Fixing elevation issues with Material 3

dev/tools/gen_defaults/lib/action_chip_template.dart

@@ -31,10 +31,10 @@ class _${blockName}DefaultsM3 extends ChipThemeData {
   Color? get backgroundColor => ${componentColor("$tokenGroup$variant.container")};
 
   @override
-  Color? get shadowColor => ${color("$tokenGroup.container.shadow-color")};
+  Color? get shadowColor => ${colorOrTransparent("$tokenGroup.container.shadow-color")};
 
   @override
-  @override Color? get surfaceTintColor => ${color("$tokenGroup.container.surface-tint-layer.color")};
+  Color? get surfaceTintColor => ${colorOrTransparent("$tokenGroup.container.surface-tint-layer.color")};
 
   @override
   Color? get selectedColor => ${componentColor("$tokenGroup$variant.selected.container")};

dev/tools/gen_defaults/lib/app_bar_template.dart

@@ -34,7 +34,10 @@ class _${blockName}DefaultsM3 extends AppBarTheme {
   Color? get foregroundColor => ${color('md.comp.top-app-bar.small.headline.color')};
 
   @override
-  Color? get surfaceTintColor => ${componentColor('md.comp.top-app-bar.small.container.surface-tint-layer')};
+  Color? get shadowColor => ${colorOrTransparent('md.comp.top-app-bar.small.container.shadow-color')};
+
+  @override
+  Color? get surfaceTintColor => ${colorOrTransparent('md.comp.top-app-bar.small.container.surface-tint-layer.color')};
 
   @override
   IconThemeData? get iconTheme => IconThemeData(

dev/tools/gen_defaults/lib/button_template.dart

@@ -24,7 +24,7 @@ class ButtonTemplate extends TokenTemplate {
     }
     return '''
 
-    ButtonStyleButton.allOrNull<Color>(Colors.transparent)''';
+    const MaterialStatePropertyAll<Color>(Colors.transparent)''';
   }
 
   String _elevation() {
@@ -49,7 +49,15 @@ class ButtonTemplate extends TokenTemplate {
     }
     return '''
 
-    ButtonStyleButton.allOrNull<double>(0.0)''';
+    const MaterialStatePropertyAll<double>(0.0)''';
+  }
+
+  String _elevationColor(String token) {
+    if (tokens.containsKey(token)) {
+      return 'MaterialStatePropertyAll<Color>(${color(token)})';
+    } else {
+      return 'const MaterialStatePropertyAll<Color>(Colors.transparent)';
+    }
   }
 
   @override
@@ -96,34 +104,30 @@ class _${blockName}DefaultsM3 extends ButtonStyle {
       return null;
     });
 
-${tokens.containsKey("$tokenGroup.container.shadow-color") ? '''
   @override
   MaterialStateProperty<Color>? get shadowColor =>
-    ButtonStyleButton.allOrNull<Color>(${color("$tokenGroup.container.shadow-color")});''' : '''
-  // No default shadow color'''}
+    ${_elevationColor("$tokenGroup.container.shadow-color")};
 
-${tokens.containsKey("$tokenGroup.container.surface-tint-layer.color") ? '''
   @override
   MaterialStateProperty<Color>? get surfaceTintColor =>
-    ButtonStyleButton.allOrNull<Color>(${color("$tokenGroup.container.surface-tint-layer.color")});''' : '''
-  // No default surface tint color'''}
+    ${_elevationColor("$tokenGroup.container.surface-tint-layer.color")};
 
   @override
   MaterialStateProperty<double>? get elevation =>${_elevation()};
 
   @override
   MaterialStateProperty<EdgeInsetsGeometry>? get padding =>
-    ButtonStyleButton.allOrNull<EdgeInsetsGeometry>(_scaledPadding(context));
+    MaterialStatePropertyAll<EdgeInsetsGeometry>(_scaledPadding(context));
 
   @override
   MaterialStateProperty<Size>? get minimumSize =>
-    ButtonStyleButton.allOrNull<Size>(const Size(64.0, ${tokens["$tokenGroup.container.height"]}));
+    const MaterialStatePropertyAll<Size>(Size(64.0, ${tokens["$tokenGroup.container.height"]}));
 
   // No default fixedSize
 
   @override
   MaterialStateProperty<Size>? get maximumSize =>
-    ButtonStyleButton.allOrNull<Size>(Size.infinite);
+    const MaterialStatePropertyAll<Size>(Size.infinite);
 
