[a11y] Add expanded flag support to Android. (#174981)

ksokolovskyi · ash2moon · web-flow · commit c6ffbdf7ea8d · 2025-09-27T00:13:18.000Z
Closes flutter/flutter#92040 - Adds `expanded` semantics flag support to Android - Adds `onExpand` and `onCollapse` semantics actions - Updates `robolectric` library - Adds java and dart tests #### Why were `onExpand` and `onCollapse` actions added? It turned out that TalkBack doesn't announce the `expanded` state if `expand/collapse` action is not set for the accessibility node. #### Why was the `robolectric` library updated? The `expanded` state support in Android was introduced in API 36. The `roboelectric: 4.14.1` doesn't support API 36. To run tests for a newly added functionality `roboelectric` library was updated to `4.16`, which supports the latest Android version (https://github.com/robolectric/robolectric/releases/tag/robolectric-4.16). In case you think it would be better to update the `roboelectric` in a separate PR, please let me know. <br/> <details> <summary>Example Source Code</summary> ```dart import 'package:flutter/material.dart'; void main() { runApp(const App()); } class App extends StatefulWidget { const App({super.key}); @OverRide State<App> createState() => _AppState(); } class _AppState extends State<App> { final _controller = ExpansibleController(); @OverRide void dispose() { _controller.dispose(); super.dispose(); } @OverRide Widget build(BuildContext context) { return MaterialApp( debugShowCheckedModeBanner: false, home: Scaffold( body: Column( mainAxisAlignment: MainAxisAlignment.center, spacing: 24, children: [ Text('Expansible Example'), ListenableBuilder( listenable: _controller, builder: (context, child) { return Semantics( expanded: _controller.isExpanded, onExpand: () { print(' \n onExpand \n '); _controller.expand(); }, onCollapse: () { print(' \n onCollapse \n '); _controller.collapse(); }, child: child, ); }, child: Expansible( headerBuilder: (context, _) => ListTile( tileColor: Colors.blue.shade100, leading: Text( 'Expansible', style: TextStyle(fontSize: 20), ), trailing: Icon( _controller.isExpanded ? Icons.arrow_upward : Icons.arrow_downward, semanticLabel: _controller.isExpanded ? 'Arrow Up icon' : 'Arrow Down icon', ), ), bodyBuilder: (context, _) { return Container( color: Colors.blue, height: 200, width: 200, ); }, controller: _controller, ), ), ], ), ), ); } } ``` </details> https://github.com/user-attachments/assets/256c4182-a1e3-44fc-b028-5e6c9ec05ad7 ## 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]. - [X] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [X] All existing and new tests are passing.  [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 --------- Co-authored-by: ash2moon <muhatashim@google.com>
diff --git a/engine/src/flutter/lib/ui/semantics.dart b/engine/src/flutter/lib/ui/semantics.dart
@@ -46,6 +46,8 @@ class SemanticsAction {
   static const int _kSetTextIndex = 1 << 21;
   static const int _kFocusIndex = 1 << 22;
   static const int _kScrollToOffsetIndex = 1 << 23;
+  static const int _kExpandIndex = 1 << 24;
+  static const int _kCollapseIndex = 1 << 25;
   // READ THIS:
   // - The maximum supported bit index on the web (in JS mode) is 1 << 31.
   // - If you add an action here, you MUST update the numSemanticsActions value
@@ -298,6 +300,16 @@ class SemanticsAction {
   ///      VoiceOver (iOS), moving which does not move the input focus.
   static const SemanticsAction focus = SemanticsAction._(_kFocusIndex, 'focus');
 
+  /// A request that the node should be expanded.
+  ///
+  /// For example, this action might be recognized by a dropdown.
+  static const SemanticsAction expand = SemanticsAction._(_kExpandIndex, 'expand');
+
+  /// A request that the node should be collapsed.
+  ///
+  /// For example, this action might be recognized by a dropdown.
+  static const SemanticsAction collapse = SemanticsAction._(_kCollapseIndex, 'collapse');
+
   /// The possible semantics actions.
   ///
   /// The map's key is the [index] of the action and the value is the action
@@ -327,6 +339,8 @@ class SemanticsAction {
     _kMoveCursorBackwardByWordIndex: moveCursorBackwardByWord,
     _kSetTextIndex: setText,
     _kFocusIndex: focus,
+    _kExpandIndex: expand,
+    _kCollapseIndex: collapse,
   };
 
   // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
diff --git a/engine/src/flutter/lib/ui/semantics/semantics_node.h b/engine/src/flutter/lib/ui/semantics/semantics_node.h
@@ -45,6 +45,8 @@ enum class SemanticsAction : int32_t {
   kSetText = 1 << 21,
   kFocus = 1 << 22,
   kScrollToOffset = 1 << 23,
+  kExpand = 1 << 24,
+  kCollapse = 1 << 25,
 };
 
 constexpr int kVerticalScrollSemanticsActions =
diff --git a/engine/src/flutter/lib/web_ui/lib/semantics.dart b/engine/src/flutter/lib/web_ui/lib/semantics.dart
@@ -34,6 +34,8 @@ class SemanticsAction {
   static const int _kSetTextIndex = 1 << 21;
   static const int _kFocusIndex = 1 << 22;
   static const int _kScrollToOffsetIndex = 1 << 23;
+  static const int _kExpandIndex = 1 << 24;
+  static const int _kCollapseIndex = 1 << 25;
 
   static const SemanticsAction tap = SemanticsAction._(_kTapIndex, 'tap');
   static const SemanticsAction longPress = SemanticsAction._(_kLongPressIndex, 'longPress');
@@ -89,6 +91,8 @@ class SemanticsAction {
     'moveCursorBackwardByWord',
   );
   static const SemanticsAction focus = SemanticsAction._(_kFocusIndex, 'focus');
+  static const SemanticsAction expand = SemanticsAction._(_kExpandIndex, 'expand');
+  static const SemanticsAction collapse = SemanticsAction._(_kCollapseIndex, 'collapse');
 
   static const Map<int, SemanticsAction> _kActionById = <int, SemanticsAction>{
     _kTapIndex: tap,
@@ -115,6 +119,8 @@ class SemanticsAction {
     _kMoveCursorBackwardByWordIndex: moveCursorBackwardByWord,
     _kSetTextIndex: setText,
     _kFocusIndex: focus,
+    _kExpandIndex: expand,
+    _kCollapseIndex: collapse,
   };
 
   static List<SemanticsAction> get values => _kActionById.values.toList(growable: false);
diff --git a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_api_test.dart b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_api_test.dart
@@ -29,7 +29,7 @@ void testMain() {
   });
 
   // This must match the number of actions in lib/ui/semantics.dart
-  const int numSemanticsActions = 24;
+  const int numSemanticsActions = 26;
   test('SemanticsAction.values refers to all actions.', () async {
     expect(SemanticsAction.values.length, equals(numSemanticsActions));
     for (int index = 0; index < numSemanticsActions; ++index) {
diff --git a/engine/src/flutter/shell/platform/android/build.gradle b/engine/src/flutter/shell/platform/android/build.gradle
@@ -55,7 +55,7 @@ android {
         implementation "androidx.test:core:1.4.0"
         implementation "com.google.android.play:core:1.8.0"
         implementation "com.ibm.icu:icu4j:69.1"
-        implementation "org.robolectric:robolectric:4.14.1"
+        implementation "org.robolectric:robolectric:4.16"
         implementation "junit:junit:4.13.2"
         implementation "androidx.test.ext:junit:1.1.4-alpha07"
 
diff --git a/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/engine/src/flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java
@@ -1015,6 +1015,22 @@ public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) {
     }
     result.setSelected(semanticsNode.hasFlag(Flag.IS_SELECTED));
 
