Swift：将核心数据与基于选项卡式的应用程序一起使用 错误：'Cannot create an NSPersistentStoreCoordinator with a nil model'

Question

我试图在一个基于选项卡的应用程序中使用核心数据。但是当我试图保存一些东西时，它会给出以下错误:

'不能用nil模型创建NSPersistentStoreCoordinator '

这是我的app委托:

import UIKit
import CoreData
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?

func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
    // Override point for customization after application launch.
    return true
}
func applicationWillResignActive(application: UIApplication!) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}
func applicationDidEnterBackground(application: UIApplication!) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(application: UIApplication!) {
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(application: UIApplication!) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(application: UIApplication!) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
// 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 "Coders.test" 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("test", 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("test.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.
        let dict = NSMutableDictionary()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError.errorWithDomain("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 {
        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()
        }
    }
}

我保存数据的功能:

func calculate(maand: UITextField!, urenGewerkt: UITextField!, uurloon: UITextField!) {
    NSLog("(maand.text)")
    let appDel: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let context: NSManagedObjectContext = appDel.managedObjectContext!
    let en = NSEntityDescription.entityForName("Loon", inManagedObjectContext: context)
    //Create instance of pur data model and initialize
    var newItem = dataHandlingClass(entity: en, insertIntoManagedObjectContext: context)
    if maand.text.isEmpty && urenGewerkt.text.isEmpty && uurloon.text.isEmpty {
        NSLog("Empty")
    } else {
        newItem.maand = maand!.text
        newItem.uurGewerkert = urenGewerkt!.text
        newItem.uurLoon = uurloon!.text
        var error: NSError?
        context.save(&error)
    }

}

Datahandling类:

import UIKit
import CoreData
class dataHandlingClass : NSManagedObject {
    @NSManaged var maand: String!
    @NSManaged var uurLoon: String!
    @NSManaged var uurGewerkert: String!
}

有谁知道我如何修复这个错误吗?

我看到了一些相关的问题，但是我没有得到我需要的答案。

Answer 1

当您使用.xcdatamodel而不是.scdatamodeld时，您应该以以下方式构建模型包URL:

let modelURL = NSBundle.mainBundle().URLForResource("test", withExtension: "mom") // not momd!