 ${tokens.containsKey("$tokenGroup.outline.color") ? '''
   @override
@@ -138,7 +142,7 @@ ${tokens.containsKey("$tokenGroup.outline.color") ? '''
 
   @override
   MaterialStateProperty<OutlinedBorder>? get shape =>
-    ButtonStyleButton.allOrNull<OutlinedBorder>(${shape("$tokenGroup.container")});
+    const MaterialStatePropertyAll<OutlinedBorder>(${shape("$tokenGroup.container", '')});
 
   @override
   MaterialStateProperty<MouseCursor?>? get mouseCursor =>

dev/tools/gen_defaults/lib/card_template.dart

@@ -25,10 +25,10 @@ class _${blockName}DefaultsM3 extends CardTheme {
   Color? get color => ${componentColor("md.comp.elevated-card.container")};
 
   @override
-  Color? get shadowColor => ${color("md.comp.elevated-card.container.shadow-color")};
+  Color? get shadowColor => ${colorOrTransparent("md.comp.elevated-card.container.shadow-color")};
 
   @override
-  Color? get surfaceTintColor => ${color("md.comp.elevated-card.container.surface-tint-layer.color")};
+  Color? get surfaceTintColor => ${colorOrTransparent("md.comp.elevated-card.container.surface-tint-layer.color")};
 }
 ''';
 }

dev/tools/gen_defaults/lib/dialog_template.dart

@@ -27,9 +27,14 @@ class _${blockName}DefaultsM3 extends DialogTheme {
   @override
   Color? get iconColor => _colors.secondary;
 
-  // TODO(darrenaustin): overlay should be handled by Material widget: https://github.com/flutter/flutter/issues/9160
   @override
-  Color? get backgroundColor => ElevationOverlay.colorWithOverlay(${componentColor("md.comp.dialog.container")}, _colors.primary, ${elevation("md.comp.dialog.container")});
+  Color? get backgroundColor => ${componentColor("md.comp.dialog.container")};
+
+  @override
+  Color? get shadowColor => ${colorOrTransparent("md.comp.dialog.container.shadow-color")};
+
+  @override
+  Color? get surfaceTintColor => ${colorOrTransparent("md.comp.dialog.container.surface-tint-layer.color")};
 
   @override
   TextStyle? get titleTextStyle => ${textStyle("md.comp.dialog.headline")};

dev/tools/gen_defaults/lib/filter_chip_template.dart

@@ -31,10 +31,10 @@ class _${blockName}DefaultsM3 extends ChipThemeData {
   Color? get backgroundColor => ${componentColor("$tokenGroup$variant.container")};
 
   @override
-  Color? get shadowColor => ${color("$tokenGroup.container.shadow-color")};
+  Color? get shadowColor => ${colorOrTransparent("$tokenGroup.container.shadow-color")};
 
   @override
-  @override Color? get surfaceTintColor => ${color("$tokenGroup.container.surface-tint-layer.color")};
+  Color? get surfaceTintColor => ${colorOrTransparent("$tokenGroup.container.surface-tint-layer.color")};
 
   @override
   Color? get selectedColor => isEnabled

dev/tools/gen_defaults/lib/icon_button_template.dart

@@ -9,6 +9,15 @@ class IconButtonTemplate extends TokenTemplate {
     super.colorSchemePrefix = '_colors.',
   });
 
+
+  String _elevationColor(String token) {
+    if (tokens.containsKey(token)) {
+      return 'MaterialStatePropertyAll<Color>(${color(token)})';
+    } else {
+      return 'const MaterialStatePropertyAll<Color>(Colors.transparent)';
+    }
+  }
+
   @override
   String generate() => '''
 class _${blockName}DefaultsM3 extends ButtonStyle {
@@ -26,7 +35,7 @@ class _${blockName}DefaultsM3 extends ButtonStyle {
 
   @override
   MaterialStateProperty<Color?>? get backgroundColor =>
-    ButtonStyleButton.allOrNull<Color>(Colors.transparent);
+    const MaterialStatePropertyAll<Color?>(Colors.transparent);
 
   @override
   MaterialStateProperty<Color?>? get foregroundColor =>
@@ -66,37 +75,41 @@ class _${blockName}DefaultsM3 extends ButtonStyle {
       return null;
     });
 
