Sleep command in tabbar based application is not working properly

Question

HI , i am working on a tab bar navigation based application. once the application loaded i am loading a RSS feed content from a site in its first tab.

I am using autoreleasepol to load the RSS feed inside the view controller and i have the sleeping time as 2 seconds, but the initial loading screen taking more anywhere between 3 to 7 seconds to hide and the tab bar get visible.

can anyone help me to fix the issue

Edit:

 -(void)applicationDidFinishLaunching:(UIApplication *)application 
    {
         sleep(2);
         UINavigationController *nvcontrol =[[UINavigationController alloc] initWithRootViewController:viewController]; 
         [window addSubview:nvcontrol.view];
         [window addSubview:addview.image];
         [window makeKeyAndVisible]; 
    }