self.navigationController.tabBarController.selectedIndex not working

Question

I have a UITabBarController which containing 4 different UIViewControllers.

On first tab there is a UINavigationViewController

Answer 1

Try moving your tab switch code to viewDidLoad

I verified that this works on the built in Tabbed Application template project in xcode 4

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.tabBarController.selectedIndex = 1;
}

I'd also take a look at your AppDelegate class for something along the lines of this

self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];
self.window.rootViewController = self.tabBarController;

If you don't see these lines anywhere then you'll want to find where else in your code the UITabBarViewController is being initialized and use that object pointer instead.