application crashed when I pushing new view controller to self.navigation controller

Question

I have an iOS 5 application. When I want to push view to my navigation controller, the application crashes :(

Here's my appDelegate part:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.


    self.navigationController=[[UINavigationController alloc] init];

    StartViewController *startViewController=[[StartViewController alloc] init];
    [self.navigationController pushViewController:startViewController animated:YES];
    [self.navigationController setNavigationBarHidden:YES];
    [[UIApplication sharedApplication] setStatusBarHidden:YES];

    self.window.backgroundColor = [UIColor whiteColor];
    self.window.rootViewController=self.navigationController;
    [self.window makeKeyAndVisible];
    return YES;
}

Here's my pushing new view controller method:

-(IBAction)startPressed:(id)sender
{
    NSLog(@"startPressed: called");
    //loading RootViewController (mainscreen view)
    RootViewController *rootViewController=[[RootViewController alloc] init];
    [self.navigationController pushViewController:rootViewController animated:YES];
}

Application crashed at a string [self.navigationController pushViewController:rootViewController animated:YES];

Help me, please. How to solve this problem?

Answer 1

Solved the problem. I changed `[self.navigationController pushViewController:vc animated:NO] and debug gave me the warning that the view outlet was not set. So I connected view from interface builder and the problem is gone. Thanks everybody for help