Handling getLastItem when the folder is closed

Change-Id: I6afebd7c0a92edb25e3658e7f860244d7457c852
diff --git a/src/com/android/launcher3/FolderCellLayout.java b/src/com/android/launcher3/FolderCellLayout.java
index e6e9199..b354ec7 100644
--- a/src/com/android/launcher3/FolderCellLayout.java
+++ b/src/com/android/launcher3/FolderCellLayout.java
@@ -245,7 +245,13 @@
     @Override
     public View getLastItem() {
         int lastRank = getShortcutsAndWidgets().getChildCount() - 1;
-        return getShortcutsAndWidgets().getChildAt(lastRank % getCountX(), lastRank / getCountX());
+        // count can be zero if the folder is not yet laid out.
+        int count = getCountX();
+        if (count > 0) {
+            return getShortcutsAndWidgets().getChildAt(lastRank % count, lastRank / count);
+        } else {
+            return getShortcutsAndWidgets().getChildAt(lastRank);
+        }
     }
 
     @Override