Fix NullPointerException in ListView

There is a NullPointerException in `handleHorizontalFocusWithinListItem()`
because `selectedView.findFocus()` returns null and then there is no null
check when when the assigned variable `currentFocus` is used, although
`View.findFocus()` states that it may return null.

Change-Id: I6897027e9a2a238d9283e6b9f5146198989fcac0

Author: Kenji Sugimoto

core/java/android/widget/ListView.java

@@ -2385,10 +2385,15 @@ private boolean handleHorizontalFocusWithinListItem(int direction) {
                         (ViewGroup) selectedView, currentFocus, direction);
                 if (nextFocus != null) {
                     // do the math to get interesting rect in next focus' coordinates
-                    currentFocus.getFocusedRect(mTempRect);
-                    offsetDescendantRectToMyCoords(currentFocus, mTempRect);
-                    offsetRectIntoDescendantCoords(nextFocus, mTempRect);
-                    if (nextFocus.requestFocus(direction, mTempRect)) {
+                    Rect focusedRect = mTempRect;
+                    if (currentFocus != null) {
+                        currentFocus.getFocusedRect(focusedRect);
+                        offsetDescendantRectToMyCoords(currentFocus, focusedRect);
+                        offsetRectIntoDescendantCoords(nextFocus, focusedRect);
+                    } else {
+                        focusedRect = null;
+                    }
+                    if (nextFocus.requestFocus(direction, focusedRect)) {
                         return true;
                     }
                 }
@@ -2521,8 +2526,10 @@ private boolean arrowScrollImpl(int direction) {
         if (mItemsCanFocus && (focusResult == null)
                 && selectedView != null && selectedView.hasFocus()) {
             final View focused = selectedView.findFocus();
-            if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) {
-                focused.clearFocus();
+            if (focused != null) {
+                if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) {
+                    focused.clearFocus();
+                }
             }
         }