title: How to use PDFView and PDFThumbnailView in iOS?
body: <p>I found a PDFView and PDFThumbnailView in Object Library like this pic:</p>
  
  <p><img src="https://i.stack.imgur.com/AI9MZ.png" alt="enter image description here"></p>
  
  <p>But my question is how to use it ??? I can't drag it in xib , and no idea to create a PDFView by code .</p>
  
  <p>Any answer or tutorial will be help.</p>