Support Material 3 in bottom sheet

dev/tools/gen_defaults/bin/gen_defaults.dart

@@ -20,6 +20,7 @@ import 'dart:io';
 import 'package:gen_defaults/action_chip_template.dart';
 import 'package:gen_defaults/app_bar_template.dart';
 import 'package:gen_defaults/banner_template.dart';
+import 'package:gen_defaults/bottom_sheet_template.dart';
 import 'package:gen_defaults/button_template.dart';
 import 'package:gen_defaults/card_template.dart';
 import 'package:gen_defaults/checkbox_template.dart';
@@ -88,6 +89,7 @@ Future<void> main(List<String> args) async {
     'radio_button.json',
     'segmented_button_outlined.json',
     'shape.json',
+    'sheet_bottom.json',
     'slider.json',
     'state.json',
     'switch.json',
@@ -115,6 +117,7 @@ Future<void> main(List<String> args) async {
   ActionChipTemplate('ActionChip', '$materialLib/action_chip.dart', tokens).updateFile();
   AppBarTemplate('AppBar', '$materialLib/app_bar.dart', tokens).updateFile();
   BannerTemplate('Banner', '$materialLib/banner.dart', tokens).updateFile();
+  BottomSheetTemplate('BottomSheet', '$materialLib/bottom_sheet.dart', tokens).updateFile();
   ButtonTemplate('md.comp.elevated-button', 'ElevatedButton', '$materialLib/elevated_button.dart', tokens).updateFile();
   ButtonTemplate('md.comp.filled-button', 'FilledButton', '$materialLib/filled_button.dart', tokens).updateFile();
   ButtonTemplate('md.comp.filled-tonal-button', 'FilledTonalButton', '$materialLib/filled_button.dart', tokens).updateFile();

dev/tools/gen_defaults/lib/bottom_sheet_template.dart

@@ -0,0 +1,30 @@
+// 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 'template.dart';
+
+class BottomSheetTemplate extends TokenTemplate {
+  const BottomSheetTemplate(super.blockName, super.fileName, super.tokens);
+
+  @override
+  String generate() => '''
+// Generated version ${tokens["version"]}
+class _${blockName}DefaultsM3 extends BottomSheetThemeData {
+   const _${blockName}DefaultsM3(this.context)
+    : super(
+      elevation: ${elevation("md.comp.sheet.bottom.docked.standard.container")},
+      modalElevation: ${elevation("md.comp.sheet.bottom.docked.modal.container")},
+      shape: ${shape("md.comp.sheet.bottom.docked.container")},
+    );
+
+  final BuildContext context;
+
+  @override
+  Color? get backgroundColor => ${componentColor("md.comp.sheet.bottom.docked.container")};
+
+  @override
+  Color? get surfaceTintColor => ${componentColor("md.comp.sheet.bottom.docked.container.surface-tint-layer")};
+}
+''';
+}

dev/tools/gen_defaults/lib/template.dart

@@ -177,6 +177,12 @@ abstract class TokenTemplate {
         if (topLeft == topRight && topLeft == bottomLeft && topLeft == bottomRight) {
           return '${prefix}RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular($topLeft)))';
         }
+        if (topLeft == topRight && bottomLeft == bottomRight) {
+          return '${prefix}RoundedRectangleBorder(borderRadius: BorderRadius.vertical('
+          '${topLeft > 0 ? 'top: Radius.circular($topLeft),':''}'
+          '${bottomLeft > 0 ? 'bottom: Radius.circular($bottomLeft),':''}'
+          '))';
+        }
         return '${prefix}RoundedRectangleBorder(borderRadius: '
             'BorderRadius.only('
             'topLeft: Radius.circular(${shape['topLeft']}), '

examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.1.dart

@@ -0,0 +1,61 @@
+// 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.
+
+// Flutter code sample for  Material Design 3 TextFields.
+/// Flutter code sample for [showModalBottomSheet].
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      theme: ThemeData(colorSchemeSeed: const Color(0xff6750a4), useMaterial3: true),
+      home: Scaffold(
+        appBar: AppBar(title: const Text('Bottom Sheet Sample')),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: ElevatedButton(
+        child: const Text('showModalBottomSheet'),
+        onPressed: () {
+          showModalBottomSheet<void>(
+            context: context,
+            builder: (BuildContext context) {
+              return SizedBox(
+                height: 200,
+                child: Center(
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    mainAxisSize: MainAxisSize.min,
+                    children: <Widget>[
+                      const Text('Modal BottomSheet'),
+                      ElevatedButton(
+                        child: const Text('Close BottomSheet'),
+                        onPressed: () => Navigator.pop(context),
+                      ),
+                    ],
+                  ),
+                ),
+              );
+            },
+          );
+        },
+      ),
+    );
+  }
+}