+    if (Build.VERSION.SDK_INT >= API_LEVELS.API_36) {
+      if (semanticsNode.hasFlag(Flag.HAS_EXPANDED_STATE)) {
+        final boolean isExpanded = semanticsNode.hasFlag(Flag.IS_EXPANDED);
+        result.setExpandedState(
+            isExpanded
+                ? AccessibilityNodeInfo.EXPANDED_STATE_FULL
+                : AccessibilityNodeInfo.EXPANDED_STATE_COLLAPSED);
+        if (semanticsNode.hasAction(Action.EXPAND)) {
+          result.addAction(AccessibilityNodeInfo.ACTION_EXPAND);
+        }
+        if (semanticsNode.hasAction(Action.COLLAPSE)) {
+          result.addAction(AccessibilityNodeInfo.ACTION_COLLAPSE);
+        }
+      }
+    }
+
     // Heading support
     if (Build.VERSION.SDK_INT >= API_LEVELS.API_28) {
       result.setHeading(semanticsNode.hasFlag(Flag.IS_HEADER));
@@ -1292,6 +1308,16 @@ public boolean performAction(
         {
           return performSetText(semanticsNode, virtualViewId, arguments);
         }
+      case AccessibilityNodeInfo.ACTION_EXPAND:
+        {
+          accessibilityChannel.dispatchSemanticsAction(virtualViewId, Action.EXPAND);
+          return true;
+        }
+      case AccessibilityNodeInfo.ACTION_COLLAPSE:
+        {
+          accessibilityChannel.dispatchSemanticsAction(virtualViewId, Action.COLLAPSE);
+          return true;
+        }
       default:
         // might be a custom accessibility accessibilityAction.
         final int flutterId = accessibilityAction - FIRST_RESOURCE_ID;
@@ -2168,7 +2194,9 @@ public enum Action {
     MOVE_CURSOR_BACKWARD_BY_WORD(1 << 20),
     SET_TEXT(1 << 21),
     FOCUS(1 << 22),
-    SCROLL_TO_OFFSET(1 << 23);
+    SCROLL_TO_OFFSET(1 << 23),
+    EXPAND(1 << 24),
+    COLLAPSE(1 << 25);
 
     public final int value;
 
diff --git a/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java b/engine/src/flutter/shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java
@@ -2119,6 +2119,156 @@ public void itAddsClickActionToSliderNodeInfo() {
     assertTrue(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_CLICK));
   }
 
