title: iAd banner doesn't reappear after navigation controller pop
body: <p>I'm running into a problem with my iAd banner view. Initially I have a main menu when my app first loads up. I have an iAd Banner positioned right off the bottom edge of the view and it is animated to appear once my view appears. When I press a button to push to another view controller in the navigation controller hierarchy and then press back to return to the main menu, the iAd does not reappear.It only shows up again when I completely restart the app.</p>
  
  <p>Here is my code: </p>
  
  <pre><code>//MainMenu. h
  @property (strong, nonatomic) IBOutlet ADBannerView *adView;
  @property (nonatomic) BOOL bannerIsVisible;
  
  
   //MainMenu.m
  -(void)viewWillAppear:(BOOL)animated
  {
      bannerIsVisible = NO;
  
      adView.delegate = self;
  
     [self.navigationController setNavigationBarHidden: YES animated:YES];
  
  }
  
  #pragma Begin Ad View Methods
  -(void)bannerViewDidLoadAd:(ADBannerView *)banner
  {
      if(bannerIsVisible == NO)
      {
          NSLog(@"Banner ad loaded");
  
          [UIView beginAnimations:@"animateAdBannerOn" context:NULL];
  
          banner.frame = CGRectOffset(banner.frame, 0, -banner.frame.size.height);
  
          [UIView commitAnimations];
  
          bannerIsVisible = YES;
      }
  }
  
  -(void)viewWillDisappear:(BOOL)animated
  {
      if(bannerIsVisible == YES)
      {
          [UIView beginAnimations:@"animateBannerOff" context:NULL];
  
          adView.frame = CGRectOffset(adView.frame, 0, adView.frame.size.height);
  
          [UIView commitAnimations];
  
          bannerIsVisible = NO;
      }
  }
  
  -(void)bannerView:(ADBannerView *)banner didFailToReceiveAdWithError:(NSError *)error
  {
      NSLog(@"Failed to load the ad in main menu: %@", [error localizedDescription]);
  }
  
  #pragma End Ad View Methods
  </code></pre>
  
  <p>I've tried removing the offset methods and just turning the adView.hidden = YES/NO to see if it was an animation problem but the result is the same. If anyone could offer tips or help it would be greatly appreciated. I've also tried putting the respective code in other methods like viewDidLoad and viewDidDisappear too.</p>