Add `AnimationStyle` to `showBottomSheet` and `showModalBottomSheet` (#145536)

fixes [Introduce animation customizable with `AnimationStyle` to `BottomSheet`](https://github.com/flutter/flutter/issues/145532)

### Default bottom sheet animation
![00-ezgif com-video-to-gif-converter](https://github.com/flutter/flutter/assets/48603081/a295b002-b310-4dea-8bc4-23b1d299748c)

### Custom bottom sheet animation
![01-ezgif com-video-to-gif-converter](https://github.com/flutter/flutter/assets/48603081/8c5c3d5f-e67d-4ed5-880d-f17d262087e1)

### No bottom sheet animation
![02-ezgif com-video-to-gif-converter](https://github.com/flutter/flutter/assets/48603081/872409d8-8a8d-4db9-b95b-7f96a62cdffc)

examples/api/lib/material/bottom_sheet/show_bottom_sheet.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+
+/// Flutter code sample for [showBottomSheet].
+
+void main() => runApp(const BottomSheetExampleApp());
+
+class BottomSheetExampleApp extends StatelessWidget {
+  const BottomSheetExampleApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(title: const Text('Bottom Sheet Sample')),
+        body: const BottomSheetExample(),
+      ),
+    );
+  }
+}
+
+enum AnimationStyles { defaultStyle, custom, none }
+const List<(AnimationStyles, String)> animationStyleSegments = <(AnimationStyles, String)>[
+  (AnimationStyles.defaultStyle, 'Default'),
+  (AnimationStyles.custom, 'Custom'),
+  (AnimationStyles.none, 'None'),
+];
+
+class BottomSheetExample extends StatefulWidget {
+  const BottomSheetExample({super.key});
+
+  @override
+  State<BottomSheetExample> createState() => _BottomSheetExampleState();
+}
+
+class _BottomSheetExampleState extends State<BottomSheetExample> {
+  Set<AnimationStyles> _animationStyleSelection = <AnimationStyles>{AnimationStyles.defaultStyle};
+  AnimationStyle? _animationStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: <Widget>[
+          SegmentedButton<AnimationStyles>(
+            selected: _animationStyleSelection,
+            onSelectionChanged: (Set<AnimationStyles> styles) {
+              setState(() {
+                _animationStyle = switch (styles.first) {
+                  AnimationStyles.defaultStyle => null,
+                  AnimationStyles.custom => AnimationStyle(
+                    duration: const Duration(seconds: 3),
+                    reverseDuration: const Duration(seconds: 1),
+                  ),
+                  AnimationStyles.none => AnimationStyle.noAnimation,
+                };
+                _animationStyleSelection = styles;
+              });
+            },
+            segments: animationStyleSegments
+              .map<ButtonSegment<AnimationStyles>>(((AnimationStyles, String) shirt) {
+                return ButtonSegment<AnimationStyles>(value: shirt.$1, label: Text(shirt.$2));
+              })
+              .toList(),
+          ),
+          const SizedBox(height: 10),
+          ElevatedButton(
+            child: const Text('showBottomSheet'),
+            onPressed: () {
+              showBottomSheet(
+                context: context,
+                sheetAnimationStyle: _animationStyle,
+                builder: (BuildContext context) {
+                  return SizedBox.expand(
+                    child: Center(
+                      child: Column(
+                        mainAxisAlignment: MainAxisAlignment.center,
+                        mainAxisSize: MainAxisSize.min,
+                        children: <Widget>[
+                          const Text('Bottom sheet'),
+                          ElevatedButton(
+                            child: const Text('Close'),
+                            onPressed: () => Navigator.pop(context),
+                          ),
+                        ],
+                      ),
+                    ),
+                  );
+                },
+              );
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}

examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.2.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+
+/// Flutter code sample for [showModalBottomSheet].
+
+void main() => runApp(const ModalBottomSheetApp());
+
+class ModalBottomSheetApp extends StatelessWidget {
+  const ModalBottomSheetApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(title: const Text('Modal Bottom Sheet Sample')),
+        body: const ModalBottomSheetExample(),
+      ),
+    );
+  }
+}
+
+enum AnimationStyles { defaultStyle, custom, none }
+const List<(AnimationStyles, String)> animationStyleSegments = <(AnimationStyles, String)>[
+  (AnimationStyles.defaultStyle, 'Default'),
+  (AnimationStyles.custom, 'Custom'),
+  (AnimationStyles.none, 'None'),
+];
+
+class ModalBottomSheetExample extends StatefulWidget {
+  const ModalBottomSheetExample({super.key});
+
+  @override
+  State<ModalBottomSheetExample> createState() => _ModalBottomSheetExampleState();
+}
+
+class _ModalBottomSheetExampleState extends State<ModalBottomSheetExample> {
+  Set<AnimationStyles> _animationStyleSelection = <AnimationStyles>{AnimationStyles.defaultStyle};
+  AnimationStyle? _animationStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: <Widget>[
+          SegmentedButton<AnimationStyles>(
+            selected: _animationStyleSelection,
+            onSelectionChanged: (Set<AnimationStyles> styles) {
+              setState(() {
+                _animationStyle = switch (styles.first) {
+                  AnimationStyles.defaultStyle => null,
+                  AnimationStyles.custom => AnimationStyle(
+                    duration: const Duration(seconds: 3),
+                    reverseDuration: const Duration(seconds: 1),
+                  ),
+                  AnimationStyles.none => AnimationStyle.noAnimation,
+                };
+                _animationStyleSelection = styles;
+              });
+            },
+            segments: animationStyleSegments
+              .map<ButtonSegment<AnimationStyles>>(((AnimationStyles, String) shirt) {
+                return ButtonSegment<AnimationStyles>(value: shirt.$1, label: Text(shirt.$2));
+              })
+              .toList(),
+          ),
+          const SizedBox(height: 10),
+          ElevatedButton(
+            child: const Text('showModalBottomSheet'),
+            onPressed: () {
+              showModalBottomSheet<void>(
+                context: context,
+                sheetAnimationStyle: _animationStyle,
+                builder: (BuildContext context) {
+                  return SizedBox.expand(
+                    child: Center(
+                      child: Column(
+                        mainAxisAlignment: MainAxisAlignment.center,
+                        mainAxisSize: MainAxisSize.min,
+                        children: <Widget>[
+                          const Text('Modal bottom sheet'),
+                          ElevatedButton(
+                            child: const Text('Close'),
+                            onPressed: () => Navigator.pop(context),
+                          ),
+                        ],
+                      ),
+                    ),
+                  );
+                },
+              );
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}

examples/api/lib/material/scaffold/scaffold_messenger_state.show_snack_bar.2.dart

@@ -34,7 +34,7 @@ class SnackBarExample extends StatefulWidget {
 }
 
 class _SnackBarExampleState extends State<SnackBarExample> {
-  final Set<AnimationStyles> _animationStyleSelection = <AnimationStyles>{AnimationStyles.defaultStyle};
+  Set<AnimationStyles> _animationStyleSelection = <AnimationStyles>{AnimationStyles.defaultStyle};
   AnimationStyle? _animationStyle;
 
   @override
@@ -57,6 +57,7 @@ class _SnackBarExampleState extends State<SnackBarExample> {
                     ),
                     AnimationStyles.none => AnimationStyle.noAnimation,
                   };
+                  _animationStyleSelection = styles;
                 });
               },
               segments: animationStyleSegments

