ios - Swift:不符合协议(protocol) NSCoding

Question

我正在尝试在我用 swift 编写的类上使用 NSCoding 协议(protocol)，但似乎无法弄清楚为什么编译器在我实现所需方法时提示它“不符合协议(protocol) NSCoding”:

class ServerInfo: NSObject, NSCoding {

    var username = ""
    var password = ""
    var domain = ""
    var location = ""
    var serverFQDN = ""
    var serverID = ""

    override init() {

    }

    init(coder aDecoder: NSCoder!) {
        self.username = aDecoder.decodeObjectForKey("username") as NSString
        self.password = aDecoder.decodeObjectForKey("password") as NSString
        self.domain = aDecoder.decodeObjectForKey("domain") as NSString
        self.location = aDecoder.decodeObjectForKey("location") as NSString
        self.serverFQDN = aDecoder.decodeObjectForKey("serverFQDN") as NSString
        self.serverID = aDecoder.decodeObjectForKey("serverID") as NSString
    }


    func encodeWithCoder(_aCoder: NSCoder!) {
        _aCoder.encodeObject(self.username, forKey: "username")
        _aCoder.encodeObject(self.password, forKey: "password")
        _aCoder.encodeObject(self.domain, forKey: "domain")
        _aCoder.encodeObject(self.location, forKey: "location")
        _aCoder.encodeObject(self.serverFQDN, forKey: "serverFQDN")
        _aCoder.encodeObject(self.serverID, forKey: "serverID")
    }

}

这是一个错误还是我只是遗漏了什么？

Answer 1

正如您在报告导航器中的详细编译器消息中所见，您的方法未正确声明:

error: type 'ServerInfo' does not conform to protocol 'NSCoding'class ServerInfo: NSObject, NSCoding {^Foundation.NSCoding:2:32: note: protocol requires function 'encodeWithCoder' with type '(NSCoder) -> Void'  @objc(encodeWithCoder:) func encodeWithCoder(aCoder: NSCoder)                               ^note: candidate has non-matching type '(NSCoder!) -> ()'    func encodeWithCoder(_aCoder: NSCoder!) {         ^Foundation.NSCoding:3:25: note: protocol requires initializer 'init(coder:)' with type '(coder: NSCoder)'  @objc(initWithCoder:) init(coder aDecoder: NSCoder)                        ^note: candidate has non-matching type '(coder: NSCoder!)'    init(coder aDecoder: NSCoder!) {

(This may have changed between the beta releases.)In addition, the initWithCoder method has to be marked as required:

required init(coder aDecoder: NSCoder) {   }

func encodeWithCoder(_aCoder: NSCoder) {   }

在 Swift 3 中，所需的方法是

required init(coder aDecoder: NSCoder) {   }

func encode(with aCoder: NSCoder) {   }