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

@@ -274,16 +274,19 @@ class _BottomSheetState extends State<BottomSheet> {
   @override
   Widget build(BuildContext context) {
     final BottomSheetThemeData bottomSheetTheme = Theme.of(context).bottomSheetTheme;
+    final BottomSheetThemeData defaults = Theme.of(context).useMaterial3 ? _BottomSheetDefaultsM3(context) : const BottomSheetThemeData();
     final BoxConstraints? constraints = widget.constraints ?? bottomSheetTheme.constraints;
-    final Color? color = widget.backgroundColor ?? bottomSheetTheme.backgroundColor;
-    final double elevation = widget.elevation ?? bottomSheetTheme.elevation ?? 0;
-    final ShapeBorder? shape = widget.shape ?? bottomSheetTheme.shape;
+    final Color? color = widget.backgroundColor ?? bottomSheetTheme.backgroundColor ?? defaults.backgroundColor;
+    final Color? surfaceTintColor = bottomSheetTheme.surfaceTintColor ?? defaults.surfaceTintColor;
+    final double elevation = widget.elevation ?? bottomSheetTheme.elevation ?? defaults.elevation ?? 0;
+    final ShapeBorder? shape = widget.shape ?? bottomSheetTheme.shape ?? defaults.shape;
     final Clip clipBehavior = widget.clipBehavior ?? bottomSheetTheme.clipBehavior ?? Clip.none;
 
     Widget bottomSheet = Material(
       key: _childKey,
       color: color,
       elevation: elevation,
+      surfaceTintColor: surfaceTintColor,
       shape: shape,
       clipBehavior: clipBehavior,
       child: NotificationListener<DraggableScrollableNotification>(
@@ -526,10 +529,11 @@ class _ModalBottomSheetRoute<T> extends PopupRoute<T> {
       child: Builder(
         builder: (BuildContext context) {
           final BottomSheetThemeData sheetTheme = Theme.of(context).bottomSheetTheme;
+          final BottomSheetThemeData defaults = Theme.of(context).useMaterial3 ? _BottomSheetDefaultsM3(context) : const BottomSheetThemeData();
           return _ModalBottomSheet<T>(
             route: this,
-            backgroundColor: backgroundColor ?? sheetTheme.modalBackgroundColor ?? sheetTheme.backgroundColor,
-            elevation: elevation ?? sheetTheme.modalElevation ?? sheetTheme.elevation,
+            backgroundColor: backgroundColor ?? sheetTheme.modalBackgroundColor ?? sheetTheme.backgroundColor ?? defaults.backgroundColor,
+            elevation: elevation ?? sheetTheme.modalElevation ?? defaults.modalElevation ?? sheetTheme.elevation,
             shape: shape,
             clipBehavior: clipBehavior,
             constraints: constraints,
@@ -727,7 +731,7 @@ Future<T?> showModalBottomSheet<T>({
     clipBehavior: clipBehavior,
     constraints: constraints,
     isDismissible: isDismissible,
-    modalBarrierColor: barrierColor,
+    modalBarrierColor: barrierColor ?? Theme.of(context).bottomSheetTheme.modalBarrierColor,
     enableDrag: enableDrag,
     settings: routeSettings,
     transitionAnimationController: transitionAnimationController,
@@ -806,3 +810,34 @@ PersistentBottomSheetController<T> showBottomSheet<T>({
     transitionAnimationController: transitionAnimationController,
   );
 }
+
+
+
+// BEGIN GENERATED TOKEN PROPERTIES - BottomSheet
+
+// Do not edit by hand. The code between the "BEGIN GENERATED" and
+// "END GENERATED" comments are generated from data in the Material
+// Design token database by the script:
+//   dev/tools/gen_defaults/bin/gen_defaults.dart.
+
+// Token database version: v0_132
+
+// Generated version v0_132
+class _BottomSheetDefaultsM3 extends BottomSheetThemeData {
+   const _BottomSheetDefaultsM3(this.context)
+    : super(
+      elevation: 1.0,
+      modalElevation: 1.0,
+      shape: const RoundedRectangleBorder(borderRadius: BorderRadius.vertical(top: Radius.circular(28.0))),
+    );
+
+  final BuildContext context;
+
+  @override
+  Color? get backgroundColor => Theme.of(context).colorScheme.surface;
+
+  @override
+  Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
+}
+
+// END GENERATED TOKEN PROPERTIES - BottomSheet

