title: Present view controller from app delegate
body: <p>I'm attempting to present a view controller from the app delegate with this code:</p>
  
  <pre><code>- (void)interstitialViewControllerRequestSucceeded:(UIViewController *)interstitialViewController
  {
      [self.window.rootViewController presentViewController:(UIViewController *)interstitialViewController animated:YES completion:NULL];
  }
  </code></pre>
  
  <p>It will display the interstitial on the initial view controller but none of the others. I want it to display on every one attached to a navigation controller.</p>
  
  <p>How can I modify this code to achieve that goal?</p>