UIViewController covering UINavigationBar

I have a UITabBarController with 2 items, where each item is pointing to a view controller of type Navigation Controller.

The second item is a login page to my web service.

A User that did not logged in will see a login page -> "LoginViewController".

If a user is already logged in, a different view will be there -> "LoggedViewController".

On Startup, in my AppDelegate i am checking if the user already logged or need to login and i change the views.

if (!logged) {
LoginViewController * nextView = [[[LoginViewController alloc] initWithNibName:@"LoginViewController" bundle:nil] autorelease];

NSMutableArray * tabBarRootViews = [[NSMutableArray alloc] initWithArray:self.tabBarController.viewControllers];

[tabBarRootViews replaceObjectAtIndex:1 withObject:nextView];

[sel开发者_StackOverflow社区f.tabBarController setViewControllers:tabBarRootViews animated:YES];
} else {
// Same if the user is logged only diff view
}

When the view is presented, It overlaps the UINavigationBar. I believe that the issue is that i am trying to replace a UINavigationController with a UIViewController, but i can't put my finger on the problem.

1. Any idea how to solve it? (I want to see both the UITabBar and UINavigationBar and the UIViewController in the middle)
2. Is that the correct way to change ViewControllers? Should i Use PresentModalView Instead?

Thanks!

I fixed it by keeping the UINavigationController as is and push a view controller according to the logged boolean.