-  // No default shadow color
+  @override
+  MaterialStateProperty<double>? get elevation =>
+    const MaterialStatePropertyAll<double>(0.0);
 
-  // No default surface tint color
+  @override
+  MaterialStateProperty<Color>? get shadowColor =>
+    ${_elevationColor("md.comp.icon-button.container.shadow-color")};
 
   @override
-  MaterialStateProperty<double>? get elevation =>
-    ButtonStyleButton.allOrNull<double>(0.0);
+  MaterialStateProperty<Color>? get surfaceTintColor =>
+    ${_elevationColor("md.comp.icon-button.container.surface-tint-layer.color")};
 
   @override
   MaterialStateProperty<EdgeInsetsGeometry>? get padding =>
-    ButtonStyleButton.allOrNull<EdgeInsetsGeometry>(const EdgeInsets.all(8.0));
+    const MaterialStatePropertyAll<EdgeInsetsGeometry>(EdgeInsets.all(8.0));
 
   @override
   MaterialStateProperty<Size>? get minimumSize =>
-    ButtonStyleButton.allOrNull<Size>(const Size(${tokens["md.comp.icon-button.state-layer.size"]}, ${tokens["md.comp.icon-button.state-layer.size"]}));
+    const MaterialStatePropertyAll<Size>(Size(${tokens["md.comp.icon-button.state-layer.size"]}, ${tokens["md.comp.icon-button.state-layer.size"]}));
 
   // No default fixedSize
 
   @override
   MaterialStateProperty<Size>? get maximumSize =>
-    ButtonStyleButton.allOrNull<Size>(Size.infinite);
+    const MaterialStatePropertyAll<Size>(Size.infinite);
 
   @override
   MaterialStateProperty<double>? get iconSize =>
-    ButtonStyleButton.allOrNull<double>(${tokens["md.comp.icon-button.icon.size"]});
+    const MaterialStatePropertyAll<double>(${tokens["md.comp.icon-button.icon.size"]});
 
   // No default side
 
   @override
   MaterialStateProperty<OutlinedBorder>? get shape =>
-    ButtonStyleButton.allOrNull<OutlinedBorder>(${shape("md.comp.icon-button.state-layer")});
+    const MaterialStatePropertyAll<OutlinedBorder>(${shape("md.comp.icon-button.state-layer", "")});
 
   @override
   MaterialStateProperty<MouseCursor?>? get mouseCursor =>

dev/tools/gen_defaults/lib/input_chip_template.dart

@@ -30,10 +30,10 @@ class _${blockName}DefaultsM3 extends ChipThemeData {
   Color? get backgroundColor => ${componentColor("$tokenGroup$variant.container")};
 
   @override
-  Color? get shadowColor => ${color("$tokenGroup.container.shadow-color")};
+  Color? get shadowColor => ${colorOrTransparent("$tokenGroup.container.shadow-color")};
 
   @override
-  @override Color? get surfaceTintColor => ${color("$tokenGroup.container.surface-tint-layer.color")};
+  Color? get surfaceTintColor => ${colorOrTransparent("$tokenGroup.container.surface-tint-layer.color")};
 
   @override
   Color? get selectedColor => ${componentColor("$tokenGroup$variant.selected.container")};

dev/tools/gen_defaults/lib/navigation_bar_template.dart

@@ -26,7 +26,9 @@ class _${blockName}DefaultsM3 extends NavigationBarThemeData {
 
   @override Color? get backgroundColor => ${componentColor("md.comp.navigation-bar.container")};
 
-  @override Color? get surfaceTintColor => ${color("md.comp.navigation-bar.container.surface-tint-layer.color")};
+  @override Color? get shadowColor => ${colorOrTransparent("md.comp.navigation-bar.container.shadow-color")};
+
+  @override Color? get surfaceTintColor => ${colorOrTransparent("md.comp.navigation-bar.container.surface-tint-layer.color")};
 
   @override MaterialStateProperty<IconThemeData?>? get iconTheme {
     return MaterialStateProperty.resolveWith((Set<MaterialState> states) {

dev/tools/gen_defaults/lib/template.dart

@@ -97,16 +97,28 @@ abstract class TokenTemplate {
   /// If there is a value for the given token, this will return
   /// the value prepended with [colorSchemePrefix].
   ///
-  /// Otherwise it will return 'null'.
+  /// Otherwise it will return [defaultValue].
   ///
   /// See also:
   ///   * [componentColor], that provides support for an optional opacity.
-  String color(String colorToken) {
+  String color(String colorToken, [String defaultValue = 'null']) {
     return tokens.containsKey(colorToken)
       ? '$colorSchemePrefix${tokens[colorToken]}'
-      : 'null';
+      : defaultValue;
   }
 