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

@@ -29,8 +29,10 @@ class BottomSheetThemeData with Diagnosticable {
   /// Creates a theme that can be used for [ThemeData.bottomSheetTheme].
   const BottomSheetThemeData({
     this.backgroundColor,
+    this.surfaceTintColor,
     this.elevation,
     this.modalBackgroundColor,
+    this.modalBarrierColor,
     this.modalElevation,
     this.shape,
     this.clipBehavior,
@@ -42,6 +44,13 @@ class BottomSheetThemeData with Diagnosticable {
   /// If null, [BottomSheet] defaults to [Material]'s default.
   final Color? backgroundColor;
 
+  /// Default value for surfaceTintColor.
+  ///
+  /// If null, [BottomSheet] will not display an overlay color.
+  ///
+  /// See [Material.surfaceTintColor] for more details.
+  final Color? surfaceTintColor;
+
   /// Default value for [BottomSheet.elevation].
   ///
   /// {@macro flutter.material.material.elevation}
@@ -53,6 +62,10 @@ class BottomSheetThemeData with Diagnosticable {
   /// as a modal bottom sheet.
   final Color? modalBackgroundColor;
 
+  /// Default value for barrier color when the Bottom sheet is presented as
+  /// a modal bottom sheet.
+  final Color? modalBarrierColor;
+
   /// Value for [BottomSheet.elevation] when the Bottom sheet is presented as a
   /// modal bottom sheet.
   final double? modalElevation;
@@ -77,17 +90,21 @@ class BottomSheetThemeData with Diagnosticable {
   /// new values.
   BottomSheetThemeData copyWith({
     Color? backgroundColor,
+    Color? surfaceTintColor,
     double? elevation,
     Color? modalBackgroundColor,
+    Color? modalBarrierColor,
     double? modalElevation,
     ShapeBorder? shape,
     Clip? clipBehavior,
     BoxConstraints? constraints,
   }) {
     return BottomSheetThemeData(
       backgroundColor: backgroundColor ?? this.backgroundColor,
+      surfaceTintColor: surfaceTintColor ?? this.surfaceTintColor,
       elevation: elevation ?? this.elevation,
       modalBackgroundColor: modalBackgroundColor ?? this.modalBackgroundColor,
+      modalBarrierColor: modalBarrierColor ?? this.modalBarrierColor,
       modalElevation: modalElevation ?? this.modalElevation,
       shape: shape ?? this.shape,
       clipBehavior: clipBehavior ?? this.clipBehavior,
@@ -107,8 +124,10 @@ class BottomSheetThemeData with Diagnosticable {
     }
     return BottomSheetThemeData(
       backgroundColor: Color.lerp(a?.backgroundColor, b?.backgroundColor, t),
+      surfaceTintColor: Color.lerp(a?.surfaceTintColor, b?.surfaceTintColor, t),
       elevation: lerpDouble(a?.elevation, b?.elevation, t),
       modalBackgroundColor: Color.lerp(a?.modalBackgroundColor, b?.modalBackgroundColor, t),
+      modalBarrierColor: Color.lerp(a?.modalBarrierColor, b?.modalBarrierColor, t),
       modalElevation: lerpDouble(a?.modalElevation, b?.modalElevation, t),
       shape: ShapeBorder.lerp(a?.shape, b?.shape, t),
       clipBehavior: t < 0.5 ? a?.clipBehavior : b?.clipBehavior,
@@ -119,8 +138,10 @@ class BottomSheetThemeData with Diagnosticable {
   @override
   int get hashCode => Object.hash(
     backgroundColor,
+    surfaceTintColor,
     elevation,
     modalBackgroundColor,
+    modalBarrierColor,
     modalElevation,
     shape,
     clipBehavior,
@@ -137,8 +158,10 @@ class BottomSheetThemeData with Diagnosticable {
     }
     return other is BottomSheetThemeData
         && other.backgroundColor == backgroundColor
+        && other.surfaceTintColor == surfaceTintColor
         && other.elevation == elevation
         && other.modalBackgroundColor == modalBackgroundColor
+        && other.modalBarrierColor == modalBarrierColor
         && other.modalElevation == modalElevation
         && other.shape == shape
         && other.clipBehavior == clipBehavior
@@ -149,8 +172,10 @@ class BottomSheetThemeData with Diagnosticable {
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
     properties.add(ColorProperty('backgroundColor', backgroundColor, defaultValue: null));
+    properties.add(ColorProperty('surfaceTintColor', surfaceTintColor, defaultValue: null));
     properties.add(DoubleProperty('elevation', elevation, defaultValue: null));
     properties.add(ColorProperty('modalBackgroundColor', modalBackgroundColor, defaultValue: null));
+    properties.add(ColorProperty('modalBarrierColor', modalBarrierColor, defaultValue: null));
     properties.add(DoubleProperty('modalElevation', modalElevation, defaultValue: null));
     properties.add(DiagnosticsProperty<ShapeBorder>('shape', shape, defaultValue: null));
     properties.add(DiagnosticsProperty<Clip>('clipBehavior', clipBehavior, defaultValue: null));

