Beginning iOS Game Center and Game Kit: For iPhone, iPad, and iPod touch

GKTurnBasedEventHandler

The GKTurnedBasedEventHandler is a delegate protocol that is responsible for handling important messages related to turn-based games. To set a delegate for events, use the following code.

    [[GKTurnBasedEventHandler sharedTurnBasedEventHandler] setDelegate: self];

The protocol has three optional methods.

• handleInviteFromGameCenter: When your delegate receives this method, it should populate a new GKMatchRequest with the playersToInvite that are passed in through the method. You then need to begin a new match or present the matchmaker GUI. This method is called when the user accepts a match invite from a friend.
• handleTurnEventForMatch: Your delegate receives this message when the user has accepted a push notification ...