Resizing iphone keywindow's main view

Question

Edit: When I start the App without the status bar on top everything behaves as planned. With the status bar I coulnd't get the views to act as I wanted. It looks as if the UINavigationController keeps resizing the content view by subtracting the 20 pixels of the satus bar... I don't know...

Hi, I created a simple UINavigationController-based application. The root view in this navigation controller is a UITableView. At a certain time I want to slide in a 80 pixel high view from the bottom. The whole view on the top (the one that is controlled by the UINavigationController) should resize and get 80 pixel smaller to make room for the new bottom view.

This is basically the code I use to resposition the views:

-(void)showTeaser {
float adHeight = 80;

[adView setFrame:CGRectMake(0.0,self.navigationController.view.bounds.size.height, 320.0, 80.0)];
[[[UIApplication sharedApplication] keyWindow] addSubview:adView];

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.5];
[adView setAlpha:1.0];
[adView setFrame:CGRectMake(0.0,self.navigationController.view.bounds.size.height-adHeight, 320.0, 80.0)];
[self.navigationController.view setFrame:CGRectMake(0.0,0.0, 320.0, self.navigationController.view.bounds.size.height-adHeight)]; 

[self.view setFrame:CGRectMake(0.0, 0, 320.0, self.view.bounds.size.height-adHeight)]; 

[UIView commitAnimations]; }

I lowered the Navigationbar's alpha, set the UITableviewController's view to red. The new view is purple.

This is what happens. First screenshot initial state. Everything is looking normal. Second screenshot shows state after changing the frames. The view of the UITableviewController is always pushed 20 pixel under the Navigationbar. Also, if I try to add more views to the keywindow, they always end up 20 pixel higher than I expect. It almost looks like the keywindow (minus the navigation bar) is pushed up 20 pixel. Edit: No matter to what size I resize the view, it's always 20 pixel.

Do I make a mistake by adding views to the keywindow at all? Shouldn't I do this?

Thanks a lot and kidn regards, Hans