Restricting navigation into and from clusters.

Tabbing loops inside cluster. Tabbing outside of clusters (i.e. in
the default cluster) won’t enter clusters. Initial focus won’t go
into a cluster.

Arrows work like before.

Bug: 32151632
Test: Manual checks. CTS test will be added after feature freeze.
Change-Id: Icecbd75394e2dd4afe2e1c4e6bc9ac64f6785699

1 files changed, 13 insertions, 3 deletions

diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index c83298b873a2..7340cf712ca0 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -869,10 +869,13 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
      */
     @Override
     public View focusSearch(View focused, int direction) {
-        if (isRootNamespace()) {
+        if (isRootNamespace()
+                || isKeyboardNavigationCluster()
+                && (direction == FOCUS_FORWARD || direction == FOCUS_BACKWARD)) {
             // root namespace means we should consider ourselves the top of the
             // tree for focus searching; otherwise we could be focus searching
-            // into other tabs.  see LocalActivityManager and TabHost for more info
+            // into other tabs.  see LocalActivityManager and TabHost for more info.
+            // Cluster's root works same way for the forward and backward navigation.
             return FocusFinder.getInstance().findNextFocus(this, focused, direction);
         } else if (mParent != null) {
             return mParent.focusSearch(focused, direction);
@@ -1104,6 +1107,12 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
 
     @Override
     public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
+        if (isKeyboardNavigationCluster()
+                && (direction == FOCUS_FORWARD || direction == FOCUS_BACKWARD) && !hasFocus()) {
+            // A cluster cannot be focus-entered from outside using forward/backward navigation.
+            return;
+        }
+
         final int focusableCount = views.size();
 
         final int descendantFocusability = getDescendantFocusability();
@@ -3026,7 +3035,8 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         final View[] children = mChildren;
         for (int i = index; i != end; i += increment) {
             View child = children[i];
-            if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
+            if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE
+                    && !child.isKeyboardNavigationCluster()) {
                 if (child.requestFocus(direction, previouslyFocusedRect)) {
                     return true;
                 }