[material_ui] Add splashRadius property to BottomNavigationBar and BottomNavigationBarThemeData

packages/material_ui/lib/src/bottom_navigation_bar.dart

@@ -271,6 +271,7 @@ class BottomNavigationBar extends StatefulWidget {
     this.enableFeedback,
     this.landscapeLayout,
     this.useLegacyColorScheme = true,
+    this.splashRadius,
   }) : assert(items.length >= 2),
        assert(
          items.every((BottomNavigationBarItem item) => item.label != null),
@@ -285,6 +286,7 @@ class BottomNavigationBar extends StatefulWidget {
        ),
        assert(selectedFontSize >= 0.0),
        assert(unselectedFontSize >= 0.0),
+       assert(splashRadius == null || splashRadius > 0.0),
        selectedItemColor = selectedItemColor ?? fixedColor;
 
   /// Defines the appearance of the button items that are arrayed within the
@@ -463,6 +465,12 @@ class BottomNavigationBar extends StatefulWidget {
   /// To opt-in the new theming logic set the flag to `false`
   final bool useLegacyColorScheme;
 
+  /// The radius of the ink splash for [BottomNavigationBarItem] tap effects.
+  ///
+  /// If null, then the value of [BottomNavigationBarThemeData.splashRadius] is used.
+  /// If that is also null, the default splash radius of [InkResponse] is used.
+  final double? splashRadius;
+
   @override
   State<BottomNavigationBar> createState() => _BottomNavigationBarState();
 }
@@ -491,6 +499,7 @@ class _BottomNavigationTile extends StatelessWidget {
     required this.mouseCursor,
     required this.enableFeedback,
     required this.layout,
+    this.splashRadius,
   });
 
   final BottomNavigationBarType type;
@@ -512,6 +521,7 @@ class _BottomNavigationTile extends StatelessWidget {
   final MouseCursor mouseCursor;
   final bool enableFeedback;
   final BottomNavigationBarLandscapeLayout layout;
+  final double? splashRadius;
 
   @override
   Widget build(BuildContext context) {
@@ -593,6 +603,7 @@ class _BottomNavigationTile extends StatelessWidget {
       onTap: onTap,
       mouseCursor: mouseCursor,
       enableFeedback: enableFeedback,
+      radius: splashRadius,
       child: Padding(
         padding: EdgeInsets.only(top: topPadding, bottom: bottomPadding),
         child: _Tile(
@@ -1111,6 +1122,7 @@ class _BottomNavigationBarState extends State<BottomNavigationBar> with TickerPr
           indexLabel: localizations.tabLabel(tabIndex: i + 1, tabCount: widget.items.length),
           mouseCursor: effectiveMouseCursor,
           layout: layout,
+          splashRadius: widget.splashRadius ?? bottomTheme.splashRadius,
         ),
       );
     }

packages/material_ui/lib/src/bottom_navigation_bar_theme.dart

@@ -49,6 +49,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
     this.enableFeedback,
     this.landscapeLayout,
     this.mouseCursor,
+    this.splashRadius,
   });
 
   /// The color of the [BottomNavigationBar] itself.
@@ -131,6 +132,11 @@ class BottomNavigationBarThemeData with Diagnosticable {
   /// If specified, overrides the default value of [BottomNavigationBar.mouseCursor].
   final WidgetStateProperty<MouseCursor?>? mouseCursor;
 
+  /// If specified, defines the splash radius for [BottomNavigationBar] item tap effects.
+  ///
+  /// If [BottomNavigationBar.splashRadius] is provided, [splashRadius] is ignored.
+  final double? splashRadius;
+
   /// Creates a copy of this object but with the given fields replaced with the
   /// new values.
   BottomNavigationBarThemeData copyWith({
@@ -148,6 +154,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
     bool? enableFeedback,
     BottomNavigationBarLandscapeLayout? landscapeLayout,
     WidgetStateProperty<MouseCursor?>? mouseCursor,
+    double? splashRadius,
   }) {
     return BottomNavigationBarThemeData(
       backgroundColor: backgroundColor ?? this.backgroundColor,
@@ -164,6 +171,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
       enableFeedback: enableFeedback ?? this.enableFeedback,
       landscapeLayout: landscapeLayout ?? this.landscapeLayout,
       mouseCursor: mouseCursor ?? this.mouseCursor,
+      splashRadius: splashRadius ?? this.splashRadius,
     );
   }
 
