title: UINavigationController title is not displayed?
body: <p>I have normal UIViewController ,inwhich I added UINavigationControllerDelegate,i
  added as following in willappear?but it did not work?</p>
  
  <pre><code>    [self.navigationController setNavigationBarHidden:NO animated:YES];
      self.navigationController.navigationItem.title = @"hai";
  </code></pre>