+  @Config(sdk = API_LEVELS.API_36)
+  @TargetApi(API_LEVELS.API_36)
+  @Test
+  public void itSetsExpandedStateBasedOnFlagsCorrectly() {
+    AccessibilityBridge accessibilityBridge = setUpBridge();
+
+    TestSemanticsNode node = new TestSemanticsNode();
+    TestSemanticsUpdate testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    assertEquals(nodeInfo.getExpandedState(), AccessibilityNodeInfo.EXPANDED_STATE_UNDEFINED);
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    assertEquals(nodeInfo.getExpandedState(), AccessibilityNodeInfo.EXPANDED_STATE_COLLAPSED);
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addFlag(AccessibilityBridge.Flag.IS_EXPANDED);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    assertEquals(nodeInfo.getExpandedState(), AccessibilityNodeInfo.EXPANDED_STATE_FULL);
+  }
+
+  @Config(sdk = API_LEVELS.API_36)
+  @TargetApi(API_LEVELS.API_36)
+  @Test
+  public void itAddsExpandActionBasedOnFlagsCorrectly() {
+    AccessibilityBridge accessibilityBridge = setUpBridge();
+
+    TestSemanticsNode node = new TestSemanticsNode();
+    TestSemanticsUpdate testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    List<AccessibilityNodeInfo.AccessibilityAction> actions = nodeInfo.getActionList();
+    assertFalse(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_EXPAND));
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    actions = nodeInfo.getActionList();
+    assertFalse(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_EXPAND));
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addAction(AccessibilityBridge.Action.EXPAND);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    actions = nodeInfo.getActionList();
+    assertTrue(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_EXPAND));
+  }
+
+  @Config(sdk = API_LEVELS.API_36)
+  @TargetApi(API_LEVELS.API_36)
+  @Test
+  public void itCanPerformExpand() {
+    AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(
+            /* rootAccessibilityView= */ null,
+            /* accessibilityChannel= */ mockChannel,
+            /* accessibilityManager= */ null,
+            /* contentResolver= */ null,
+            /* accessibilityViewEmbedder= */ null,
+            /* platformViewsAccessibilityDelegate= */ null);
+
+    TestSemanticsNode node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addAction(AccessibilityBridge.Action.EXPAND);
+    TestSemanticsUpdate testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    accessibilityBridge.performAction(0, AccessibilityNodeInfo.ACTION_EXPAND, null);
+    verify(mockChannel).dispatchSemanticsAction(0, AccessibilityBridge.Action.EXPAND);
+  }
+
+  @Config(sdk = API_LEVELS.API_36)
+  @TargetApi(API_LEVELS.API_36)
+  @Test
+  public void itAddsCollapseActionBasedOnFlagsCorrectly() {
+    AccessibilityBridge accessibilityBridge = setUpBridge();
+
+    TestSemanticsNode node = new TestSemanticsNode();
+    TestSemanticsUpdate testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    List<AccessibilityNodeInfo.AccessibilityAction> actions = nodeInfo.getActionList();
+    assertFalse(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_COLLAPSE));
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addFlag(AccessibilityBridge.Flag.IS_EXPANDED);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    actions = nodeInfo.getActionList();
+    assertFalse(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_COLLAPSE));
+
+    node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addFlag(AccessibilityBridge.Flag.IS_EXPANDED);
+    node.addAction(AccessibilityBridge.Action.COLLAPSE);
+    testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    actions = nodeInfo.getActionList();
+    assertTrue(actions.contains(AccessibilityNodeInfo.AccessibilityAction.ACTION_COLLAPSE));
+  }
+
+  @Config(sdk = API_LEVELS.API_36)
+  @TargetApi(API_LEVELS.API_36)
+  @Test
+  public void itCanPerformCollapse() {
+    AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(
+            /* rootAccessibilityView= */ null,
+            /* accessibilityChannel= */ mockChannel,
+            /* accessibilityManager= */ null,
+            /* contentResolver= */ null,
+            /* accessibilityViewEmbedder= */ null,
+            /* platformViewsAccessibilityDelegate= */ null);
+
+    TestSemanticsNode node = new TestSemanticsNode();
+    node.addFlag(AccessibilityBridge.Flag.HAS_EXPANDED_STATE);
+    node.addFlag(AccessibilityBridge.Flag.IS_EXPANDED);
+    node.addAction(AccessibilityBridge.Action.COLLAPSE);
+    TestSemanticsUpdate testSemanticsUpdate = node.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    accessibilityBridge.performAction(0, AccessibilityNodeInfo.ACTION_COLLAPSE, null);
+    verify(mockChannel).dispatchSemanticsAction(0, AccessibilityBridge.Action.COLLAPSE);
+  }
+
   AccessibilityBridge setUpBridge() {
     return setUpBridge(null, null, null, null, null, null);
   }
diff --git a/engine/src/flutter/shell/platform/embedder/embedder.h b/engine/src/flutter/shell/platform/embedder/embedder.h
@@ -169,6 +169,10 @@ typedef enum {
   /// Request that scrolls the current scrollable container to a given scroll
   /// offset.
   kFlutterSemanticsActionScrollToOffset = 1 << 23,
+  /// A request that the node should be expanded.
+  kFlutterSemanticsActionExpand = 1 << 24,
+  /// A request that the node should be collapsed.
+  kFlutterSemanticsActionCollapse = 1 << 25,
 } FlutterSemanticsAction;
 
 /// The set of properties that may be associated with a semantics node.
diff --git a/engine/src/flutter/shell/platform/fuchsia/flutter/accessibility_bridge.cc b/engine/src/flutter/shell/platform/fuchsia/flutter/accessibility_bridge.cc
@@ -179,6 +179,12 @@ std::string NodeActionsToString(const flutter::SemanticsNode& node) {
   if (node.HasAction(flutter::SemanticsAction::kFocus)) {
     output += "kFocus|";
   }
+  if (node.HasAction(flutter::SemanticsAction::kExpand)) {
+    output += "kExpand|";
+  }
+  if (node.HasAction(flutter::SemanticsAction::kCollapse)) {
+    output += "kCollapse|";
+  }
 
