How to programmatically "follow" a Twitter feed in an iOS app?

I want to add code to my iOS app which prompts users to "follow" my app's Twitter feed after they use the program X number of times. However I want to keep it as simple as possible for the user. What are the best practices for programmatically "follow" a Twitter feed? Right now, I have a link to my Twitter feed in the "Help" screen, but I want to make it more visible to the user and try to get more followers.

EDIT: To clarify, I already know how to pop up a UIAlert after the user opens the app 1 times. I am interested in friction-free ways to get the user to "follow" my twitter feed. If possible, I'd l开发者_StackOverflowike it so that users don't actually have to enter their username & password if they are already logged into Twitter. Is this possible?

MGTwitterEngine implements this method

- (NSString *)enableUpdatesFor:(NSString *)username; // friendships/create (follow username)

I do not use Twitter, but I think this is what you're looking for.

You could keep a count of how many times didFinishLaunchingWithOptions: is fired by storing a count in NSUserDefaults. If the count (after increment) is a certain limit, then show a UIAlertView that sends them to your twitter page (or alternatively, uses MGTwitterEngine to log-in and follow you).