title: UIActivityView, UITableView MonoTouch
body: <p>I have a class inheriting from UITableView, which shows results from an XML feed. I want to add a UIActivityView to that page. Here is my desired functionality:</p>
  
  <ol>
  <li><p>When the page is loading, the TableView is hidden. Only the UIActivityView is available. The UIActivityView is centered on screen.</p></li>
  <li><p>When the content is done, the UIActivityView disappears. The TableView shows up.</p></li>
  </ol>
  
  <p>How can this be done? </p>