title: Need some explanation about asynchronous tasks
body: <p>Here is one of the things I understand the least with iOS programming. When I push a view with my navigation controller, I need to read a text file with a huge amount of data that takes around 2-3 seconds to process, while creating the new view.</p>
  
  <p>So I want to process this file asynchronously, in order to show an ActivityIndicator at the same time.</p>
  
  <p>I have already used, in other projects, connection functions (<code>connection</code>, <code>connectionDidFinishLoading</code>...), but here what I want to do is different because data is already in my project files, so connection is not needed. </p>
  
  <p>Thanks for your help and advices.</p>