Question

What is the right way to change XIB View which loaded at app start depending on some app settings. Of course I know how to get all settings I need.

Answer 1

In your application’s delegate, in the method

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
if(yourSettings)
     myViewController = [[MyViewController alloc] initWithNibName:@"FirstNibName" bundle:nil];
else
     myViewController = [[MyViewController alloc] initWithNibName:@"SecondNibName" bundle:nil];
self.window.rootViewController = self.myViewController;
[self.window makeKeyAndVisible];
return YES;
}

And that’s it. Probably you may want to save your settings in your user defaults so you can load the view properly.

However, I would use 2 different view controllers, as you probably want them to do different things, not just modify some graphics.

EDIT-

Let me see if I understand. You will always load the first view controller and, if some conditions are met, you modally want to present the second view controller that will get dismissed at some point, returning the user to the first view controller. If this is the case, I suggest you move the code in your first view controller, in viewDidLoad or better yet in viewDidAppear, as this view controller will always get loaded. Also this way the user can see that he will eventually go to that view controller. I use something like this in applications the user needs to login to so that it will be obvious for him that he cannot continue until he does login.

I can’t say that this is the right way to do it, because it’s up to the programmer how he arranges his code, but it would seem to me that the place that controls what view and how it appears belongs in a view controller and not in the delegate, especially considering that your first view controller always gets loaded. It should be up to that view controller to see if it presents the second one or not.