Switching from a normal view to a TabBar Controller - iphone

Question

I build my first iPhone application and I have a problem with switching views.
First, I have two views (login, registration) which switch via "presentModalViewController:animated:".
But if someone logged in, there must be a new kind of view. I wanna have an UITabBar at the bottom (tab bar controller). But this does not work. I tried to create a new AppDelegate, so that I can use tutorials like this one which need a AppDelegate:
http://www.youtube.com/watch?v=LBnPfAtswgw&feature=player_embedded
The switch to the new controller is done like this:
startViewController = [[StartViewController alloc] initWithNibName:#"StartView" bundle:nil];
[UIView beginAnimations:#"View Curl" context:nil];
[UIView setAnimationDuration:2.0];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.view cache:YES];
[self.view addSubview:startViewController.view];
[UIView commitAnimations];
The screen is white, because the shown view is the UIView in my StartView.xib. There I have the new AppDelegate, File's owner, View, TabBarController. But only the UIView is loaded and not the TabBarController.
Do you have an idea how I could this problem?
Thanks & Best Regards.

Answer 1

I might suggest you start with a TabBarController, and if the username/password is not set, the active ViewController executes presentModalViewController:animated: to display the login/registration viewsControllers in modal mode (hidding the underliying TabBarController).
Here is some sample code for doing it programmatically.
- (void)applicationDidFinishLaunching:(UIApplication *)application {
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
[window setBackgroundColor:[UIColor whiteColor]];
tabBarController = [[UITabBarController alloc] init];
aViewController = [[aViewController alloc] init];
UINavigationController *aNavController = [[[UINavigationController alloc] initWithRootViewController:aViewController] autorelease];
aNavController.navigationBar.barStyle = UIBarStyleBlackTranslucent;
[aViewController release];
tabBarController.viewControllers = [NSArray arrayWithObjects: aNavController, nil];
// Add the tab bar controller's current view as a subview of the window
[window addSubview:tabBarController.view];
if(userNotLoggedIn){
[self displayLoginViewController];
}
[window makeKeyAndVisible];
}
- (void)displayLoginViewController {
LoginViewController *controller = [[LoginViewController alloc] init];
// setup controller
[self.tabBarController presentModalViewController:controller animated:NO];
[controller release];
}