Fix Checkbox default visual density to meet Material 3 guidelines (#159081)

Fixes [Compact Visual Density is wrongfully applied to Checkboxes with `MaterialTapTargetSize.padded` on desktop platforms according to Material 3 Guidelines](https://github.com/flutter/flutter/issues/156408) ### Description This PR updates default `Checkbox` visual density to not depend on `ThemeData.visualDenSity` as it will return `VisualDensity.compact` on desktop and break Material 3 guidelines for `Checkbox`. > [!NOTE] > This makes a similar fix as https://github.com/flutter/flutter/pull/110722. ### Code sample <details> <summary>expand to view the code sample</summary> ```dart 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( debugShowCheckedModeBanner: false, home: Scaffold( body: Center( child: Row( mainAxisAlignment: MainAxisAlignment.center, children: [ ColoredBox( color: Colors.amber, child: Checkbox( materialTapTargetSize: MaterialTapTargetSize.padded, value: true, onChanged: (bool? value) {}, ), ), Container( width: 48, height: 48, color: Colors.red, alignment: Alignment.center, child: const Text( '48x48px', style: TextStyle(fontSize: 10, color: Colors.white), ), ) ], ), ), ), ); } } ``` </details> <img width="577" alt="Screenshot 2024-11-18 at 18 02 01" src="https://github.com/user-attachments/assets/d390c92f-dd62-4c42-b6b7-d4f101078618"> <img width="577" alt="Screenshot 2024-11-18 at 18 01 49" src="https://github.com/user-attachments/assets/632e8d19-11bf-45c7-9be9-5c4fc308f3ea"> ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord].  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
2025-01-30 22:03:56 +02:00 · 2025-01-30 22:03:56 +02:00 · 9d7d36cfba
commit 9d7d36cfba
parent a4927668cb
4 changed files with 76 additions and 13 deletions
--- a/dev/tools/gen_defaults/lib/checkbox_template.dart
+++ b/dev/tools/gen_defaults/lib/checkbox_template.dart
@ -134,7 +134,7 @@ class _${blockName}DefaultsM3 extends CheckboxThemeData {
  MaterialTapTargetSize get materialTapTargetSize => _theme.materialTapTargetSize;

  @override
-  VisualDensity get visualDensity => _theme.visualDensity;
+  VisualDensity get visualDensity => VisualDensity.standard;

  @override
  OutlinedBorder get shape => const RoundedRectangleBorder(
--- a/packages/flutter/lib/src/material/checkbox.dart
+++ b/packages/flutter/lib/src/material/checkbox.dart
@ -284,7 +284,9 @@ class Checkbox extends StatefulWidget {
  /// {@macro flutter.material.themedata.visualDensity}
  ///
  /// If null, then the value of [CheckboxThemeData.visualDensity] is used. If
-  /// that is also null, then the value of [ThemeData.visualDensity] is used.
+  /// that is also null and if [ThemeData.useMaterial3] is false, then the
+  /// value of [ThemeData.visualDensity] is used. Otherwise, the default value
+  /// is [VisualDensity.standard].
  ///
  /// See also:
  ///
@ -1041,7 +1043,7 @@ class _CheckboxDefaultsM3 extends CheckboxThemeData {
  MaterialTapTargetSize get materialTapTargetSize => _theme.materialTapTargetSize;

  @override
-  VisualDensity get visualDensity => _theme.visualDensity;
+  VisualDensity get visualDensity => VisualDensity.standard;

  @override
  OutlinedBorder get shape => const RoundedRectangleBorder(
--- a/packages/flutter/lib/src/material/theme_data.dart
+++ b/packages/flutter/lib/src/material/theme_data.dart
@ -1161,10 +1161,14 @@ class ThemeData with Diagnosticable {
  /// A larger value translates to a spacing increase (less dense), and a
  /// smaller value translates to a spacing decrease (more dense).
  ///
-  /// In Material Design 3, the [visualDensity] does not override the value of
-  /// [IconButton.visualDensity] which defaults to [VisualDensity.standard]
-  /// for all platforms. To override the default value of [IconButton.visualDensity],
-  /// use [ThemeData.iconButtonTheme] instead.
+  /// In Material Design 3, the [visualDensity] does not override the default
+  /// visual for the following components which are set to [VisualDensity.standard]
+  /// for all platforms:
+  ///
+  ///  * [IconButton] - To override the default value of [IconButton.visualDensity],
+  ///    use [ThemeData.iconButtonTheme] instead.
+  ///  * [Checkbox] - To override the default value of [Checkbox.visualDensity],
+  ///    use [ThemeData.checkboxTheme] instead.
  /// {@endtemplate}
  final VisualDensity visualDensity;

