Only save focus in keyboard navigation clusters when appropriate

 - tabbing forward/backward should not save cluster focus. If
   focus leaves a cluster due to normal forward/backward navigation
   the cluster focus is cleared.
 - directional arrows or cluster jumps (meta+tab) will save focus
   in the cluster so that cluster-jumping back will restore it.

Also fixed a couple small bugs: focusable viewgroups wouldn't save
properly, focusIncluster wasn't cleared properly.

Bug: 35274351
Test: Added CTS test for this behavior.
Change-Id: Ie86218d70b0fc3aa1a709e613a2761a65ab12500

2 files changed, 36 insertions, 12 deletions

diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index bcf0b9060ed7..3e50a47d05d2 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -6468,7 +6468,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
 
             if (mParent != null) {
                 mParent.requestChildFocus(this, this);
-                setFocusedInCluster();
+                updateFocusedInCluster(oldFocus, direction);
             }
 
             if (mAttachInfo != null) {
@@ -9834,22 +9834,47 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
      * @hide
      */
     public final void setFocusedInCluster() {
-        View top = findKeyboardNavigationCluster();
-        if (top == this) {
+        setFocusedInCluster(findKeyboardNavigationCluster());
+    }
+
+    private void setFocusedInCluster(View cluster) {
+        if (this instanceof ViewGroup) {
+            ((ViewGroup) this).mFocusedInCluster = null;
+        }
+        if (cluster == this) {
             return;
         }
         ViewParent parent = mParent;
         View child = this;
         while (parent instanceof ViewGroup) {
-            ((ViewGroup) parent).setFocusedInCluster(child);
-            if (parent == top) {
-                return;
+            ((ViewGroup) parent).mFocusedInCluster = child;
+            if (parent == cluster) {
+                break;
             }
             child = (View) parent;
             parent = parent.getParent();
         }
     }
 
+    private void updateFocusedInCluster(View oldFocus, @FocusDirection int direction) {
+        if (oldFocus != null) {
+            View oldCluster = oldFocus.findKeyboardNavigationCluster();
+            View cluster = findKeyboardNavigationCluster();
+            if (oldCluster != cluster) {
+                // Going from one cluster to another, so save last-focused.
+                // This covers cluster jumps because they are always FOCUS_DOWN
+                oldFocus.setFocusedInCluster(oldCluster);
+                if (direction == FOCUS_FORWARD || direction == FOCUS_BACKWARD) {
+                    // This is a result of ordered navigation so consider navigation through
+                    // the previous cluster "complete" and clear its last-focused memory.
+                    if (oldFocus.mParent instanceof ViewGroup) {
+                        ((ViewGroup) oldFocus.mParent).clearFocusedInCluster(oldFocus);
+                    }
+                }
+            }
+        }
+    }
+
     /**
      * Returns whether this View should receive focus when the focus is restored for the view
      * hierarchy containing this view.
diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index 1977ef5ae989..d3d46cb4f44b 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -143,7 +143,7 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
     // that is or contains a default-focus view.
     private View mDefaultFocus;
     // The last child of this ViewGroup which held focus within the current cluster
-    private View mFocusedInCluster;
+    View mFocusedInCluster;
 
     /**
      * A Transformation used when drawing children, to
@@ -807,10 +807,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         return mDefaultFocus != null || super.hasDefaultFocus();
     }
 
-    void setFocusedInCluster(View child) {
-        mFocusedInCluster = child;
-    }
-
     /**
      * Removes {@code child} (and associated focusedInCluster chain) from the cluster containing
      * it.
@@ -826,8 +822,11 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         ViewParent parent = this;
         do {
             ((ViewGroup) parent).mFocusedInCluster = null;
+            if (parent == top) {
+                break;
+            }
             parent = parent.getParent();
-        } while (parent != top && parent instanceof ViewGroup);
+        } while (parent instanceof ViewGroup);
     }
 
     @Override