objective-c – 无法在Swift中使用NSCoder解码Int

发布时间：2020-12-14 19:54:51 所属栏目：百科来源：网络整理

导读：我正在使用 Xcode8 Beta和 Swift 3.0.我试图在NSObject上编码一个简单的对象,但我无法解码Int或NSInteger类型. (编码过程没问题) 代码 class Model : NSObject,NSCoding { var seq: NSNumber? var seq2: Int? // problem with seq2,NSInteger is not ok,eith

我正在使用 Xcode8 Beta和 Swift 3.0.我试图在NSObject上编码一个简单的对象,但我无法解码Int或NSInteger类型. (编码过程没问题)

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代码

class Model : NSObject,NSCoding {
    var seq: NSNumber?
    var seq2: Int? // problem with seq2,NSInteger is not ok,either
    var id: String?
    var value: String?

    override init() {
        super.init()
    }

    required init?(coder aDecoder: NSCoder){
        self.seq = aDecoder.decodeObject(forKey: "seq") as? NSNumber
        self.seq2 = aDecoder.decodeInteger(forKey: "seq2")
        self.id = aDecoder.decodeObject(forKey: "id") as? String
        self.value = aDecoder.decodeObject(forKey: "value") as? String
    }

    func encode(with aCoder: NSCoder){
        aCoder.encode(seq,forKey: "seq")
        aCoder.encode(seq2,forKey: "seq2")
        aCoder.encode(id,forKey: "id")
        aCoder.encode(value,forKey: "value")
    }
}

解决方法

问题是seq2不是Int,而是Int？可选的.它不能表示为Objective-C整数.

您可以使用decodeObject：

required init?(coder aDecoder: NSCoder){
    self.seq = aDecoder.decodeObject(forKey: "seq") as? NSNumber
    self.seq2 = aDecoder.decodeObject(forKey: "seq2") as? Int
    self.id = aDecoder.decodeObject(forKey: "id") as? String
    self.value = aDecoder.decodeObject(forKey: "value") as? String

    super.init()
}

或更改它,使其不是可选的：

class Model : NSObject,NSCoding {
    var seq: NSNumber?
    var seq2: Int
    var id: String?
    var value: String?

    init(seq: NSNumber,seq2: Int,id: String,value: String) {
        self.seq = seq
        self.seq2 = seq2
        self.id = id
        self.value = value

        super.init()
    }

    required init?(coder aDecoder: NSCoder) {
        self.seq = aDecoder.decodeObject(forKey: "seq") as? NSNumber
        self.seq2 = aDecoder.decodeInteger(forKey: "seq2")
        self.id = aDecoder.decodeObject(forKey: "id") as? String
        self.value = aDecoder.decodeObject(forKey: "value") as? String

        super.init()
    }

    func encode(with aCoder: NSCoder) {
        aCoder.encode(seq,forKey: "value")
    }

    override var description: String { return "<Model; seq=(seq); seq2=(seq2); id=(id); value=(value)>" }
}

（编辑：李大同）

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