GameKit

Use GameKit for Game Center authentication, competition, matchmaking, social surfaces, and saved-game handoffs; keep rendering, board logic, and full SharePlay group-activity design in their owning framework skills.

Contents

• Authentication
• Access Point
• Dashboard
• Leaderboards
• Achievements
• Real-Time Multiplayer
• Turn-Based Multiplayer
• Common Mistakes
• Review Checklist
• References

Authentication

All GameKit features require the local player to authenticate first. Set the authenticateHandler on GKLocalPlayer.local early in the app lifecycle. GameKit calls the handler multiple times during initialization.

import GameKit

func authenticatePlayer() {
    GKLocalPlayer.local.authenticateHandler = { viewController, error in
        if let viewController {
            // Present so the player can sign in or create an account.
            present(viewController, animated: true)
            return
        }
        if let error {
            // Player could not sign in. Disable Game Center features.
            disableGameCenter()
            return
        }

        // Player authenticated. Check restrictions before starting.
        let player = GKLocalPlayer.local

        if player.isUnderage {
            hideExplicitContent()
        }
        if player.isMultiplayerGamingRestricted {
            disableMultiplayer()
        }
        if player.isPersonalizedCommunicationRestricted {
            disableInGameChat()
        }

        configureAccessPoint()
    }
}

Guard on GKLocalPlayer.local.isAuthenticated before calling any GameKit API. For server-side identity verification, see references/gamekit-patterns.md.

Access Point