title: UIActivityViewController vs UIDocumentInteractionController in ios
body: <p>I just read some articles on <code>UIActivityViewController</code> and <code>UIDocumentInteractionController</code> in iOS, but I am very confused about how to use them because both seem the same.</p>
  
  <p><strong>So, when do I use  <code>UIActivityViewController</code> or <code>UIDocumentInteractionController</code>?</strong></p>
  
  <p>Is there any difference for <code>Open In...</code> &amp; use <code>UIActivityViewController</code>?</p>
  
  <p>I am very confused about how to use them. Please clarify to me their specific use.</p>