   return output;
 }
diff --git a/engine/src/flutter/shell/platform/linux/fl_accessible_node.cc b/engine/src/flutter/shell/platform/linux/fl_accessible_node.cc
@@ -37,6 +37,8 @@ static ActionData action_mapping[] = {
     {kFlutterSemanticsActionMoveCursorBackwardByWord,
      "MoveCursorBackwardByWord"},
     {kFlutterSemanticsActionFocus, "Focus"},
+    {kFlutterSemanticsActionExpand, "Expand"},
+    {kFlutterSemanticsActionCollapse, "Collapse"},
     {static_cast<FlutterSemanticsAction>(0), nullptr}};
 
 struct FlAccessibleNodePrivate {
diff --git a/engine/src/flutter/testing/dart/semantics_test.dart b/engine/src/flutter/testing/dart/semantics_test.dart
@@ -22,7 +22,7 @@ void main() {
   });
 
   // This must match the number of actions in lib/ui/semantics.dart
-  const int numSemanticsActions = 24;
+  const int numSemanticsActions = 26;
   test('SemanticsAction.values refers to all actions.', () async {
     expect(SemanticsAction.values.length, equals(numSemanticsActions));
     for (int index = 0; index < numSemanticsActions; ++index) {
diff --git a/packages/flutter/lib/src/rendering/custom_paint.dart b/packages/flutter/lib/src/rendering/custom_paint.dart
@@ -1105,6 +1105,12 @@ class RenderCustomPaint extends RenderProxyBox {
     if (properties.onDismiss != null) {
       config.onDismiss = properties.onDismiss;
     }
+    if (properties.onExpand != null) {
+      config.onExpand = properties.onExpand;
+    }
+    if (properties.onCollapse != null) {
+      config.onCollapse = properties.onCollapse;
+    }
 
     newChild.updateWith(
       config: config,
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
@@ -5005,6 +5005,12 @@ mixin SemanticsAnnotationsMixin on RenderObject {
     if (_properties.onFocus != null) {
       config.onFocus = _performFocus;
     }
+    if (_properties.onExpand != null) {
+      config.onExpand = _performExpand;
+    }
+    if (_properties.onCollapse != null) {
+      config.onCollapse = _performCollapse;
+    }
     if (_properties.customSemanticsActions != null) {
       config.customSemanticsActions = _properties.customSemanticsActions!;
     }
@@ -5093,6 +5099,14 @@ mixin SemanticsAnnotationsMixin on RenderObject {
   void _performFocus() {
     _properties.onFocus?.call();
   }
+
+  void _performExpand() {
+    _properties.onExpand?.call();
+  }
+
+  void _performCollapse() {
+    _properties.onCollapse?.call();
+  }
 }
 
 /// Properties of _RenderObjectSemantics that are imposed from parent.
diff --git a/packages/flutter/lib/src/semantics/semantics.dart b/packages/flutter/lib/src/semantics/semantics.dart
diff --git a/packages/flutter/lib/src/widgets/basic.dart b/packages/flutter/lib/src/widgets/basic.dart
diff --git a/packages/flutter/test/widgets/custom_painter_test.dart b/packages/flutter/test/widgets/custom_painter_test.dart
diff --git a/packages/flutter/test/widgets/semantics_checks_test.dart b/packages/flutter/test/widgets/semantics_checks_test.dart
diff --git a/packages/flutter/test/widgets/semantics_test.dart b/packages/flutter/test/widgets/semantics_test.dart
diff --git a/packages/flutter/test/widgets/sliversemantics_test.dart b/packages/flutter/test/widgets/sliversemantics_test.dart

Original file line number	Diff line number	Diff line change
`@@ -179,6 +179,12 @@ std::string NodeActionsToString(const flutter::SemanticsNode& node) {`
`179`	`179`	`if (node.HasAction(flutter::SemanticsAction::kFocus)) {`
`180`	`180`	`output += "kFocus\|";`
`181`	`181`	`}`
	`182`	`+ if (node.HasAction(flutter::SemanticsAction::kExpand)) {`
	`183`	`+ output += "kExpand\|";`
	`184`	`+ }`
	`185`	`+ if (node.HasAction(flutter::SemanticsAction::kCollapse)) {`
	`186`	`+ output += "kCollapse\|";`
	`187`	`+ }`
`182`	`188`
`183`	`189`	`return output;`
`184`	`190`	`}`