examples/api/lib/material/scaffold/scaffold_state.show_bottom_sheet.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+
+/// Flutter code sample for [ScaffoldState.showBottomSheet].
+
+void main() => runApp(const ShowBottomSheetExampleApp());
+
+class ShowBottomSheetExampleApp extends StatelessWidget {
+  const ShowBottomSheetExampleApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(title: const Text('ScaffoldState BottomSheet Sample')),
+        body: const ShowBottomSheetExample(),
+      ),
+    );
+  }
+}
+
+enum AnimationStyles { defaultStyle, custom, none }
+const List<(AnimationStyles, String)> animationStyleSegments = <(AnimationStyles, String)>[
+  (AnimationStyles.defaultStyle, 'Default'),
+  (AnimationStyles.custom, 'Custom'),
+  (AnimationStyles.none, 'None'),
+];
+
+class ShowBottomSheetExample extends StatefulWidget {
+  const ShowBottomSheetExample({super.key});
+
+  @override
+  State<ShowBottomSheetExample> createState() => _ShowBottomSheetExampleState();
+}
+
+class _ShowBottomSheetExampleState extends State<ShowBottomSheetExample> {
+  Set<AnimationStyles> _animationStyleSelection = <AnimationStyles>{AnimationStyles.defaultStyle};
+  AnimationStyle? _animationStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: <Widget>[
+          SegmentedButton<AnimationStyles>(
+            selected: _animationStyleSelection,
+            onSelectionChanged: (Set<AnimationStyles> styles) {
+              setState(() {
+                _animationStyle = switch (styles.first) {
+                  AnimationStyles.defaultStyle => null,
+                  AnimationStyles.custom => AnimationStyle(
+                    duration: const Duration(seconds: 3),
+                    reverseDuration: const Duration(seconds: 1),
+                  ),
+                  AnimationStyles.none => AnimationStyle.noAnimation,
+                };
+                _animationStyleSelection = styles;
+              });
+            },
+            segments: animationStyleSegments
+              .map<ButtonSegment<AnimationStyles>>(((AnimationStyles, String) shirt) {
+                return ButtonSegment<AnimationStyles>(value: shirt.$1, label: Text(shirt.$2));
+              })
+              .toList(),
+          ),
+          const SizedBox(height: 10),
+          ElevatedButton(
+            child: const Text('showBottomSheet'),
+            onPressed: () {
+              Scaffold.of(context).showBottomSheet(
+                sheetAnimationStyle: _animationStyle,
+                (BuildContext context) {
+                  return SizedBox(
+                    height: 200,
+                    child: Center(
+                      child: Column(
+                        mainAxisAlignment: MainAxisAlignment.center,
+                        mainAxisSize: MainAxisSize.min,
+                        children: <Widget>[
+                          const Text('BottomSheet'),
+                          ElevatedButton(
+                            child: const Text('Close'),
+                            onPressed: () {
+                              Navigator.pop(context);
+                            },
+                          ),
+                        ],
+                      ),
+                    ),
+                  );
+                },
+              );
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}

examples/api/test/material/bottom_sheet/show_bottom_sheet.0_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/bottom_sheet/show_bottom_sheet.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Bottom sheet animation can be customized using AnimationStyle', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.BottomSheetExampleApp(),
+    );
+
+    // Show the bottom sheet with default animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(178.0, 0.1));
+
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(56.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select custom animation style.
+    await tester.tap(find.text('Custom'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with custom animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(178.0, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(56.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select no animation style.
+    await tester.tap(find.text('None'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with no animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(56.0));
+  });
+}

examples/api/test/material/bottom_sheet/show_modal_bottom_sheet.2_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/bottom_sheet/show_modal_bottom_sheet.2.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Modal bottom sheet animation can be customized using AnimationStyle', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.ModalBottomSheetApp(),
+    );
+
+    // Show the bottom sheet with default animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showModalBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(262.5));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select custom animation style.
+    await tester.tap(find.text('Custom'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with custom animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showModalBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(262.5));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select no animation style.
+    await tester.tap(find.text('None'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with no animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showModalBottomSheet'));
+    await tester.pump();
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(262.5));
+  });
+}

