaxHeightRatio;
   }
 }
 
@@ -506,9 +510,11 @@ class _RenderBottomSheetLayoutWithSizeListener extends RenderShiftedBox {
     required _SizeChangeCallback<Size> onChildSizeChanged,
     required double animationValue,
     required bool isScrollControlled,
-  }) : _animationValue = animationValue,
+    required double scrollControlDisabledMaxHeightRatio,
+  }) : _onChildSizeChanged = onChildSizeChanged,
+       _animationValue = animationValue,
        _isScrollControlled = isScrollControlled,
-       _onChildSizeChanged = onChildSizeChanged,
+       _scrollControlDisabledMaxHeightRatio = scrollControlDisabledMaxHeightRatio,
        super(child);
 
   Size _lastSize = Size.zero;
@@ -546,6 +552,17 @@ class _RenderBottomSheetLayoutWithSizeListener extends RenderShiftedBox {
     markNeedsLayout();
   }
 
+  double get scrollControlDisabledMaxHeightRatio => _scrollControlDisabledMaxHeightRatio;
+  double _scrollControlDisabledMaxHeightRatio;
+  set scrollControlDisabledMaxHeightRatio(double newValue) {
+    if (_scrollControlDisabledMaxHeightRatio == newValue) {
+      return;
+    }
+
+    _scrollControlDisabledMaxHeightRatio = newValue;
+    markNeedsLayout();
+  }
+
   Size _getSize(BoxConstraints constraints) {
     return constraints.constrain(constraints.biggest);
   }
@@ -591,13 +608,13 @@ class _RenderBottomSheetLayoutWithSizeListener extends RenderShiftedBox {
     return _getSize(constraints);
   }
 
-    BoxConstraints _getConstraintsForChild(BoxConstraints constraints) {
+  BoxConstraints _getConstraintsForChild(BoxConstraints constraints) {
     return BoxConstraints(
       minWidth: constraints.maxWidth,
       maxWidth: constraints.maxWidth,
       maxHeight: isScrollControlled
-        ? constraints.maxHeight
-        : constraints.maxHeight * 9.0 / 16.0,
+          ? constraints.maxHeight
+          : constraints.maxHeight * scrollControlDisabledMaxHeightRatio,
     );
   }
 
@@ -634,12 +651,14 @@ class _ModalBottomSheet<T> extends StatefulWidget {
     this.clipBehavior,
     this.constraints,
     this.isScrollControlled = false,
+    this.scrollControlDisabledMaxHeightRatio = _defaultScrollControlDisabledMaxHeightRatio,
     this.enableDrag = true,
     this.showDragHandle = false,
   });
 
   final ModalBottomSheetRoute<T> route;
   final bool isScrollControlled;
+  final double scrollControlDisabledMaxHeightRatio;
   final Color? backgroundColor;
   final double? elevation;
   final ShapeBorder? shape;
@@ -730,6 +749,7 @@ class _ModalBottomSheetState<T> extends State<_ModalBottomSheet<T>> {
               },
               animationValue: animationValue,
               isScrollControlled: widget.isScrollControlled,
+              scrollControlDisabledMaxHeightRatio: widget.scrollControlDisabledMaxHeightRatio,
               child: child,
             ),
           ),
@@ -815,6 +835,7 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
     this.enableDrag = true,
     this.showDragHandle,
     required this.isScrollControlled,
+    this.scrollControlDisabledMaxHeightRatio = _defaultScrollControlDisabledMaxHeightRatio,
     super.settings,
     this.transitionAnimationController,
     this.anchorPoint,
@@ -842,6 +863,13 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
   /// to have the bottom sheet be draggable.
   final bool isScrollControlled;
 
