title: UIPasteboard - copy a few string from other app at one time
body: <p>In an app called 'A', I copyed three strings to system pasteboard at different times. how can I copy them to my app at once.</p>
  
  <ol>
  <li>go to safari copy a string: “a”</li>
  <li>then still in the safari, copy another string: “ab”</li>
  <li>go to my app. I already know I can get string “ab” very easy, just like you said. but I want to get both “a” and “ab”.</li>
  </ol>
  
  <p>I konw an app called 'Pin' can store the pasteboard history items.how does it do that?</p>
  
  <p>Any help would be very much appreciated.</p>