Adding a Navigation Controller to a View based Application adds top margin

I am trying to programmatically add a Navigation Controller to my View based Applicat开发者_开发问答ion. This is the code I am using (this code gets called after a button press in a view controller):

MainMenu *control = [[MainMenu alloc] initWithNibName: @"MainMenu" bundle: nil];
UINavigationController *navControl = [[UINavigationController alloc] initWithRootViewController: control];
[self.view addSubview:navControl.view];
[control release];

That works, but this ends up happening:

Notice the odd margin above the Navigation control.... My View controller that I am adding the Navigation Controller to has a gray background which you can see.

Any ideas??

If you have a better way of adding a Navigation Controller to a View based Application I am very open to suggestions!

Thank you in advance!

Thank you both for your response, but unfortunately, wantsFullScreenLayout set to YES or NO in the code didn't have any effect. I was able to push the Navigation Controller up by 20 using this line of code:

self.navigationController.navigationBar.frame = CGRectOffset(self.navigationController.navigationBar.frame, 0.0, -20.0);

but then what happened was that the View Controller did not move up with the Navigation bar and left a gap below the Navigation Bar and the View Controller. What eventually worked was checking the Wants Full Screen checkbox in IB in the MainWindow view controller that is automatically generated when you set up a view based application.

The gap you are seeing is the same height as a status bar. Check the status bar settings in your NIB file.

Chances are you want to make the UINavigationController the root view controller for the window, rather than whichever view controller you have now. That would be the better way to do it.

The reason you're seeing that extra margin at the top is because UINavigationController normally expects that it will be sized to fill the entire screen (except perhaps a tab bar at the bottom, if it's inside a UITabBarController), and therefore expects that the top edge of its view will be under the status bar if the status bar is visible. Therefore, it places its navigation bar 20 pixels below the top of its view to leave space for the status bar, without bothering to check whether its view actually is under the status bar. Interestingly, sometimes a re-layout operation will perform this check, but that's unreliable. What I've found works well in a situation like this is to set the UINavigationController's wantsFullScreenLayout property to NO. Then ti doesn't try to leave room for the status bar, so everything works as expected.

I've been struggling with this same issue this morning. Since setting the wantsFullScreenLayout property doesn't seem to have any effect, I resorted to using a little subclass, which worked fine:

@interface MyNavigationController : UINavigationController
@end

@implementation MyNavigationController

- (BOOL)wantsFullScreenLayout;
{
    return NO;
}

@end

Its so simple to remove that gap..

self.navigationBar.view.frame = CGRectMake(0, -20, 320, 480);