Ios 尝试保存核心数据对象时出错

我一直在尝试建立一个简单的应用程序，它允许用户用价格和找到价格的商店来更新食品。我所知道的主要问题是试图将Swift与Objective-C融为一体，尽管苹果公司还没有为Swift解决问题，而且它一直在变化

无论如何，我已经设置了我的

允许TableViewController

，如下所示

class AllowedTableViewController: UITableViewController {

    var myAllowedList : Array<AnyObject> = []

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewDidAppear(animated: Bool) {

        let appDel: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        let context: NSManagedObjectContext = appDel.managedObjectContext!
        let freq = NSFetchRequest(entityName: "FoodAllowed")

        myAllowedList = context.executeFetchRequest(freq, error: nil)!
        tableView.reloadData()
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if segue.identifier == "update" {

            var indexPath: NSIndexPath = self.tableView.indexPathForSelectedRow()!
            var selectedItem: NSManagedObject = myAllowedList[indexPath.row] as NSManagedObject
            let IVC: AllowedViewController = segue.destinationViewController as AllowedViewController

            IVC.name = selectedItem.valueForKey("name")as String
            IVC.store = selectedItem.valueForKey("store")as String
            IVC.price = selectedItem.valueForKey("price")as String
            IVC.existingItem = selectedItem
            }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        // #warning Potentially incomplete method implementation.
        // Return the number of sections.
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete method implementation.
        // Return the number of rows in the section.
        return myAllowedList.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        //Configure the Cell

        let CellID: NSString = "Allowed"

        var cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(CellID) as UITableViewCell


        var data: NSManagedObject = myAllowedList[indexPath.row] as NSManagedObject
            cell.textLabel.text = (data.valueForKeyPath("name")as String)

        var pri = data.valueForKeyPath("price")as String
        var str = data.valueForKeyPath("store")as String
        cell.detailTextLabel?.text = "\(pri) name/s - \(str)"
        return cell
    }

    //Override to support conditional editing of the table view
    override func tableView(tableView: UITableView?, canEditRowAtIndexPath indexPath: NSIndexPath?) -> Bool {
        //Return NO if you do not want the specified item to be editable
        return true
    }

    //Override to support editing the table view
    override func tableView(tableView: UITableView?, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath?) {

        let appDel: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
        let context: NSManagedObjectContext = appDel.managedObjectContext!

        if editingStyle == UITableViewCellEditingStyle.Delete {

            if let tv = tableView {
            context.deleteObject(myAllowedList[indexPath!.row] as NSManagedObject)
            myAllowedList.removeAtIndex(indexPath!.row)
            tv.deleteRowsAtIndexPaths([indexPath!.row], withRowAnimation: UITableViewRowAnimation.Fade)
            }

            var error: NSError? = nil
            if !context.save(&error) {
                abort()
            }
        }       
    }
}

我的

NSManaged

数据模型是

{

@objc(DataModel)
class DataModel: NSManagedObject {

    //properties feeding the attributes in our entity
    //must match the entity attributes

    @NSManaged var name: [String]
    @NSManaged var store: [String]
    @NSManaged var price: [String]

}

}

当我在模拟器中运行应用程序时，我得到以下错误

'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "name"; desired type = NSString; given type = Swift._NSSwiftArrayImpl; value = (Apples).'

---

我做错了什么？

错误消息表明“name”、“store”和“price”是字符串属性 但您已将其定义为

[String]

，即数组 弦乐。应该是

@objc(DataModel)
class DataModel: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var store: String
    @NSManaged var price: String

}

因此

newItem.name = textFieldname.text // not: [textFieldname.text]
// ...

更好的是，让Xcode生成托管对象子类

---

（编辑器->在Xcode菜单中创建NSManagedObject子类…。

使用Swift的核心数据是否确保非可选始终合适？当然，声明为“可选”的核心数据属性应该有一个Swift可选类型aka“？”。“那”呢其他类型是否需要？（由于awakeFromNIB进程的缘故，它是针对IBOutlets的）@GoZoner：不幸的是，Xcode没有（仍然）为可选属性生成正确的代码，您必须添加！或手动。比较一下。非常感谢你的工作！复习的时候一定错过了！

newItem.name = textFieldname.text // not: [textFieldname.text]
// ...