致命错误:不能在不同大小的类型之间使用unsafeBitCast(使用游戏包) [英] fatal error: can't unsafeBitCast between types of different sizes (using gamekit)

问题描述

在此处使用GameKit多人游戏功能(EasyGameCenter): https://github.com/DaRkD0G/简易游戏中心-Swift

Using GameKit Multiplayer feature (EasyGameCenter) found here: https://github.com/DaRkD0G/Easy-Game-Center-Swift

在连接两个玩家时，我在这条线上撞车了

Upon two players connecting I get a crash on this line

let playerIDs = match.players.map { $0 .playerID } as! [String]

在控制台中使用此

严重错误:不能在不同大小的类型之间使用unsafeBitCast

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

有什么想法吗?以下是功能齐全，供您参考:

Any ideas? Here is full function for easy reference:

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

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

        let playerIDs = match.players.map { $0 .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?()

        }
    }

推荐答案

问题是您的map语句生成的类型为Array<String?>，因为playerID是String?，您不能直接投射到Array<String>.

The problem is that your map statement is resulting in a type of Array<String?> because playerID is a String?, which you can't cast directly to Array<String>.

如果确定您将始终具有playerID值，则可以更改该语句

If you're certain you will always have a playerID value, you could change the statement

match.players.map { $0.playerID }

收件人:

match.players.map { $0.playerID! }

如果不确定，可以使用Array<String?>值进行适当的可选处理，也可以通过从map切换到flatMap去除nil值:

If you're not certain of that, then you can either use the Array<String?> value with appropriate optional handling or strip out the nil values by switching from map to flatMap:

match.players.flatMap { $0.playerID }

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