fatal error: can't unsafeBitCast between types of different sizes (using gamekit)

Question

使用此处找到的 GameKit 多人游戏功能 (EasyGameCenter)：https://github.com/DaRkD0G/Easy-Game-Center-Swift

当两个玩家连接时，我在这条线上崩溃了

let playerIDs = match.players.map { [=10=] .playerID } as! [String]

在控制台中使用这个

fatal error: can't unsafeBitCast between types of different sizes

有什么想法吗？这里是完整的功能，方便参考：

 @available(iOS 8.0, *)
    private func lookupPlayers() {

        guard let match =  EGC.sharedInstance.match else {
            EGC.printLogEGC("No Match")
            return
        }

        let playerIDs = match.players.map { [=11=] .playerID } as! [String]

        /* Load an array of player */
        GKPlayer.loadPlayersForIdentifiers(playerIDs) {
            (players, error) in

            guard error == nil else {
                EGC.printLogEGC("Error retrieving player info: \(error!.localizedDescription)")
                EGC.disconnectMatch()
                return
            }

            guard let players = players else {
                EGC.printLogEGC("Error retrieving players; returned nil")
                return
            }
            if EGC.debugMode {
                for player in players {
                    EGC.printLogEGC("Found player: \(player.alias)")
                }
            }

            if let arrayPlayers = players as [GKPlayer]? { self.playersInMatch = Set(arrayPlayers) }

            GKMatchmaker.sharedMatchmaker().finishMatchmakingForMatch(match)
            (Static.delegate as? EGCDelegate)?.EGCMatchStarted?()

        }
    }

Answer 1

问题是您的 map 语句导致 Array<String?> 类型，因为 playerID 是 String?，您不能将其直接转换为 Array<String>.

如果您确定您将始终拥有一个 playerID 值，您可以更改语句

match.players.map { [=10=].playerID }

至：

match.players.map { [=11=].playerID! }

如果您不确定这一点，那么您可以使用 Array<String?> 值并进行适当的可选处理，或者通过从 map 切换到 [来删除 nil 值=22=]:

match.players.flatMap { [=12=].playerID }

fatal error: can't unsafeBitCast between types of different sizes (using gamekit)

fatal error: can't unsafeBitCast between types of different sizes (using gamekit)

gamekit

game-center

swift