设置异常中的Swift保存cutom类：'；NSInvalidArgumentException'；，原因：'；***-仅为抽象类定义了长度

您好，我尝试使用NSUserDefaults存储自定义对象。我用了这个有用的帖子

但是当我尝试它时，我得到了以下异常

2015-05-12 11:05:14.994 KirchnerTime[4424:75095]*由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：'*-仅为抽象类定义了长度。定义-[项目长度]！'

这是应该存储的对象

 public func saveSettings()
{
    let settings = NSUserDefaults.standardUserDefaults()
    settings.setValue(self._cardNumber, forKeyPath: cardNumberKey)

    settings.setObject(NSKeyedArchiver.archivedDataWithRootObject(ProjectJobEntity(barCode: "Test")), forKey: "Project")
}

我就是这样尝试的。

我也有同样的例外

我使用NSObject作为父类

在代码下使用

    public class ProjectJobEntity: NSObject
    {
        private let _barCode: String
        private var _projectNumber: String
        private var _projectDescription: String
        private var _jobDescription: String

        public var BarCode: String
            {
            get { return self._barCode }
        }

        public var ProjectNumber: String
            {
            get { return self._projectNumber }
            set { self._projectNumber = newValue }
        }

        public var ProjectDescription: String
            {
            get { return self._projectDescription }
            set { self._projectDescription = newValue }
        }

        public var JobDescription: String
            {
            get { return self._jobDescription }
            set { self._jobDescription = newValue }
        }

        public init(barCode: String, projectNumber: String, projectDescription: String, jobDescription: String)
        {
            self._barCode = barCode
            self._projectNumber = projectNumber
            self._projectDescription = projectDescription
            self._jobDescription = jobDescription

            super.init()
        }


        public init(barCode: String)
        {
            self._barCode = barCode
            self._projectNumber = ""
            self._projectDescription = ""
            self._jobDescription = ""

            super.init()
        }

        public func encodeWithCoder(aCoder: NSCoder)
        {
            aCoder.encodeObject(self._barCode, forKey: "barCode")
            aCoder.encodeObject(self._projectNumber, forKey: "projectNumber")
            aCoder.encodeObject(self._projectDescription, forKey: "projectDescription")
            aCoder.encodeObject(self._jobDescription, forKey: "jobDescription")
        }

        public func initWithCoder(aDecoder: NSCoder) -> ProjectJobEntity
        {
            let barCode = aDecoder.decodeObjectForKey("barCode") as! String
            let projectNumber = aDecoder.decodeObjectForKey("projectNumber") as! String
            let projectDescription = aDecoder.decodeObjectForKey("projectDescription") as! String
            let jobDescription = aDecoder.decodeObjectForKey("jobDescription") as! String

            return ProjectJobEntity(barCode: barCode, projectNumber: projectNumber, projectDescription: projectDescription, jobDescription: jobDescription)
        }
    }

    public class ProjectJobEntity: NSObject
    {
        private let _barCode: String
        private var _projectNumber: String
        private var _projectDescription: String
        private var _jobDescription: String

        public var BarCode: String
            {
            get { return self._barCode }
        }

        public var ProjectNumber: String
            {
            get { return self._projectNumber }
            set { self._projectNumber = newValue }
        }

        public var ProjectDescription: String
            {
            get { return self._projectDescription }
            set { self._projectDescription = newValue }
        }

        public var JobDescription: String
            {
            get { return self._jobDescription }
            set { self._jobDescription = newValue }
        }

        public init(barCode: String, projectNumber: String, projectDescription: String, jobDescription: String)
        {
            self._barCode = barCode
            self._projectNumber = projectNumber
            self._projectDescription = projectDescription
            self._jobDescription = jobDescription

            super.init()
        }


        public init(barCode: String)
        {
            self._barCode = barCode
            self._projectNumber = ""
            self._projectDescription = ""
            self._jobDescription = ""

            super.init()
        }

        public func encodeWithCoder(aCoder: NSCoder)
        {
            aCoder.encodeObject(self._barCode, forKey: "barCode")
            aCoder.encodeObject(self._projectNumber, forKey: "projectNumber")
            aCoder.encodeObject(self._projectDescription, forKey: "projectDescription")
            aCoder.encodeObject(self._jobDescription, forKey: "jobDescription")
        }

        public func initWithCoder(aDecoder: NSCoder) -> ProjectJobEntity
        {
            let barCode = aDecoder.decodeObjectForKey("barCode") as! String
            let projectNumber = aDecoder.decodeObjectForKey("projectNumber") as! String
            let projectDescription = aDecoder.decodeObjectForKey("projectDescription") as! String
            let jobDescription = aDecoder.decodeObjectForKey("jobDescription") as! String

            return ProjectJobEntity(barCode: barCode, projectNumber: projectNumber, projectDescription: projectDescription, jobDescription: jobDescription)
        }
    }