title: Handling applicationDidBecomeActive - "How can a view controller respond to the app becoming Active?"
body: <p>I have the <code>UIApplicationDelegate</code> protocol in my main AppDelegate.m class, with the <code>applicationDidBecomeActive</code> method defined. </p>
  
  <p>I want to call a method when the application returns from the background, but the method is in another view controller. How can I check which view controller is currently showing in the <code>applicationDidBecomeActive</code> method and then make a call to a method within that controller?</p>