Question

尝试将字符串添加到Core Data时，我收到标题错误。这是我的代码：

 func save(name: String) {
        let model = CoreDataModel(modelName: modelName, modelBundle: modelBundle!, storeType: .SQLite(DocumentsDirectoryURL()))
        let factory = CoreDataFactory(model: model)

        let context = factory.createContext()
        let entity = NSEntityDescription.entityForName("Transaction", inManagedObjectContext: context)
        let transaction = NSManagedObject(entity: entity!, insertIntoManagedObjectContext: context)

        transaction.setValue(name, forKey: "name")

        do {
            try context.save()
            transactions.append(transaction)
        }catch let error as NSError {
            print(error)
        }
    }


func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
   let cell = tableView.dequeueReusableCellWithIdentifier("Cell")

   let transaction = transactions[indexPath.row]
   print(transaction)
   cell!.textLabel!.text = transaction.valueForKey("name") as? String 

   return cell!
}

错误在这一行：

cell!.textLabel!.text = transaction.valueForKey("name") as? String

这是完整的错误描述：

<NSManagedObject: 0x7f9d5c216a90> (entity: <null>; id: 0xd000000000040000 <x-coredata://442A125F-AB41-4CA3-AAA5-A5C59840D5EE/Transaction/p1> ; data: <fault>)
2016-04-13 19:25:29.207 Project1[22981:2242560] *** -[NSEntityDescription _entityClass]: message sent to deallocated instance 0x7f9d5c2089e0

任何人都知道我为什么会这样做？

Answer 1

似乎问题是我在本地创建NSManagedObjectContext以保存（），我必须将前3行移动到ViewDidLoad，并将context声明为类成员。

This线程帮助我解决了问题。

消息发送到解除分配的实例Core Data

1 个答案: