Handle a11y focus event on Ios and android (#41777)

framework change:flutter/flutter#126171
issue: flutter/flutter#94523

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

shell/platform/android/io/flutter/embedding/engine/systemchannels/AccessibilityChannel.java

@@ -2,7 +2,6 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
 import io.flutter.Log;
 import io.flutter.embedding.engine.FlutterJNI;
 import io.flutter.embedding.engine.dart.DartExecutor;
@@ -24,8 +23,7 @@ public class AccessibilityChannel {
   @NonNull public final FlutterJNI flutterJNI;
   @Nullable private AccessibilityMessageHandler handler;
 
-  @VisibleForTesting
-  final BasicMessageChannel.MessageHandler<Object> parsingMessageHandler =
+  public final BasicMessageChannel.MessageHandler<Object> parsingMessageHandler =
       new BasicMessageChannel.MessageHandler<Object>() {
         @Override
         public void onMessage(
@@ -67,6 +65,14 @@ public void onMessage(
                 }
                 break;
               }
+            case "focus":
+              {
+                Integer nodeId = (Integer) annotatedEvent.get("nodeId");
+                if (nodeId != null) {
+                  handler.onFocus(nodeId);
+                }
+                break;
+              }
             case "tooltip":
               {
                 String tooltipMessage = (String) data.get("message");
@@ -170,12 +176,15 @@ public interface AccessibilityMessageHandler extends FlutterJNI.AccessibilityDel
     /** The Dart application would like the given {@code message} to be announced. */
     void announce(@NonNull String message);
 
-    /** The user has tapped on the widget with the given {@code nodeId}. */
+    /** The user has tapped on the semantics node with the given {@code nodeId}. */
     void onTap(int nodeId);
 
-    /** The user has long pressed on the widget with the given {@code nodeId}. */
+    /** The user has long pressed on the semantics node with the given {@code nodeId}. */
     void onLongPress(int nodeId);
 
+    /** The framework has requested focus on the semantics node with the given {@code nodeId}. */
+    void onFocus(int nodeId);
+
     /** The user has opened a tooltip. */
     void onTooltip(@NonNull String message);
   }

shell/platform/android/io/flutter/view/AccessibilityBridge.java

@@ -309,6 +309,12 @@ public void onLongPress(int nodeId) {
           sendAccessibilityEvent(nodeId, AccessibilityEvent.TYPE_VIEW_LONG_CLICKED);
         }
 
+        /** The framework has requested focus on the given {@code nodeId}. */
+        @Override
+        public void onFocus(int nodeId) {
+          sendAccessibilityEvent(nodeId, AccessibilityEvent.TYPE_VIEW_FOCUSED);
+        }
+
         /** The user has opened a tooltip. */
         @Override
         public void onTooltip(@NonNull String message) {
@@ -1883,7 +1889,8 @@ private AccessibilityEvent createTextChangedEvent(int id, String oldValue, Strin
    * <p>The given {@code viewId} may either belong to {@link #rootAccessibilityView}, or any Flutter
    * {@link SemanticsNode}.
    */
-  private void sendAccessibilityEvent(int viewId, int eventType) {
+  @VisibleForTesting
+  public void sendAccessibilityEvent(int viewId, int eventType) {
     if (!accessibilityManager.isEnabled()) {
       return;
     }
@@ -1976,12 +1983,17 @@ private void sendWindowContentChangeEvent(int virtualViewId) {
    * invoked to create an {@link AccessibilityEvent} for the {@link #rootAccessibilityView}.
    */
   private AccessibilityEvent obtainAccessibilityEvent(int virtualViewId, int eventType) {
-    AccessibilityEvent event = AccessibilityEvent.obtain(eventType);
+    AccessibilityEvent event = obtainAccessibilityEvent(eventType);
     event.setPackageName(rootAccessibilityView.getContext().getPackageName());
     event.setSource(rootAccessibilityView, virtualViewId);
     return event;
   }
 
+  @VisibleForTesting
+  public AccessibilityEvent obtainAccessibilityEvent(int eventType) {
+    return AccessibilityEvent.obtain(eventType);
+  }
+
   /**
    * Reads the {@code layoutInDisplayCutoutMode} value from the window attribute and returns whether
    * a left cutout inset is required.

shell/platform/android/test/io/flutter/embedding/engine/systemchannels/AccessibilityChannelTest.java