packages/flutter/test/material/bottom_sheet_test.dart

@@ -833,6 +833,45 @@ void main() {
     expect(modalBarrier.color, barrierColor);
   });
 
+  testWidgets('BottomSheet uses fallback values in maretial3',
+      (WidgetTester tester) async {
+    const Color surfaceColor = Colors.pink;
+    const Color surfaceTintColor = Colors.blue;
+    const ShapeBorder defaultShape = RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(
+      top: Radius.circular(28.0),
+    ));
+
+    await tester.pumpWidget(MaterialApp(
+      theme: ThemeData(
+        colorScheme: const ColorScheme.light(
+          surface: surfaceColor,
+          surfaceTint: surfaceTintColor,
+        ),
+        useMaterial3: true,
+      ),
+      home: Scaffold(
+        body: BottomSheet(
+          onClosing: () {},
+          builder: (BuildContext context) {
+            return Container();
+          },
+        ),
+      ),
+    ));
+
+    final Material material = tester.widget<Material>(
+      find.descendant(
+        of: find.byType(BottomSheet),
+        matching: find.byType(Material),
+      ),
+    );
+    expect(material.color, surfaceColor);
+    expect(material.surfaceTintColor, surfaceTintColor);
+    expect(material.elevation, 1.0);
+    expect(material.shape, defaultShape);
+  });
+
   testWidgets('modal BottomSheet with scrollController has semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
     final GlobalKey<ScaffoldState> scaffoldKey = GlobalKey<ScaffoldState>();

packages/flutter/test/material/bottom_sheet_theme_test.dart

@@ -148,12 +148,14 @@ void main() {
     const double modalElevation = 5.0;
     const double persistentElevation = 7.0;
     const Color modalBackgroundColor = Colors.yellow;
+    const Color modalBarrierColor = Colors.blue;
     const Color persistentBackgroundColor = Colors.red;
     const BottomSheetThemeData bottomSheetTheme = BottomSheetThemeData(
       elevation: persistentElevation,
       modalElevation: modalElevation,
       backgroundColor: persistentBackgroundColor,
       modalBackgroundColor: modalBackgroundColor,
+      modalBarrierColor:modalBarrierColor,
     );
 
     await tester.pumpWidget(bottomSheetWithElevations(bottomSheetTheme));
@@ -168,6 +170,9 @@ void main() {
     );
     expect(material.elevation, modalElevation);
     expect(material.color, modalBackgroundColor);
+
+    final ModalBarrier modalBarrier = tester.widget(find.byType(ModalBarrier).last);
+    expect(modalBarrier.color, modalBarrierColor);
   });
 
   testWidgets('General bottom sheet parameters take priority over modal bottom sheet-specific parameters for persistent bottom sheets', (WidgetTester tester) async {