[material_ui] Add Material 3 Expressive IconButton

packages/material_ui/lib/material_3.dart

@@ -0,0 +1,8 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Flutter widgets implementing Material Design 3.
+library material_3;
+
+export 'material_ui.dart';

packages/material_ui/lib/material_3_expressive.dart

@@ -0,0 +1,9 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Flutter widgets implementing Material 3 Expressive.
+library material_3_expressive;
+
+export 'material_ui.dart' hide IconButton;
+export 'src/material_3_expressive/icon_button.dart';

packages/material_ui/lib/src/button_style.dart

@@ -1,4 +1,4 @@
-// Copyright 2014 The Flutter Authors. All rights reserved.
+// Copyright 2013 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -31,6 +31,38 @@ import 'theme_data.dart';
 // late BuildContext context;
 // typedef MyAppHome = Placeholder;
 
+/// Defines size variants for Material 3 Expressive button components.
+///
+/// Components interpret each size variant according to their own token set.
+enum ButtonSize {
+  /// Extra small button size.
+  xSmall,
+
+  /// Small button size. This is the default for icon buttons.
+  small,
+
+  /// Medium button size.
+  medium,
+
+  /// Large button size.
+  large,
+
+  /// Extra large button size.
+  xLarge,
+}
+
+/// Defines the width variants for Material 3 Expressive [IconButton].
+enum IconButtonWidth {
+  /// Uses the narrow leading and trailing space tokens.
+  narrow,
+
+  /// Uses the default leading and trailing space tokens.
+  standard,
+
+  /// Uses the wide leading and trailing space tokens.
+  wide,
+}
+
 /// The type for [ButtonStyle.backgroundBuilder] and [ButtonStyle.foregroundBuilder].
 ///
 /// The [states] parameter is the button's current pressed/hovered/etc state. The [child] is
@@ -187,6 +219,8 @@ class ButtonStyle with Diagnosticable {
     this.splashFactory,
     this.backgroundBuilder,
     this.foregroundBuilder,
+    this.size,
+    this.iconButtonWidth,
   });
 
   /// The style for a button's [Text] widget descendants.
@@ -423,6 +457,12 @@ class ButtonStyle with Diagnosticable {
   ///    configuring clipping.
   final ButtonLayerBuilder? foregroundBuilder;
 
+  /// The size variant for this button.
+  final ButtonSize? size;
+
+  /// The width variant for this icon button.
+  final IconButtonWidth? iconButtonWidth;
+
   /// Returns a copy of this ButtonStyle with the given fields replaced with
   /// the new values.
   ButtonStyle copyWith({
@@ -451,6 +491,8 @@ class ButtonStyle with Diagnosticable {
     InteractiveInkFeatureFactory? splashFactory,
     ButtonLayerBuilder? backgroundBuilder,
     ButtonLayerBuilder? foregroundBuilder,
+    ButtonSize? size,
+    IconButtonWidth? iconButtonWidth,
   }) {
     return ButtonStyle(
       textStyle: textStyle ?? this.textStyle,
@@ -478,6 +520,8 @@ class ButtonStyle with Diagnosticable {
       splashFactory: splashFactory ?? this.splashFactory,
       backgroundBuilder: backgroundBuilder ?? this.backgroundBuilder,
       foregroundBuilder: foregroundBuilder ?? this.foregroundBuilder,
+      size: size ?? this.size,
+      iconButtonWidth: iconButtonWidth ?? this.iconButtonWidth,
     );
   }
 
@@ -516,6 +560,8 @@ class ButtonStyle with Diagnosticable {
       splashFactory: splashFactory ?? style.splashFactory,
       backgroundBuilder: backgroundBuilder ?? style.backgroundBuilder,
       foregroundBuilder: foregroundBuilder ?? style.foregroundBuilder,
+      size: size ?? style.size,
+      iconButtonWidth: iconButtonWidth ?? style.iconButtonWidth,
     );
   }
 
@@ -547,6 +593,8 @@ class ButtonStyle with Diagnosticable {
       splashFactory,
       backgroundBuilder,
       foregroundBuilder,
+      size,
+      iconButtonWidth,
     ];
     return Object.hashAll(values);
   }
@@ -584,7 +632,9 @@ class ButtonStyle with Diagnosticable {
         other.alignment == alignment &&
         other.splashFactory == splashFactory &&
         other.backgroundBuilder == backgroundBuilder &&
-        other.foregroundBuilder == foregroundBuilder;
+        other.foregroundBuilder == foregroundBuilder &&
+        other.size == size &&
+        other.iconButtonWidth == iconButtonWidth;
   }
 
   @override
@@ -706,6 +756,10 @@ class ButtonStyle with Diagnosticable {
         defaultValue: null,
       ),
     );
+    properties.add(EnumProperty<ButtonSize>('size', size, defaultValue: null));
+    properties.add(
+      EnumProperty<IconButtonWidth>('iconButtonWidth', iconButtonWidth, defaultValue: null),
+    );
   }
 
   /// Linearly interpolate between two [ButtonStyle]s.
@@ -769,6 +823,8 @@ class ButtonStyle with Diagnosticable {
       splashFactory: t < 0.5 ? a?.splashFactory : b?.splashFactory,
       backgroundBuilder: t < 0.5 ? a?.backgroundBuilder : b?.backgroundBuilder,
       foregroundBuilder: t < 0.5 ? a?.foregroundBuilder : b?.foregroundBuilder,
+      size: t < 0.5 ? a?.size : b?.size,
+      iconButtonWidth: t < 0.5 ? a?.iconButtonWidth : b?.iconButtonWidth,
     );
   }
 }

packages/material_ui/lib/src/button_style_button.dart

@@ -1,4 +1,4 @@
-// Copyright 2014 The Flutter Authors. All rights reserved.
+// Copyright 2013 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -87,6 +87,7 @@ abstract class ButtonStyleButton extends StatefulWidget {
     required this.clipBehavior,
     this.statesController,
     this.isSemanticButton = true,
+    this.isSelected,
     @Deprecated(
       'Remove this parameter as it is now ignored. '
       'Use ButtonStyle.iconAlignment instead. '
@@ -163,6 +164,9 @@ abstract class ButtonStyleButton extends StatefulWidget {
   /// Defaults to true.
   final bool? isSemanticButton;
 
+  /// Whether the button is selected.
+  final bool? isSelected;
+
   /// {@macro flutter.material.ButtonStyle.iconAlignment}
   @Deprecated(
     'Remove this parameter as it is now ignored. '
@@ -334,6 +338,9 @@ class _ButtonStyleState extends State<ButtonStyleButton> with TickerProviderStat
       internalStatesController = MaterialStatesController();
     }
     statesController.update(WidgetState.disabled, !widget.enabled);
+    if (widget.isSelected != null) {
+      statesController.update(WidgetState.selected, widget.isSelected!);
+    }
     statesController.addListener(handleStatesControllerChange);
   }
 
@@ -361,6 +368,9 @@ class _ButtonStyleState extends State<ButtonStyleButton> with TickerProviderStat
         statesController.update(WidgetState.pressed, false);
       }
     }
+    if (widget.isSelected != oldWidget.isSelected) {
+      statesController.update(WidgetState.selected, widget.isSelected ?? false);
+    }
   }
 
   @override
@@ -592,6 +602,7 @@ class _ButtonStyleState extends State<ButtonStyleButton> with TickerProviderStat
       container: true,
       button: widget.isSemanticButton,
       enabled: widget.enabled,
+      selected: widget.isSelected,
       child: _InputPadding(
         minSize: minSize,
         child: ConstrainedBox(