@@ -193,6 +201,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
       enableFeedback: t < 0.5 ? a?.enableFeedback : b?.enableFeedback,
       landscapeLayout: t < 0.5 ? a?.landscapeLayout : b?.landscapeLayout,
       mouseCursor: t < 0.5 ? a?.mouseCursor : b?.mouseCursor,
+      splashRadius: lerpDouble(a?.splashRadius, b?.splashRadius, t),
     );
   }
 
@@ -212,6 +221,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
     enableFeedback,
     landscapeLayout,
     mouseCursor,
+    splashRadius,
   );
 
   @override
@@ -236,7 +246,8 @@ class BottomNavigationBarThemeData with Diagnosticable {
         other.type == type &&
         other.enableFeedback == enableFeedback &&
         other.landscapeLayout == landscapeLayout &&
-        other.mouseCursor == mouseCursor;
+        other.mouseCursor == mouseCursor &&
+        other.splashRadius == splashRadius;
   }
 
   @override
@@ -292,6 +303,7 @@ class BottomNavigationBarThemeData with Diagnosticable {
         defaultValue: null,
       ),
     );
+    properties.add(DoubleProperty('splashRadius', splashRadius, defaultValue: null));
   }
 }
 

packages/material_ui/pending_changelogs/change_2026_08_28_1787928881949.yaml

@@ -0,0 +1,3 @@
+changelog: |
+  - Adds splashRadius property to BottomNavigationBar and BottomNavigationBarThemeData.
+version: minor

packages/material_ui/test/bottom_navigation_bar_test.dart

@@ -3127,6 +3127,77 @@ void main() {
 
     expect(tester.getSemantics(find.text('B')), isSemantics(label: 'B\nTab 2 of 2'));
   });
+
+  testWidgets('BottomNavigationBar splashRadius defaults to null', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      boilerplate(
+        textDirection: TextDirection.ltr,
+        bottomNavigationBar: BottomNavigationBar(
+          items: const <BottomNavigationBarItem>[
+            BottomNavigationBarItem(icon: Icon(Icons.ac_unit), label: 'A'),
+            BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: 'B'),
+          ],
+        ),
+      ),
+    );
+
+    final Iterable<InkResponse> inkResponses = tester.widgetList<InkResponse>(
+      find.descendant(of: find.byType(BottomNavigationBar), matching: find.byType(InkResponse)),
+    );
+    expect(inkResponses.length, 2);
+    for (final inkResponse in inkResponses) {
+      expect(inkResponse.radius, isNull);
+    }
+  });
+
+  testWidgets('BottomNavigationBar splashRadius test', (WidgetTester tester) async {
+    const splashRadius = 20.0;
+    await tester.pumpWidget(
+      boilerplate(
+        textDirection: TextDirection.ltr,
+        bottomNavigationBar: BottomNavigationBar(
+          splashRadius: splashRadius,
+          items: const <BottomNavigationBarItem>[
+            BottomNavigationBarItem(icon: Icon(Icons.ac_unit), label: 'A'),
+            BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: 'B'),
+          ],
+        ),
+      ),
+    );
+
+    final Iterable<InkResponse> inkResponses = tester.widgetList<InkResponse>(
+      find.descendant(of: find.byType(BottomNavigationBar), matching: find.byType(InkResponse)),
+    );
+    expect(inkResponses.length, 2);
+    for (final inkResponse in inkResponses) {
+      expect(inkResponse.radius, splashRadius);
+    }
+  });
+
+  testWidgets('BottomNavigationBar assert when splashRadius is non-positive', (
+    WidgetTester tester,
+  ) async {
+    expect(
+      () => BottomNavigationBar(
+        splashRadius: 0.0,
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(icon: Icon(Icons.ac_unit), label: 'A'),
+          BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: 'B'),
+        ],
+      ),
+      throwsAssertionError,
+    );
+    expect(
+      () => BottomNavigationBar(
+        splashRadius: -1.0,
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(icon: Icon(Icons.ac_unit), label: 'A'),
+          BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: 'B'),
+        ],
+      ),
+      throwsAssertionError,
+    );
+  });
 }
 