examples/api/test/material/scaffold/scaffold_state.show_bottom_sheet.1_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/scaffold/scaffold_state.show_bottom_sheet.1.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Scaffold showBottomSheet animation can be customized using AnimationStyle', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.ShowBottomSheetExampleApp(),
+    );
+
+    // Show the bottom sheet with default animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(444.8, 0.1));
+
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(400.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select custom animation style.
+    await tester.tap(find.text('Custom'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with custom animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, closeTo(444.8, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 1500));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(400.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'Close'));
+    await tester.pumpAndSettle();
+
+    // Select no animation style.
+    await tester.tap(find.text('None'));
+    await tester.pumpAndSettle();
+
+    // Show the bottom sheet with no animation style.
+    await tester.tap(find.widgetWithText(ElevatedButton, 'showBottomSheet'));
+    await tester.pump();
+    expect(tester.getTopLeft(find.byType(BottomSheet)).dy, equals(400.0));
+  });
+}

packages/flutter/lib/src/animation/animation_style.dart

@@ -13,6 +13,9 @@ import 'tween.dart';
 /// - [ExpansionTile]
 /// - [MaterialApp]
 /// - [PopupMenuButton]
+/// - [ScaffoldMessengerState.showSnackBar]
+/// - [showBottomSheet]
+/// - [showModalBottomSheet]
 ///
 /// If [duration] and [reverseDuration] are set to [Duration.zero], the
 /// corresponding animation will be disabled.

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

@@ -237,10 +237,13 @@ class BottomSheet extends StatefulWidget {
   /// This API available as a convenience for a Material compliant bottom sheet
   /// animation. If alternative animation durations are required, a different
   /// animation controller could be provided.
-  static AnimationController createAnimationController(TickerProvider vsync) {
+  static AnimationController createAnimationController(
+    TickerProvider vsync,
+    { AnimationStyle? sheetAnimationStyle }
+  ) {
     return AnimationController(
-      duration: _bottomSheetEnterDuration,
-      reverseDuration: _bottomSheetExitDuration,
+      duration: sheetAnimationStyle?.duration ?? _bottomSheetEnterDuration,
+      reverseDuration: sheetAnimationStyle?.reverseDuration ?? _bottomSheetExitDuration,
       debugLabel: 'BottomSheet',
       vsync: vsync,
     );
@@ -846,6 +849,7 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
     this.transitionAnimationController,
     this.anchorPoint,
     this.useSafeArea = false,
+    this.sheetAnimationStyle,
   });
 
   /// A builder for the contents of the sheet.
@@ -992,6 +996,20 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
   /// The default is false.
   final bool useSafeArea;
 