@@ -7,6 +7,7 @@
 import io.flutter.embedding.engine.FlutterJNI;
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.plugin.common.BasicMessageChannel;
+import java.util.HashMap;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.junit.Test;
@@ -30,4 +31,19 @@ public void repliesWhenNoAccessibilityHandler() throws JSONException {
     accessibilityChannel.parsingMessageHandler.onMessage(arguments, reply);
     verify(reply).reply(null);
   }
+
+  @Test
+  public void handleFocus() throws JSONException {
+    AccessibilityChannel accessibilityChannel =
+        new AccessibilityChannel(mock(DartExecutor.class), mock(FlutterJNI.class));
+    HashMap<String, Object> arguments = new HashMap<>();
+    arguments.put("type", "focus");
+    arguments.put("nodeId", 123);
+    AccessibilityChannel.AccessibilityMessageHandler handler =
+        mock(AccessibilityChannel.AccessibilityMessageHandler.class);
+    accessibilityChannel.setAccessibilityMessageHandler(handler);
+    BasicMessageChannel.Reply reply = mock(BasicMessageChannel.Reply.class);
+    accessibilityChannel.parsingMessageHandler.onMessage(arguments, reply);
+    verify(handler).onFocus(123);
+  }
 }

shell/platform/android/test/io/flutter/view/AccessibilityBridgeTest.java

@@ -44,12 +44,16 @@
 import android.view.accessibility.AccessibilityNodeInfo;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
+import io.flutter.embedding.engine.FlutterJNI;
+import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
+import io.flutter.plugin.common.BasicMessageChannel;
 import io.flutter.plugin.platform.PlatformViewsAccessibilityDelegate;
 import io.flutter.view.AccessibilityBridge.Flag;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -1827,6 +1831,66 @@ public void releaseDropsChannelMessageHandler() {
     verify(mockChannel, never()).setAccessibilityFeatures(anyInt());
   }
 
+  @Test
+  public void sendFocusAccessibilityEvent() {
+    AccessibilityManager mockManager = mock(AccessibilityManager.class);
+    AccessibilityChannel accessibilityChannel =
+        new AccessibilityChannel(mock(DartExecutor.class), mock(FlutterJNI.class));
+
+    ContentResolver mockContentResolver = mock(ContentResolver.class);
+    View mockRootView = mock(View.class);
+    Context context = mock(Context.class);
+    when(mockRootView.getContext()).thenReturn(context);
+    when(context.getPackageName()).thenReturn("test");
+    ViewParent mockParent = mock(ViewParent.class);
+    when(mockRootView.getParent()).thenReturn(mockParent);
+    when(mockManager.isEnabled()).thenReturn(true);
+
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(mockRootView, accessibilityChannel, mockManager, null, null, null);
+
+    HashMap<String, Object> arguments = new HashMap<>();
+    arguments.put("type", "focus");
+    arguments.put("nodeId", 123);
+    BasicMessageChannel.Reply reply = mock(BasicMessageChannel.Reply.class);
+    accessibilityChannel.parsingMessageHandler.onMessage(arguments, reply);
+
+    // Check that focus event was sent.
+    ArgumentCaptor<AccessibilityEvent> eventCaptor =
+        ArgumentCaptor.forClass(AccessibilityEvent.class);
+    verify(mockParent).requestSendAccessibilityEvent(eq(mockRootView), eventCaptor.capture());
+    AccessibilityEvent event = eventCaptor.getAllValues().get(0);
+    assertEquals(event.getEventType(), AccessibilityEvent.TYPE_VIEW_FOCUSED);
+    assertEquals(event.getSource(), null);
+  }
+
+  @Test
+  public void SetSourceAndPackageNameForAccessibilityEvent() {
+    AccessibilityManager mockManager = mock(AccessibilityManager.class);
+    ContentResolver mockContentResolver = mock(ContentResolver.class);
+    View mockRootView = mock(View.class);
+    Context context = mock(Context.class);
+    when(mockRootView.getContext()).thenReturn(context);
+    when(context.getPackageName()).thenReturn("test");
+    when(mockManager.isEnabled()).thenReturn(true);
+    ViewParent mockParent = mock(ViewParent.class);
+    when(mockRootView.getParent()).thenReturn(mockParent);
+    AccessibilityEvent mockEvent = mock(AccessibilityEvent.class);
+
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(mockRootView, null, mockManager, null, null, null);
+
+    AccessibilityBridge spyAccessibilityBridge = spy(accessibilityBridge);
+
+    when(spyAccessibilityBridge.obtainAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED))
+        .thenReturn(mockEvent);
+
+    spyAccessibilityBridge.sendAccessibilityEvent(123, AccessibilityEvent.TYPE_VIEW_FOCUSED);
+
+    verify(mockEvent).setPackageName("test");
+    verify(mockEvent).setSource(eq(mockRootView), eq(123));
+  }
+
   AccessibilityBridge setUpBridge() {
     return setUpBridge(null, null, null, null, null, null);
   }

shell/platform/darwin/ios/framework/Source/accessibility_bridge.h

@@ -57,6 +57,7 @@ class AccessibilityBridge final : public AccessibilityBridgeIos {
 
   void UpdateSemantics(flutter::SemanticsNodeUpdates nodes,
                        const flutter::CustomAccessibilityActionUpdates& actions);
+  void HandleEvent(NSDictionary<NSString*, id>* annotatedEvent);
   void DispatchSemanticsAction(int32_t id, flutter::SemanticsAction action) override;
   void DispatchSemanticsAction(int32_t id,
                                flutter::SemanticsAction action,
@@ -88,7 +89,6 @@ class AccessibilityBridge final : public AccessibilityBridgeIos {
   SemanticsObject* FindFirstFocusable(SemanticsObject* parent);
   void VisitObjectsRecursivelyAndRemove(SemanticsObject* object,
                                         NSMutableArray<NSNumber*>* doomed_uids);
-  void HandleEvent(NSDictionary<NSString*, id>* annotatedEvent);
 
   FlutterViewController* view_controller_;
   PlatformViewIOS* platform_view_;

shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm

@@ -362,6 +362,10 @@ static bool DidFlagChange(const flutter::SemanticsNode& oldNode,
     NSString* message = annotatedEvent[@"data"][@"message"];
     ios_delegate_->PostAccessibilityNotification(UIAccessibilityAnnouncementNotification, message);
   }
+  if ([type isEqualToString:@"focus"]) {
+    SemanticsObject* node = objects_.get()[annotatedEvent[@"nodeId"]];
+    ios_delegate_->PostAccessibilityNotification(UIAccessibilityLayoutChangedNotification, node);
+  }
 }
 
 fml::WeakPtr<AccessibilityBridge> AccessibilityBridge::GetWeakPtr() {

shell/platform/darwin/ios/framework/Source/accessibility_bridge_test.mm

@@ -1289,6 +1289,50 @@ - (void)testAnnouncesRouteChangesRemoveRouteInMiddle {
                  UIAccessibilityScreenChangedNotification);
 }
 
+- (void)testHandleEvent {
+  flutter::MockDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("AccessibilityBridgeTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*platform_views_controller=*/nil,
+      /*task_runners=*/runners,
+      /*worker_task_runner=*/nil,
+      /*is_gpu_disabled_sync_switch=*/nil);
+  id mockFlutterView = OCMClassMock([FlutterView class]);
+  id mockFlutterViewController = OCMClassMock([FlutterViewController class]);
+  OCMStub([mockFlutterViewController view]).andReturn(mockFlutterView);
+
+  NSMutableArray<NSDictionary<NSString*, id>*>* accessibility_notifications =
+      [[[NSMutableArray alloc] init] autorelease];
+  auto ios_delegate = std::make_unique<flutter::MockIosDelegate>();
+  ios_delegate->on_PostAccessibilityNotification_ =
+      [accessibility_notifications](UIAccessibilityNotifications notification, id argument) {
+        [accessibility_notifications addObject:@{
+          @"notification" : @(notification),
+          @"argument" : argument ? argument : [NSNull null],
+        }];
+      };
+  __block auto bridge =
+      std::make_unique<flutter::AccessibilityBridge>(/*view_controller=*/mockFlutterViewController,
+                                                     /*platform_view=*/platform_view.get(),
+                                                     /*platform_views_controller=*/nil,
+                                                     /*ios_delegate=*/std::move(ios_delegate));
+
+  NSDictionary<NSString*, id>* annotatedEvent = @{@"type" : @"focus", @"nodeId" : @123};
+
+  bridge->HandleEvent(annotatedEvent);
+
+  XCTAssertEqual([accessibility_notifications count], 1ul);
+  XCTAssertEqual([accessibility_notifications[0][@"notification"] unsignedIntValue],
+                 UIAccessibilityLayoutChangedNotification);
+}
+
 - (void)testAnnouncesRouteChangesWhenNoNamesRoute {
   flutter::MockDelegate mock_delegate;
   auto thread_task_runner = CreateNewThread("AccessibilityBridgeTest");