+  /// The max height constraint ratio for the bottom sheet
+  /// when [isScrollControlled] set to false,
+  /// no ratio will be applied when [isScrollControlled] set to true.
+  ///
+  /// Defaults to 9 / 16.
+  final double scrollControlDisabledMaxHeightRatio;
+
   /// The bottom sheet's background color.
   ///
   /// Defines the bottom sheet's [Material.color].
@@ -1026,6 +1054,7 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
             clipBehavior: clipBehavior,
             constraints: constraints,
             isScrollControlled: isScrollControlled,
+            scrollControlDisabledMaxHeightRatio: scrollControlDisabledMaxHeightRatio,
             enableDrag: enableDrag,
             showDragHandle: showDragHandle ?? (enableDrag && (sheetTheme.showDragHandle ?? false)),
           );
@@ -1192,6 +1221,7 @@ Future<T?> showModalBottomSheet<T>({
   BoxConstraints? constraints,
   Color? barrierColor,
   bool isScrollControlled = false,
+  double scrollControlDisabledMaxHeightRatio = _defaultScrollControlDisabledMaxHeightRatio,
   bool useRootNavigator = false,
   bool isDismissible = true,
   bool enableDrag = true,
@@ -1210,6 +1240,7 @@ Future<T?> showModalBottomSheet<T>({
     builder: builder,
     capturedThemes: InheritedTheme.capture(from: context, to: navigator.context),
     isScrollControlled: isScrollControlled,
+    scrollControlDisabledMaxHeightRatio: scrollControlDisabledMaxHeightRatio,
     barrierLabel: barrierLabel ?? localizations.scrimLabel,
     barrierOnTapHint: localizations.scrimOnTapHint(localizations.bottomSheetLabel),
     backgroundColor: backgroundColor,

packages/flutter/test/material/bottom_sheet_test.dart

@@ -1789,7 +1789,7 @@ void main() {
   });
 
   group('constraints', () {
-      testWidgets('default constraints are max width 640 in material 3', (WidgetTester tester) async {
+    testWidgets('default constraints are max width 640 in material 3', (WidgetTester tester) async {
       await tester.pumpWidget(
         MaterialApp(
           theme: ThemeData.light(useMaterial3: true),
@@ -2045,6 +2045,58 @@ void main() {
       );
     });
 
+    group('scrollControlDisabledMaxHeightRatio', () {
+      Future<void> test(
+        WidgetTester tester,
+        bool isScrollControlled,
+        double scrollControlDisabledMaxHeightRatio,
+      ) async {
+        await tester.pumpWidget(
+          MaterialApp(
+            home: Scaffold(
+              body: Builder(builder: (BuildContext context) {
+                return Center(
+                  child: ElevatedButton(
+                    child: const Text('Press me'),
+                    onPressed: () {
+                      showModalBottomSheet<void>(
+                        context: context,
+                        isScrollControlled: isScrollControlled,
+                        scrollControlDisabledMaxHeightRatio: scrollControlDisabledMaxHeightRatio,
+                        builder: (BuildContext context) => const SizedBox.expand(
+                          child: Text('BottomSheet'),
+                        ),
+                      );
+                    },
+                  ),
+                );
+              }),
+            ),
+          ),
+        );
+        await tester.tap(find.text('Press me'));
+        await tester.pumpAndSettle();
+        expect(
+          tester.getRect(find.text('BottomSheet')),
+          Rect.fromLTRB(
+            80,
+            600 * (isScrollControlled ? 0 : (1 - scrollControlDisabledMaxHeightRatio)),
+            720,
+            600,
+          ),
+        );
+      }
+
+      testWidgets('works at 9 / 16', (WidgetTester tester) {
+        return test(tester, false, 9.0 / 16.0);
+      });
+      testWidgets('works at 8 / 16', (WidgetTester tester) {
+        return test(tester, false, 8.0 / 16.0);
+      });
+      testWidgets('works at isScrollControlled', (WidgetTester tester) {
+        return test(tester, true, 8.0 / 16.0);
+      });
+    });
   });
 
   group('showModalBottomSheet modalBarrierDismissLabel', () {