【发布时间】：2015-07-28 00:46:52
【问题描述】：
我尝试在 Xcode 6.3.1 中使用 Swift 将元素插入到 Core Data 中，但出现错误。我采用了几个 Stackoverflow 答案（列在底部）中的解决方案，但没有一个有助于解决问题。
我创建了另一个应用程序来简化代码和问题，希望它能为遇到此问题的其他人提供更大的好处。
错误： CoreData：警告：无法为实体“Test”加载名为“Scratch.Test”的类。找不到类，改用默认的 NSManagedObject。
代码： （更新：修复前）
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(true)
let saveData = saveDataLabel.text
println(saveData)
let appDel = UIApplication.sharedApplication().delegate as! AppDelegate
let context = appDel.managedObjectContext!
let en = "Test"
let entity = NSEntityDescription.entityForName(en, inManagedObjectContext: context)
let test = Test(entity: entity!, insertIntoManagedObjectContext: context)
test.saveMe = saveData!
var error: NSError?
if !context.save(&error){
println("Could not save \(error), \(error?.userInfo)")
}
// let fetchRequest = NSFetchRequest(entityName: "Test")
// let fetchedEntities = appDel.managedObjectContext!.executeFetchRequest(fetchRequest, error: nil) as! [Test]
//
// if(fetchedEntities.count == 0){
// NSLog("I'm empty")
// } else {
// NSLog("\(fetchedEntities[0].saveMe)")
// }
}
数据模型 抱歉，我是新来的，不允许发布图片
应用名称：Scratch
- Scratch.xcdatamodeld
- - 测试（使用 Class = Scratch.Test）
- - - saveMe（作为字符串）
Test.swift 中的代码
import Foundation
import CoreData
@objc(Test)
class Test: NSManagedObject {
@NSManaged var saveMe: String
}
AppDelegate.swift 中的代码
import UIKit
import CoreData
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
return true
}
// MARK: - Core Data stack
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "self.com.AG.TaskIt" in the application's documents Application Support directory.
let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
return urls[urls.count-1] as! NSURL
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = NSBundle.mainBundle().URLForResource("Scratch", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Scratch.sqlite")
var error: NSError? = nil
var failureReason = "There was an error creating or loading the application's saved data."
if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
coordinator = nil
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
dict[NSLocalizedFailureReasonErrorKey] = failureReason
dict[NSUnderlyingErrorKey] = error
error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext? = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
if coordinator == nil {
return nil
}
var managedObjectContext = NSManagedObjectContext()
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Core Data Saving support
func saveContext () {
if let moc = self.managedObjectContext {
var error: NSError? = nil
if moc.hasChanges && !moc.save(&error) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog("Unresolved error \(error), \(error!.userInfo)")
abort()
}
}
}
}
我找不到任何可以让我克服这个错误的东西。以下是我发现的一些无效的解决方案：
【问题讨论】：
-
显示您的抓取代码。
-
您好 Mundi，我已更新 代码 部分以显示我在 ViewController 中的 viewDidLoad() 的所有代码。我目前没有使用 Fetch 代码。这是个问题吗？