title: Cocoa Touch - Display an Activity Indicator while loading a UITabBar View
body: <p>I have a UITabBar Application with two views that load large amounts of data from the web in their "viewWillAppear" methods. I want to show a progress bar or an activity indicator while this data is being retrieved, to make sure the user knows the app isn't frozen. </p>
  
  <p>I am aware that this has been asked before. I simply need some clarification on what seems to be a rather <a href="https://stackoverflow.com/questions/1109351">good solution</a>.</p>
  
  <p>I have implimented the code in the example. The question's original asker later solved their problem, by putting the retrieval of data into another "thread". I understand the concept of threads, but I do not know how I would impliment this. </p>
  
  <p>With research, I have found that I need to move all of my heavy data retrieval into a background thread, as all of the UI updating occurs in the main thread. </p>
  
  <p>If one would be so kind as to provide an example for me, I would be very appreciative. I can provide parts of my existing code as necessary. </p>