 Widget boilerplate({

packages/material_ui/test/bottom_navigation_bar_theme_test.dart

@@ -37,6 +37,7 @@ void main() {
     expect(themeData.type, null);
     expect(themeData.landscapeLayout, null);
     expect(themeData.mouseCursor, null);
+    expect(themeData.splashRadius, null);
 
     const theme = BottomNavigationBarTheme(data: BottomNavigationBarThemeData(), child: SizedBox());
     expect(theme.data.backgroundColor, null);
@@ -50,8 +51,9 @@ void main() {
     expect(theme.data.showSelectedLabels, null);
     expect(theme.data.showUnselectedLabels, null);
     expect(theme.data.type, null);
-    expect(themeData.landscapeLayout, null);
-    expect(themeData.mouseCursor, null);
+    expect(theme.data.landscapeLayout, null);
+    expect(theme.data.mouseCursor, null);
+    expect(theme.data.splashRadius, null);
   });
 
   testWidgets('Default BottomNavigationBarThemeData debugFillProperties', (
@@ -85,6 +87,7 @@ void main() {
       showUnselectedLabels: true,
       type: BottomNavigationBarType.fixed,
       mouseCursor: WidgetStateMouseCursor.clickable,
+      splashRadius: 18.0,
     ).debugFillProperties(builder);
 
     final List<String> description = builder.properties
@@ -109,6 +112,7 @@ void main() {
     expect(description[9], 'showUnselectedLabels: true');
     expect(description[10], 'type: BottomNavigationBarType.fixed');
     expect(description[11], 'mouseCursor: WidgetStateMouseCursor(clickable)');
+    expect(description[12], 'splashRadius: 18.0');
   });
 
   testWidgets('BottomNavigationBar is themeable', (WidgetTester tester) async {
@@ -142,6 +146,7 @@ void main() {
               }
               return SystemMouseCursors.move;
             }),
+            splashRadius: 28.0,
           ),
         ),
         home: Scaffold(
@@ -196,6 +201,10 @@ void main() {
     expect(_material(tester).elevation, equals(elevation));
     expect(_material(tester).color, equals(backgroundColor));
 
+    for (final InkResponse inkResponse in tester.widgetList<InkResponse>(find.byType(InkResponse))) {
+      expect(inkResponse.radius, 28.0);
+    }
+
     final Offset selectedBarItem = tester.getCenter(findACTransform);
     final Offset unselectedBarItem = tester.getCenter(findAlarmTransform);
     final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
@@ -258,6 +267,7 @@ void main() {
             unselectedLabelStyle: themeUnselectedTextStyle,
             landscapeLayout: themeLandscapeLayout,
             mouseCursor: themeCursor,
+            splashRadius: 28.0,
           ),
         ),
         home: Scaffold(
@@ -275,6 +285,7 @@ void main() {
             unselectedLabelStyle: unselectedTextStyle,
             landscapeLayout: landscapeLayout,
             mouseCursor: cursor,
+            splashRadius: 32.0,
             items: const <BottomNavigationBarItem>[
               BottomNavigationBarItem(icon: Icon(Icons.ac_unit), label: 'AC'),
               BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: 'Alarm'),
@@ -323,6 +334,12 @@ void main() {
     expect(_material(tester).elevation, equals(elevation));
     expect(_material(tester).color, equals(backgroundColor));
 
+    for (final InkResponse inkResponse in tester.widgetList<InkResponse>(
+      findDescendantOfBottomNavigationBar(find.byType(InkResponse)),
+    )) {
+      expect(inkResponse.radius, 32.0);
+    }
+
     final Offset barItem = tester.getCenter(
       findDescendantOfBottomNavigationBar(
         find.ancestor(of: find.text('AC'), matching: find.byType(Transform)),