--- a/packages/flutter/test/material/checkbox_test.dart
+++ b/packages/flutter/test/material/checkbox_test.dart
@ -1057,9 +1057,57 @@ void main() {
    expect(value, isTrue);
  });

-  testWidgets('Checkbox responds to density changes.', (WidgetTester tester) async {
+  testWidgets(
+    'Material3 - Checkbox visual density cannot be overriden by ThemeData.visualDensity',
+    (WidgetTester tester) async {
+      const Key key = Key('test');
+      Widget buldCheckbox() {
+        return MaterialApp(
+          theme: theme.copyWith(visualDensity: VisualDensity.compact),
+          home: Material(
+            child: Center(child: Checkbox(key: key, value: true, onChanged: (bool? value) {})),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(buldCheckbox());
+      await tester.pumpAndSettle();
+      final RenderBox box = tester.renderObject(find.byKey(key));
+      expect(box.size, equals(const Size(48, 48)));
+    },
+  );
+
+  testWidgets(
+    'Material3 - Checkbox with MaterialTapTargetSize.padded meets Material Guidelines on desktop',
+    (WidgetTester tester) async {
+      const Key key = Key('test');
+      Widget buldCheckbox() {
+        return MaterialApp(
+          theme: theme,
+          home: Material(
+            child: Center(
+              child: Checkbox(
+                key: key,
+                materialTapTargetSize: MaterialTapTargetSize.padded,
+                value: true,
+                onChanged: (bool? value) {},
+              ),
+            ),
+          ),
+        );
+      }
+
+      await tester.pumpWidget(buldCheckbox());
+      await tester.pumpAndSettle();
+      final RenderBox box = tester.renderObject(find.byKey(key));
+      expect(box.size, equals(const Size(48, 48)));
+    },
+    variant: TargetPlatformVariant.desktop(),
+  );
+
+  testWidgets('Checkbox responds to density changes', (WidgetTester tester) async {
    const Key key = Key('test');
-    Future<void> buildTest(VisualDensity visualDensity) async {
+    Future<void> buildTest({VisualDensity? visualDensity}) async {
      return tester.pumpWidget(
        MaterialApp(
          theme: theme,
@ -1077,20 +1125,29 @@ void main() {
      );
    }

-    await buildTest(VisualDensity.standard);
+    // Test the default visual density.
+    await buildTest();
+    await tester.pumpAndSettle();
    final RenderBox box = tester.renderObject(find.byKey(key));
+    expect(box.size, equals(const Size(48, 48)));
+
+    await buildTest(visualDensity: VisualDensity.standard);
    await tester.pumpAndSettle();
    expect(box.size, equals(const Size(48, 48)));

-    await buildTest(const VisualDensity(horizontal: 3.0, vertical: 3.0));
+    await buildTest(visualDensity: VisualDensity.compact);
+    await tester.pumpAndSettle();
+    expect(box.size, equals(const Size(40, 40)));
+
+    await buildTest(visualDensity: const VisualDensity(horizontal: 3.0, vertical: 3.0));
    await tester.pumpAndSettle();
    expect(box.size, equals(const Size(60, 60)));

-    await buildTest(const VisualDensity(horizontal: -3.0, vertical: -3.0));
+    await buildTest(visualDensity: const VisualDensity(horizontal: -3.0, vertical: -3.0));
    await tester.pumpAndSettle();
    expect(box.size, equals(const Size(36, 36)));

-    await buildTest(const VisualDensity(horizontal: 3.0, vertical: -3.0));
+    await buildTest(visualDensity: const VisualDensity(horizontal: 3.0, vertical: -3.0));
    await tester.pumpAndSettle();
    expect(box.size, equals(const Size(60, 36)));
  });