ios - 如何在 Swift 中归档和取消归档自定义对象？或者如何在 Swift 中将自定义对象保存到 NSUserDefaults？

Question

我有课

class Player {

    var name = ""

    func encodeWithCoder(encoder: NSCoder) {
        encoder.encodeObject(name)
    }

    func initWithCoder(decoder: NSCoder) -> Player {
        self.name = decoder.decodeObjectForKey("name") as String
        return self
    }

    init(coder aDecoder: NSCoder!) {
        self.name = aDecoder.decodeObjectForKey("name") as String
    }

    init(name: String) {
        self.name = name
    }
}

我想序列化它并保存到用户默认值。

首先，我不确定如何正确编写编码器和解码器。所以对于 init 我写了两个方法。

当我尝试执行这段代码时:

func saveUserData() {
    let player1 = Player(name: "player1")
    let myEncodedObject = NSKeyedArchiver.archivedDataWithRootObject(player1)
    NSUserDefaults.standardUserDefaults().setObject(myEncodedObject, forKey: "player")
}

应用程序崩溃，我收到此消息:

*** NSForwarding: warning: object 0xebf0000 of class '_TtC6GameOn6Player' does not implement methodSignatureForSelector: -- trouble ahead

我做错了什么？

Answer 1

在 Swift 4 中你不再需要 NSCoding 了!有一个名为 Codable 的新协议(protocol)!

class Player: Codable {

    var name = ""

    init(name: String) {
        self.name = name
    }
}

Codable 还支持枚举和结构，因此您可以根据需要将播放器类重写为结构!

struct Player: Codable {
    let name: String
}

将您的播放器保存在 Userdefaults 中:

let player = Player(name: "PlayerOne")
try? UserDefaults.standard.set(PropertyListEncoder().encode(player), forKey: "player")

注意:PropertyListEncoder()是框架Foundation中的一个类

检索:

let encoded = UserDefault.standard.object(forKey: "player") as! Data
let storedPlayer = try! PropertyListDecoder().decode(Player.self, from: encoded)

有关详细信息，请阅读 https://developer.apple.com/documentation/swift/codable