Accessibility focus traversal in virtual nodes.

1. Finished the implementation of support for maintaining
   accessibility focus in view with virtual descendants.

2. Finished the NumberPicker implementation of virtual
   subtree such that all requred attributes are reported
   and ensuring that it support accessibility focus in
   its virtual descentants.

3. Fixed a bug where if a predecessor of the view that is
   accessiiblity focused is removed the accessibliity focus
   host in ViewRootImpl is not cleared leading to a crash
   when trying to draw the accessibility focus highlight.:

bug:6472646
bug:6433864

Change-Id: I3645642b87b4a26025c0b2ba9dfaad92d11a48f1

1 files changed, 74 insertions, 5 deletions

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index f86e036e3c6b..553abac51223 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -488,7 +488,9 @@ public final class ViewRootImpl implements ViewParent,
                 mFallbackEventHandler.setView(view);
                 mWindowAttributes.copyFrom(attrs);
                 attrs = mWindowAttributes;
-                
+
+                setAccessibilityFocusedHost(null);
+
                 if (view instanceof RootViewSurfaceTaker) {
                     mSurfaceHolderCallback =
                             ((RootViewSurfaceTaker)view).willYouTakeTheSurface();
@@ -556,6 +558,7 @@ public final class ViewRootImpl implements ViewParent,
                     mInputChannel = null;
                     mFallbackEventHandler.setView(null);
                     unscheduleTraversals();
+                    setAccessibilityFocusedHost(null);
                     throw new RuntimeException("Adding window failed", e);
                 } finally {
                     if (restore) {
@@ -575,6 +578,7 @@ public final class ViewRootImpl implements ViewParent,
                     mAdded = false;
                     mFallbackEventHandler.setView(null);
                     unscheduleTraversals();
+                    setAccessibilityFocusedHost(null);
                     switch (res) {
                         case WindowManagerImpl.ADD_BAD_APP_TOKEN:
                         case WindowManagerImpl.ADD_BAD_SUBWINDOW_TOKEN:
@@ -635,8 +639,6 @@ public final class ViewRootImpl implements ViewParent,
                 if (view.getImportantForAccessibility() == View.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
                     view.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
                 }
-
-                setAccessibilityFocusedHost(null);
             }
         }
     }
@@ -2543,11 +2545,51 @@ public final class ViewRootImpl implements ViewParent,
     }
 
     void setAccessibilityFocusedHost(View host) {
-        if (mAccessibilityFocusedHost != null && mAccessibilityFocusedVirtualView == null) {
+        // If we have a virtual view with accessibility focus we need
+        // to clear the focus and invalidate the virtual view bounds.
+        if (mAccessibilityFocusedVirtualView != null) {
+
+            AccessibilityNodeInfo focusNode = mAccessibilityFocusedVirtualView;
+            View focusHost = mAccessibilityFocusedHost;
+            focusHost.clearAccessibilityFocusNoCallbacks();
+
+            // Wipe the state of the current accessibility focus since
+            // the call into the provider to clear accessibility focus
+            // will fire an accessibility event which will end up calling
+            // this method and we want to have clean state when this
+            // invocation happens.
+            mAccessibilityFocusedHost = null;
+            mAccessibilityFocusedVirtualView = null;
+
+            AccessibilityNodeProvider provider = focusHost.getAccessibilityNodeProvider();
+            if (provider != null) {
+                // Invalidate the area of the cleared accessibility focus.
+                focusNode.getBoundsInParent(mTempRect);
+                focusHost.invalidate(mTempRect);
+                // Clear accessibility focus in the virtual node.
+                final int virtualNodeId = AccessibilityNodeInfo.getVirtualDescendantId(
+                        focusNode.getSourceNodeId());
+                provider.performAction(virtualNodeId,
+                        AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS, null);
+            }
+        }
+        if (mAccessibilityFocusedHost != null) {
+            // Clear accessibility focus in the view.
             mAccessibilityFocusedHost.clearAccessibilityFocusNoCallbacks();
         }
+
+        // Set the new focus host.
         mAccessibilityFocusedHost = host;
-        mAccessibilityFocusedVirtualView = null;
+
+        // If the host has a provide find the virtual descendant that has focus.
+        if (mAccessibilityFocusedHost != null) {
+            AccessibilityNodeProvider provider =
+                mAccessibilityFocusedHost.getAccessibilityNodeProvider();
+            if (provider != null) {
+                mAccessibilityFocusedVirtualView = provider.findAccessibilityFocus(View.NO_ID);
+                return;
+            }
+        }
     }
 
     public void requestChildFocus(View child, View focused) {
@@ -2633,6 +2675,8 @@ public final class ViewRootImpl implements ViewParent,
 
         destroyHardwareRenderer();
 
+        setAccessibilityFocusedHost(null);
+
         mView = null;
         mAttachInfo.mRootView = null;
         mAttachInfo.mSurface = null;
@@ -4608,6 +4652,31 @@ public final class ViewRootImpl implements ViewParent,
         if (mView == null) {
             return false;
         }
+        // Watch for accessibility focus change events from virtual nodes
+        // to keep track of accessibility focus being on a virtual node.
+        final int eventType = event.getEventType();
+        switch (eventType) {
+            case AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED: {
+                final long sourceId = event.getSourceNodeId();
+                // If the event is not from a virtual node we are not interested.
+                final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId(sourceId);
+                if (virtualViewId == AccessibilityNodeInfo.UNDEFINED) {
+                    break;
+                }
+                final int realViewId = AccessibilityNodeInfo.getAccessibilityViewId(sourceId);
+                View focusHost = mView.findViewByAccessibilityId(realViewId);
+                setAccessibilityFocusedHost(focusHost);
+            } break;
+            case AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED: {
+                final long sourceId = event.getSourceNodeId();
+                // If the event is not from a virtual node we are not interested.
+                final int virtualViewId = AccessibilityNodeInfo.getVirtualDescendantId(sourceId);
+                if (virtualViewId == AccessibilityNodeInfo.UNDEFINED) {
+                    break;
+                }
+                setAccessibilityFocusedHost(null);
+            } break;
+        }
         mAccessibilityManager.sendAccessibilityEvent(event);
         return true;
     }