public void moveToTop(Pinger pinger){
  mPingers.remove(pinger);
  mPingers.add(0,pinger);
  notifyDataSetChanged();
}

public void moveToTop ( Pinger pinger ) { mPingers . remove ( pinger ) ; mPingers . add ( 0 , pinger ) ; notifyDataSetChanged ( ) ; }
move a pinger to the top of the list .