+  /// Generate a [ColorScheme] color name for the given token or a transparent
+  /// color if there is no value for the token.
+  ///
+  /// If there is a value for the given token, this will return
+  /// the value prepended with [colorSchemePrefix].
+  ///
+  /// Otherwise it will return 'Colors.transparent'.
+  ///
+  /// See also:
+  ///   * [componentColor], that provides support for an optional opacity.
+  String? colorOrTransparent(String token) => color(token, 'Colors.transparent');
+
   /// Generate a [ColorScheme] color name for the given component's color
   /// with opacity if available.
   ///
@@ -154,18 +166,18 @@ abstract class TokenTemplate {
   /// Currently supports family:
   ///   - "SHAPE_FAMILY_ROUNDED_CORNERS" which maps to [RoundedRectangleBorder].
   ///   - "SHAPE_FAMILY_CIRCULAR" which maps to a [StadiumBorder].
-  String shape(String componentToken) {
+  String shape(String componentToken, [String prefix = 'const ']) {
     final Map<String, dynamic> shape = tokens[tokens['$componentToken.shape']!]! as Map<String, dynamic>;
     switch (shape['family']) {
       case 'SHAPE_FAMILY_ROUNDED_CORNERS':
-        return 'const RoundedRectangleBorder(borderRadius: '
+        return '${prefix}RoundedRectangleBorder(borderRadius: '
             'BorderRadius.only('
             'topLeft: Radius.circular(${shape['topLeft']}), '
             'topRight: Radius.circular(${shape['topRight']}), '
             'bottomLeft: Radius.circular(${shape['bottomLeft']}), '
             'bottomRight: Radius.circular(${shape['bottomRight']})))';
       case 'SHAPE_FAMILY_CIRCULAR':
-        return 'const StadiumBorder()';
+        return '${prefix}StadiumBorder()';
     }
     print('Unsupported shape family type: ${shape['family']} for $componentToken');
     return '';

examples/api/test/material/appbar/app_bar.1_test.dart

@@ -16,7 +16,7 @@ void main() {
 
     expect(find.widgetWithText(AppBar, 'AppBar Demo'), findsOneWidget);
     Material appbarMaterial = _getAppBarMaterial(tester);
-    expect(appbarMaterial.shadowColor, null);
+    expect(appbarMaterial.shadowColor, Colors.transparent);
     expect(appbarMaterial.elevation, 0);
 
     await tester.drag(find.text('Item 4'), _kOffset, touchSlopY: 0, warnIfMissed: false);

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

@@ -7,6 +7,7 @@ import 'package:flutter/widgets.dart';
 
 import 'chip.dart';
 import 'chip_theme.dart';
+import 'colors.dart';
 import 'debug.dart';
 import 'theme.dart';
 import 'theme_data.dart';
@@ -196,10 +197,10 @@ class _ActionChipDefaultsM3 extends ChipThemeData {
   Color? get backgroundColor => null;
 
   @override
-  Color? get shadowColor => null;
+  Color? get shadowColor => Colors.transparent;
 
   @override
-  @override Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
+  Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
 
   @override
   Color? get selectedColor => null;

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

@@ -12,6 +12,7 @@ import 'package:flutter/widgets.dart';
 import 'app_bar_theme.dart';
 import 'back_button.dart';
 import 'color_scheme.dart';
+import 'colors.dart';
 import 'constants.dart';
 import 'debug.dart';
 import 'flexible_space_bar.dart';
@@ -2370,6 +2371,9 @@ class _AppBarDefaultsM3 extends AppBarTheme {
   @override
   Color? get foregroundColor => _colors.onSurface;
 
+  @override
+  Color? get shadowColor => Colors.transparent;
+
   @override
   Color? get surfaceTintColor => _colors.surfaceTint;
 

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

@@ -213,7 +213,7 @@ class _FilterChipDefaultsM3 extends ChipThemeData {
   Color? get shadowColor => Theme.of(context).colorScheme.shadow;
 
   @override
-  @override Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
+  Color? get surfaceTintColor => Theme.of(context).colorScheme.surfaceTint;
 
   @override
   Color? get selectedColor => isEnabled