Question

我有一个Swift 3 iOS应用程序，我希望能够共享我存储在Core Data中的实体。我所做的是在NSManagedObject类中实现NSCoding：

导入基金会导入CoreData 导入UIKit

public class Event: NSManagedObject, NSCoding {

    // MARK: NSCoding

    override init(entity: NSEntityDescription, insertInto context: NSManagedObjectContext?) {
        super.init(entity: entity, insertInto: context)
    }

    required public init(coder aDecoder: NSCoder) {
        let ctx = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
        let entity = NSEntityDescription.entity(forEntityName: "Group", in: ctx)!

        // Note: pass `nil` to `insertIntoManagedObjectContext`
        super.init(entity: entity, insertInto: nil)

        for attribute:String in self.entity.attributesByName.keys{
            self.setValue([aDecoder.decodeObject(forKey: attribute)], forKey: attribute)
        }
    }

    public func encode(with aCoder: NSCoder){
        for attribute:String in self.entity.attributesByName.keys{
            aCoder.encode(self.value(forKey: attribute), forKey: attribute)
        }
    }

}

然后我尝试使用以下方法序列化对象：

    NSKeyedArchiver.archiveRootObject(selectedGroup, toFile: file)

但是当它被执行时，它失败了：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[_SwiftValue encodeWithCoder:]: unrecognized selector sent to instance

所以，即使我已经实现了NSCoding协议，由于某种原因，NSCoding协议似乎并不坚持。知道我做错了吗？

带有NSCoding的NSManagedObject无法正常工作

0 个答案: