Sets focus before sending a11y focus event in Android

Author: chunhtai

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

@@ -1020,28 +1020,33 @@ public boolean performAction(
         }
       case AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS:
         {
+          // Focused semantics node must be reset before sending the
+          // TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED event. Otherwise,
+          // TalkBack may think the node is still focused.
+          accessibilityFocusedSemanticsNode = null;
+          embeddedAccessibilityFocusedNodeId = null;
           accessibilityChannel.dispatchSemanticsAction(
               virtualViewId, Action.DID_LOSE_ACCESSIBILITY_FOCUS);
           sendAccessibilityEvent(
               virtualViewId, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
-          accessibilityFocusedSemanticsNode = null;
-          embeddedAccessibilityFocusedNodeId = null;
           return true;
         }
       case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS:
         {
-          accessibilityChannel.dispatchSemanticsAction(
-              virtualViewId, Action.DID_GAIN_ACCESSIBILITY_FOCUS);
-          sendAccessibilityEvent(virtualViewId, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
-
           if (accessibilityFocusedSemanticsNode == null) {
             // When Android focuses a node, it doesn't invalidate the view.
             // (It does when it sends ACTION_CLEAR_ACCESSIBILITY_FOCUS, so
             // we only have to worry about this when the focused node is null.)
             rootAccessibilityView.invalidate();
           }
+          // Focused semantics node must be set before sending the TYPE_VIEW_ACCESSIBILITY_FOCUSED
+          // event. Otherwise, TalkBack may think the node is not focused yet.
           accessibilityFocusedSemanticsNode = semanticsNode;
 
+          accessibilityChannel.dispatchSemanticsAction(
+              virtualViewId, Action.DID_GAIN_ACCESSIBILITY_FOCUS);
+          sendAccessibilityEvent(virtualViewId, AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+
           if (semanticsNode.hasAction(Action.INCREASE)
               || semanticsNode.hasAction(Action.DECREASE)) {
             // SeekBars only announce themselves after this event.

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

@@ -5,6 +5,7 @@
 package io.flutter.view;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Matchers.eq;
@@ -46,6 +47,7 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
+import org.mockito.invocation.InvocationOnMock;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.RuntimeEnvironment;
 import org.robolectric.annotation.Config;
@@ -798,6 +800,122 @@ public void itCanPredictSetSelection() {
     assertEquals(nodeInfo.getTextSelectionEnd(), expectedEnd);
   }
 
+  @Test
+  public void itSetsFocusedNodeBeforeSendingEvent() {
+    AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);
+    AccessibilityViewEmbedder mockViewEmbedder = mock(AccessibilityViewEmbedder.class);
+    AccessibilityManager mockManager = mock(AccessibilityManager.class);
+    View mockRootView = mock(View.class);
+    Context context = mock(Context.class);
+    when(mockRootView.getContext()).thenReturn(context);
+    when(context.getPackageName()).thenReturn("test");
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(
+            /*rootAccessibilityView=*/ mockRootView,
+            /*accessibilityChannel=*/ mockChannel,
+            /*accessibilityManager=*/ mockManager,
+            /*contentResolver=*/ null,
+            /*accessibilityViewEmbedder=*/ mockViewEmbedder,
+            /*platformViewsAccessibilityDelegate=*/ null);
+
+    ViewParent mockParent = mock(ViewParent.class);
+    when(mockRootView.getParent()).thenReturn(mockParent);
+    when(mockManager.isEnabled()).thenReturn(true);
+
+    TestSemanticsNode root = new TestSemanticsNode();
+    root.id = 0;
+    root.label = "root";
+
+    TestSemanticsUpdate testSemanticsUpdate = root.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+
+    class Verifier {
+      public Verifier(AccessibilityBridge accessibilityBridge) {
+        this.accessibilityBridge = accessibilityBridge;
+      }
+
+      public AccessibilityBridge accessibilityBridge;
+      public boolean verified = false;
+
+      public boolean verify(InvocationOnMock invocation) {
+        AccessibilityEvent event = (AccessibilityEvent) invocation.getArguments()[1];
+        assertEquals(event.getEventType(), AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+        // The accessibility focus must be set before sending out
+        // the TYPE_VIEW_ACCESSIBILITY_FOCUSED event.
+        AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+        assertTrue(nodeInfo.isAccessibilityFocused());
+        verified = true;
+        return true;
+      }
+    };
+    Verifier verifier = new Verifier(accessibilityBridge);
+    when(mockParent.requestSendAccessibilityEvent(eq(mockRootView), any(AccessibilityEvent.class)))
+        .thenAnswer(invocation -> verifier.verify(invocation));
+    accessibilityBridge.performAction(0, AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null);
+    assertTrue(verifier.verified);
+  }
+
+  @Test
+  public void itClearsFocusedNodeBeforeSendingEvent() {
+    AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);
+    AccessibilityViewEmbedder mockViewEmbedder = mock(AccessibilityViewEmbedder.class);
+    AccessibilityManager mockManager = mock(AccessibilityManager.class);
+    View mockRootView = mock(View.class);
+    Context context = mock(Context.class);
+    when(mockRootView.getContext()).thenReturn(context);
+    when(context.getPackageName()).thenReturn("test");
+    AccessibilityBridge accessibilityBridge =
+        setUpBridge(
+            /*rootAccessibilityView=*/ mockRootView,
+            /*accessibilityChannel=*/ mockChannel,
+            /*accessibilityManager=*/ mockManager,
+            /*contentResolver=*/ null,
+            /*accessibilityViewEmbedder=*/ mockViewEmbedder,
+            /*platformViewsAccessibilityDelegate=*/ null);
+
+    ViewParent mockParent = mock(ViewParent.class);
+    when(mockRootView.getParent()).thenReturn(mockParent);
+    when(mockManager.isEnabled()).thenReturn(true);
+
+    TestSemanticsNode root = new TestSemanticsNode();
+    root.id = 0;
+    root.label = "root";
+
+    TestSemanticsUpdate testSemanticsUpdate = root.toUpdate();
+    testSemanticsUpdate.sendUpdateToBridge(accessibilityBridge);
+    // Set the focus on root.
+    accessibilityBridge.performAction(0, AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null);
+    AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+    assertTrue(nodeInfo.isAccessibilityFocused());
+
+    class Verifier {
+      public Verifier(AccessibilityBridge accessibilityBridge) {
+        this.accessibilityBridge = accessibilityBridge;
+      }
+
+      public AccessibilityBridge accessibilityBridge;
+      public boolean verified = false;
+
+      public boolean verify(InvocationOnMock invocation) {
+        AccessibilityEvent event = (AccessibilityEvent) invocation.getArguments()[1];
+        assertEquals(
+            event.getEventType(), AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
+        // The accessibility focus must be cleared before sending out
+        // the TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED event.
+        AccessibilityNodeInfo nodeInfo = accessibilityBridge.createAccessibilityNodeInfo(0);
+        assertFalse(nodeInfo.isAccessibilityFocused());
+        verified = true;
+        return true;
+      }
+    };
+    Verifier verifier = new Verifier(accessibilityBridge);
+    when(mockParent.requestSendAccessibilityEvent(eq(mockRootView), any(AccessibilityEvent.class)))
+        .thenAnswer(invocation -> verifier.verify(invocation));
+    accessibilityBridge.performAction(
+        0, AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS, null);
+    assertTrue(verifier.verified);
+  }
+
   @Test
   public void itCanPredictCursorMovementsWithGranularityWord() {
     AccessibilityChannel mockChannel = mock(AccessibilityChannel.class);