+  /// Used to override the modal bottom sheet animation duration and reverse
+  /// animation duration.
+  ///
+  /// If [AnimationStyle.duration] is provided, it will be used to override
+  /// the modal bottom sheet animation duration in the underlying
+  /// [BottomSheet.createAnimationController].
+  ///
+  /// If [AnimationStyle.reverseDuration] is provided, it will be used to
+  /// override the modal bottom sheet reverse animation duration in the
+  /// underlying [BottomSheet.createAnimationController].
+  ///
+  /// To disable the modal bottom sheet animation, use [AnimationStyle.noAnimation].
+  final AnimationStyle? sheetAnimationStyle;
+
   /// {@template flutter.material.ModalBottomSheetRoute.barrierOnTapHint}
   /// The semantic hint text that informs users what will happen if they
   /// tap on the widget. Announced in the format of 'Double tap to ...'.
@@ -1051,7 +1069,10 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
       _animationController = transitionAnimationController;
       willDisposeAnimationController = false;
     } else {
-      _animationController = BottomSheet.createAnimationController(navigator!);
+      _animationController = BottomSheet.createAnimationController(
+        navigator!,
+        sheetAnimationStyle: sheetAnimationStyle,
+      );
     }
     return _animationController!;
   }
@@ -1159,6 +1180,26 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
 /// ** See code in examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.1.dart **
 /// {@end-tool}
 ///
+/// The [sheetAnimationStyle] parameter is used to override the modal bottom sheet
+/// animation duration and reverse animation duration.
+///
+/// If [AnimationStyle.duration] is provided, it will be used to override
+/// the modal bottom sheet animation duration in the underlying
+/// [BottomSheet.createAnimationController].
+///
+/// If [AnimationStyle.reverseDuration] is provided, it will be used to
+/// override the modal bottom sheet reverse animation duration in the
+/// underlying [BottomSheet.createAnimationController].
+///
+/// To disable the bottom sheet animation, use [AnimationStyle.noAnimation].
+///
+/// {@tool dartpad}
+/// This sample showcases how to override the [showModalBottomSheet] animation
+/// duration and reverse animation duration using [AnimationStyle].
+///
+/// ** See code in examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.2.dart **
+/// {@end-tool}
+///
 /// See also:
 ///
 ///  * [BottomSheet], which becomes the parent of the widget returned by the
@@ -1171,6 +1212,8 @@ class ModalBottomSheetRoute<T> extends PopupRoute<T> {
 ///    [DisplayFeature]s can split the screen into sub-screens.
 ///  * The Material 2 spec at <https://m2.material.io/components/sheets-bottom>.
 ///  * The Material 3 spec at <https://m3.material.io/components/bottom-sheets/overview>.
+///  * [AnimationStyle], which is used to override the modal bottom sheet
+///    animation duration and reverse animation duration.
 Future<T?> showModalBottomSheet<T>({
   required BuildContext context,
   required WidgetBuilder builder,
@@ -1191,6 +1234,7 @@ Future<T?> showModalBottomSheet<T>({
   RouteSettings? routeSettings,
   AnimationController? transitionAnimationController,
   Offset? anchorPoint,
+  AnimationStyle? sheetAnimationStyle,
 }) {
   assert(debugCheckHasMediaQuery(context));
   assert(debugCheckHasMaterialLocalizations(context));
@@ -1217,6 +1261,7 @@ Future<T?> showModalBottomSheet<T>({
     transitionAnimationController: transitionAnimationController,
     anchorPoint: anchorPoint,
     useSafeArea: useSafeArea,
+    sheetAnimationStyle: sheetAnimationStyle,
   ));
 }
 
@@ -1235,6 +1280,26 @@ Future<T?> showModalBottomSheet<T>({
 /// The [enableDrag] parameter specifies whether the bottom sheet can be
 /// dragged up and down and dismissed by swiping downwards.
 ///
+/// The [sheetAnimationStyle] parameter is used to override the bottom sheet
+/// animation duration and reverse animation duration.
+///
+/// If [AnimationStyle.duration] is provided, it will be used to override
+/// the bottom sheet animation duration in the underlying
+/// [BottomSheet.createAnimationController].
+///
+/// If [AnimationStyle.reverseDuration] is provided, it will be used to
+/// override the bottom sheet reverse animation duration in the underlying
+/// [BottomSheet.createAnimationController].
+///
+/// To disable the bottom sheet animation, use [AnimationStyle.noAnimation].
+///
+/// {@tool dartpad}
+/// This sample showcases how to override the [showBottomSheet] animation
+/// duration and reverse animation duration using [AnimationStyle].
+///
+/// ** See code in examples/api/lib/material/bottom_sheet/show_bottom_sheet.0.dart **
+/// {@end-tool}
+///
 /// To rebuild the bottom sheet (e.g. if it is stateful), call
 /// [PersistentBottomSheetController.setState] on the controller returned by
 /// this method.
@@ -1265,6 +1330,8 @@ Future<T?> showModalBottomSheet<T>({
 ///  * [Scaffold.of], for information about how to obtain the [BuildContext].
 ///  * The Material 2 spec at <https://m2.material.io/components/sheets-bottom>.
 ///  * The Material 3 spec at <https://m3.material.io/components/bottom-sheets/overview>.
+///  * [AnimationStyle], which is used to override the bottom sheet animation
+///    duration and reverse animation duration.
 PersistentBottomSheetController showBottomSheet({
   required BuildContext context,
   required WidgetBuilder builder,
@@ -1276,6 +1343,7 @@ PersistentBottomSheetController showBottomSheet({
   bool? enableDrag,
   bool? showDragHandle,
   AnimationController? transitionAnimationController,
+  AnimationStyle? sheetAnimationStyle,
 }) {
   assert(debugCheckHasScaffold(context));
 
@@ -1289,6 +1357,7 @@ PersistentBottomSheetController showBottomSheet({
     enableDrag: enableDrag,
     showDragHandle: showDragHandle,
     transitionAnimationController: transitionAnimationController,
+    sheetAnimationStyle: sheetAnimationStyle,
   );
 }
 

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

@@ -2506,6 +2506,26 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
   ///
   /// ** See code in examples/api/lib/material/scaffold/scaffold_state.show_bottom_sheet.0.dart **
   /// {@end-tool}
+  ///
+  /// The [sheetAnimationStyle] parameter is used to override the bottom sheet
+  /// animation duration and reverse animation duration.
+  ///
+  /// If [AnimationStyle.duration] is provided, it will be used to override
+  /// the bottom sheet animation duration in the underlying
+  /// [BottomSheet.createAnimationController].
+  ///
+  /// If [AnimationStyle.reverseDuration] is provided, it will be used to
+  /// override the bottom sheet reverse animation duration in the underlying
+  /// [BottomSheet.createAnimationController].
+  ///
+  /// To disable the bottom sheet animation, use [AnimationStyle.noAnimation].
+  ///
+  /// {@tool dartpad}
+  /// This sample showcases how to override the [showBottomSheet] animation
+  /// duration and reverse animation duration using [AnimationStyle].
+  ///
+  /// ** See code in examples/api/lib/material/scaffold/scaffold_state.show_bottom_sheet.1.dart **
+  /// {@end-tool}
   /// See also:
   ///
   ///  * [BottomSheet], which becomes the parent of the widget returned by the
@@ -2516,6 +2536,8 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
   ///  * [Scaffold.of], for information about how to obtain the [ScaffoldState].
   ///  * The Material 2 spec at <https://m2.material.io/components/sheets-bottom>.
   ///  * The Material 3 spec at <https://m3.material.io/components/bottom-sheets/overview>.
+  ///  * [AnimationStyle], which is used to override the modal bottom sheet
+  ///    animation duration and reverse animation duration.
   PersistentBottomSheetController showBottomSheet(
     WidgetBuilder builder, {
     Color? backgroundColor,
@@ -2526,6 +2548,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
     bool? enableDrag,
     bool? showDragHandle,
     AnimationController? transitionAnimationController,
+    AnimationStyle? sheetAnimationStyle,
   }) {
     assert(() {
       if (widget.bottomSheet != null) {
@@ -2540,7 +2563,9 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
     assert(debugCheckHasMediaQuery(context));
 
     _closeCurrentBottomSheet();
-    final AnimationController controller = (transitionAnimationController ?? BottomSheet.createAnimationController(this))..forward();
+    final AnimationController controller = (transitionAnimationController
+      ?? BottomSheet.createAnimationController(this, sheetAnimationStyle: sheetAnimationStyle))
+         ..forward();
     setState(() {
       _currentBottomSheet = _buildBottomSheet(
         builder,

