What’s new in Game Center: Widgets, friends, and multiplayer improvements

8:23 - Friending API

// Call Friend Requests API to present friend request view from a view controller, when player click on Add Friends Button in your game
let error = GKLocalPlayer.local
.presentFriendRequestCreatorFromViewController(using: navigationController)

if error != nil {
    print("Fail to send friend request with error: \(error!.localizedDescription).")
}

11:47 - loadFriendsAuthorizationStatus

// Checking authorization
GKLocalPlayer.local.loadFriendsAuthorizationStatus { (authorizationStatus, error) in
    guard error == nil else {
       // Error handling
       print(“Fail to load friends list with error: \(error!.localizedDescription).”)
       return
    }

    // Handle GKFriendsAuthorizationStatus
    switch authorizationStatus {
      case .notDetermined:
         // Player have not made a choice on friends list sharing
      case .denied:
         // Player have denied your request to access their friends list
      case .restricted:
         // You should delete collected player data from your end
      case .authorized:
         // Player have authorized your request to access their friends list
    }
}

12:53 - loadFriends

func loadFriendsOnProgressionMap() async {
    do {
        let friends = try await GKLocalPlayer.local.loadFriends()
        if friends.count > 0 {
            let leaderboards = try await GKLeaderboard.loadLeaderboards(IDs: [“progress"])
            if let leaderboard = leaderboards.first {
                let entries = try await leaderboard.loadEntries(for: friends, timeScope: .allTime)
               for entry in entries.1 {
                    let avatar = try await entry.player.loadPhoto(for: .normal)
                    let name = entry.player.displayName
                    let friendLevel = entry.score
                    // Display player on progression map
                }
            }
        }
    } catch {
        print("Error: \(error.localizedDescription).")
    }
}

20:17 - Enable Fast Start Mode

// Set canStartWithMinimumPlayers to true to enable Fast Start mode
let request = GKMatchRequest()
request.minPlayers = 2
request.maxPlayers = 6
request.playerGroup = 2021

let vc = GKMatchmakerViewController(matchRequest: request)
vc.canStartWithMinimumPlayers = true
vc.delegate = self
self.present(vc, animated: true, completion: nil)

20:39 - Handle Players Who Join The Game

// Set the GKMatch delegate and present your game scene when didFindMatch is called
func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFind match: GKMatch) {
    viewController.dismiss(animated: true, completion: nil)
    let gameVC = GameSceneViewController()
    gameVC.match = match
    match.delegate = gameVC
    self.present(gameVC, animated: true, completion: nil)
}

// Add players who join later by implementing didChangeState delegate
func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) {
    if state == .connected {
        self.addPlayer(player)
    }
}

20:54 - Present GKMatchmakerViewController on The Invitee Side

// On the invitee side, present GKMatchmakerViewController with the invite
func player(_ player: GKPlayer, didAccept invite: GKInvite) {
    if let vc = GKMatchmakerViewController(invite: invite) {
        vc.matchmakerDelegate = self
        self.present(vc, animated: true, completion: nil)
    }
}