title: How to judge the direction of the UIScrollView is going to scroll?
body: <p><strong>Note</strong>:My question is the direction of the scrollView <strong>will</strong> scroll,not scrolling.That is to say,when user scroll the scrollView,can we get the direction of the scrollView is going to scroll before the scrollView begin scrolling?</p>
  
  <p>Any idea?Thanks in advance.</p>