packages/flutter/test/material/bottom_sheet_test.dart

@@ -2290,6 +2290,252 @@ void main() {
       expect(modalBarrier.semanticsLabel, MaterialLocalizations.of(scaffoldKey.currentContext!).scrimLabel);
     });
   });
+
+  testWidgets('Bottom sheet animation can be customized', (WidgetTester tester) async {
+    final Key sheetKey = UniqueKey();
+
+    Widget buildWidget({ AnimationStyle? sheetAnimationStyle }) {
+      return MaterialApp(
+        home: Scaffold(
+          body: Builder(
+            builder: (BuildContext context) {
+              return GestureDetector(
+                onTap: () {
+                  showBottomSheet(
+                    context: context,
+                    sheetAnimationStyle: sheetAnimationStyle,
+                    builder: (BuildContext context) {
+                      return SizedBox.expand(
+                        child: ColoredBox(
+                          key: sheetKey,
+                          color: Theme.of(context).colorScheme.primary,
+                          child: FilledButton(
+                            onPressed: () {
+                              Navigator.pop(context);
+                            },
+                            child: const Text('Close'),
+                          ),
+                        ),
+                      );
+                    },
+                  );
+                },
+                child: const Text('X'),
+              );
+            },
+          ),
+        ),
+      );
+    }
+
+    // Test custom animation style.
+    await tester.pumpWidget(buildWidget(
+      sheetAnimationStyle: AnimationStyle(
+        duration: const Duration(milliseconds: 800),
+        reverseDuration: const Duration(milliseconds: 400),
+      ),
+    ));
+    await tester.tap(find.text('X'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(0.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is dismissed.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(600.0));
+
+    // Test no animation style.
+    await tester.pumpWidget(buildWidget(sheetAnimationStyle: AnimationStyle.noAnimation));
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('X'));
+    await tester.pump();
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(0.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+
+    // The bottom sheet is dismissed.
+    expect(find.byKey(sheetKey), findsNothing);
+  });
+
+  testWidgets('Modal bottom sheet default animation', (WidgetTester tester) async {
+    final Key sheetKey = UniqueKey();
+
+    // Test default modal bottom sheet animation.
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: Builder(
+          builder: (BuildContext context) {
+            return GestureDetector(
+              onTap: () {
+                showModalBottomSheet<void>(
+                  context: context,
+                  builder: (BuildContext context) {
+                    return SizedBox.expand(
+                      child: ColoredBox(
+                        key: sheetKey,
+                        color: Theme.of(context).colorScheme.primary,
+                        child: FilledButton(
+                          onPressed: () {
+                            Navigator.pop(context);
+                          },
+                          child: const Text('Close'),
+                        ),
+                      ),
+                    );
+                  },
+                );
+              },
+              child: const Text('X'),
+            );
+          },
+        ),
+      ),
+    ));
+
+    // Tap the 'X' to show the bottom sheet.
+    await tester.tap(find.text('X'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The modal bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The modal bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(262.5));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default reverse duration.
+    await tester.pump(const Duration(milliseconds: 100));
+
+    // The modal bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the default reverse duration.
+    await tester.pump(const Duration(milliseconds: 100));
+
+    // The modal bottom sheet is dismissed.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(600.0));
+  });
+
+  testWidgets('Modal bottom sheet animation can be customized', (WidgetTester tester) async {
+    final Key sheetKey = UniqueKey();
+
+    Widget buildWidget({ AnimationStyle? sheetAnimationStyle }) {
+      return MaterialApp(
+        home: Scaffold(
+          body: Builder(
+            builder: (BuildContext context) {
+              return GestureDetector(
+                onTap: () {
+                  showModalBottomSheet<void>(
+                    context: context,
+                    sheetAnimationStyle: sheetAnimationStyle,
+                    builder: (BuildContext context) {
+                      return SizedBox.expand(
+                        child: ColoredBox(
+                          key: sheetKey,
+                          color: Theme.of(context).colorScheme.primary,
+                          child: FilledButton(
+                            onPressed: () {
+                              Navigator.pop(context);
+                            },
+                            child: const Text('Close'),
+                          ),
+                        ),
+                      );
+                    },
+                  );
+                },
+                child: const Text('X'),
+              );
+            },
+          ),
+        ),
+      );
+    }
+
+    // Test custom animation style.
+    await tester.pumpWidget(buildWidget(
+      sheetAnimationStyle: AnimationStyle(
+        duration: const Duration(milliseconds: 800),
+        reverseDuration: const Duration(milliseconds: 400),
+      ),
+    ));
+    await tester.tap(find.text('X'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(262.5));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(316.7, 0.1));
+
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is dismissed.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(600.0));
+
+    // Test no animation style.
+    await tester.pumpWidget(buildWidget(sheetAnimationStyle: AnimationStyle.noAnimation));
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('X'));
+    await tester.pump();
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(262.5));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+
+    // The bottom sheet is dismissed.
+    expect(find.byKey(sheetKey), findsNothing);
+  });
 }
 
