How to get rid of gap when I add my custom UIViewController to window?

I'm getting this gap at the bottom of my window after I add the view o开发者_JAVA技巧f a custom UIViewController. The gap goes away as the view is shifted down after I move to another view and then back.

Here is the code in the app delegate:

- (void)applicationDidFinishLaunching:(UIApplication *)application {    

    // Override point for customization after application launch
    CustomViewController *gvc = [[CustomViewController alloc] init];
    self.customViewController = gvc;
    [gvc release];

    [window addSubview:customViewController.view];
    [window makeKeyAndVisible];
}

"CustomViewController" is used as a root view controller to simply coordinate which other UIViewControllers to display. As such I simply set its view = to that of the first ViewController's view needed like so:

 - (void)loadView { 
     UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
     self.view = v;
     [v release];

     // Add the HomeViewController to the top of the stack
     MainViewController *mvc = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];
     mvc.delegate = self;
     self.mainViewController = mvc;
     [mvc release];

     [self.view addSubview:self.mainViewController.view];
 }

I've tried a bunch of things including what you see here with no luck. Any ideas?

thanks

---

This line

UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];

should be ...

UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0, 20, 320, 460)];

Good times.