Show ViewController and NavigationController

gistfile1.m

+ (void)showViewControllerAndNavigationControllerFromParentViewController:(UIViewController *)parentVC
{
    AViewController *vc = [[[AViewController alloc] init] autorelease];

    UINavigationController* nc = [[[UINavigationController alloc]
                                   initWithRootViewController:vc] autorelease];
    nc.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

    vc.navigationController = nc;
    vc.navigationBar = nc.navigationBar;
    [parentVC presentModalViewController:nc animated:YES];
}