 class _TestPage extends StatelessWidget {

packages/flutter/test/material/scaffold_test.dart

@@ -3102,6 +3102,160 @@ void main() {
       // The SnackBar is dismissed.
       expect(tester.getTopLeft(find.text('I am a snack bar.')).dy, closeTo(614, 0.1));
   });
+
+  testWidgets('Scaffold showBottomSheet default animation', (WidgetTester tester) async {
+    final Key sheetKey = UniqueKey();
+
+    // Test default bottom sheet animation.
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: Builder(
+          builder: (BuildContext context) {
+            return GestureDetector(
+              onTap: () {
+                Scaffold.of(context).showBottomSheet(
+                  (BuildContext context) {
+                    return SizedBox.expand(
+                      child: ColoredBox(
+                        key: sheetKey,
+                        color: Theme.of(context).colorScheme.primary,
+                        child: FilledButton(
+                          onPressed: () {
+                            Navigator.pop(context);
+                          },
+                          child: const Text('Close'),
+                        ),
+                      ),
+                    );
+                  },
+                );
+              },
+              child: const Text('X'),
+            );
+          },
+        ),
+      ),
+    ));
+
+    // Tap the 'X' to show the bottom sheet.
+    await tester.tap(find.text('X'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the default forward duration.
+    await tester.pump(const Duration(milliseconds: 125));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(0.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the default reverse duration.
+    await tester.pump(const Duration(milliseconds: 100));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the default reverse duration.
+    await tester.pump(const Duration(milliseconds: 100));
+
+    // The bottom sheet is dismissed.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(600.0));
+  });
+
+  testWidgets('Scaffold showBottomSheet animation can be customized', (WidgetTester tester) async {
+    final Key sheetKey = UniqueKey();
+
+    Widget buildWidget({ AnimationStyle? sheetAnimationStyle }) {
+      return MaterialApp(
+        home: Scaffold(
+          body: Builder(
+            builder: (BuildContext context) {
+              return GestureDetector(
+                onTap: () {
+                  Scaffold.of(context).showBottomSheet(
+                    sheetAnimationStyle: sheetAnimationStyle,
+                    (BuildContext context) {
+                      return SizedBox.expand(
+                        child: ColoredBox(
+                          key: sheetKey,
+                          color: Theme.of(context).colorScheme.primary,
+                          child: FilledButton(
+                            onPressed: () {
+                              Navigator.pop(context);
+                            },
+                            child: const Text('Close'),
+                          ),
+                        ),
+                      );
+                    },
+                  );
+                },
+                child: const Text('X'),
+              );
+            },
+          ),
+        ),
+      );
+    }
+
+    // Test custom animation style.
+    await tester.pumpWidget(buildWidget(
+      sheetAnimationStyle: AnimationStyle(
+        duration: const Duration(milliseconds: 800),
+        reverseDuration: const Duration(milliseconds: 400),
+      ),
+    ));
+    await tester.tap(find.text('X'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the custom forward duration.
+    await tester.pump(const Duration(milliseconds: 400));
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(0.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is partially visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, closeTo(134.6, 0.1));
+
+    // Advance the animation by 1/2 of the custom reverse duration.
+    await tester.pump(const Duration(milliseconds: 200));
+
+    // The bottom sheet is dismissed.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(600.0));
+
+    // Test no animation style.
+    await tester.pumpWidget(buildWidget(sheetAnimationStyle: AnimationStyle.noAnimation));
+    await tester.pumpAndSettle();
+    await tester.tap(find.text('X'));
+    await tester.pump();
+
+    // The bottom sheet is fully visible.
+    expect(tester.getTopLeft(find.byKey(sheetKey)).dy, equals(0.0));
+
+    // Dismiss the bottom sheet.
+    await tester.tap(find.widgetWithText(FilledButton, 'Close'));
+    await tester.pump();
+
+    // The bottom sheet is dismissed.
+    expect(find.byKey(sheetKey), findsNothing);
+  });
 }
 
 class _GeometryListener extends StatefulWidget {