private void updateVisibleRows(int mask) {
   if (listView == null) {
     return;
   }
   int count = listView.getChildCount();
   for (int a = 0; a < count; a++) {
     View child = listView.getChildAt(a);
     if (child instanceof ChatOrUserCell) {
       ((ChatOrUserCell) child).update(mask);
     }
   }
 }