无法加载指定的初始化程序核心数据

Question

I have been struggling with creating a class to manage Core Data. I cannot seem to get passed the "Failed to call designated initializer on NSManaged Object"

How can I fix this?

This is my created class to manage the data :

import Foundation
import CoreData
import UIKit

class Hours: NSManagedObject {

    @NSManaged var date: NSDate
    @NSManaged var startTime: NSDate
    @NSManaged var endTime: NSDate
    @NSManaged var totalTime: Double

    override init(entity: NSEntityDescription, insertIntoManagedObjectContext context: NSManagedObjectContext?){
        let entity = NSEntityDescription.entityForName("Hours", inManagedObjectContext: context!)
        super.init(entity: entity!, insertIntoManagedObjectContext: context)
    }
    let appDel:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    var context:NSManagedObjectContext {
        get{
            return appDel.managedObjectContext
        }
    }



    class func insertTimes(date: NSDate, startTime:NSDate, endTime:NSDate,totalTime:Double) -> Hours{
        let hour:Hours = Hours()
        let newDate:Hours = NSEntityDescription.insertNewObjectForEntityForName("Hours", inManagedObjectContext: hour.context) as! Hours
        print("date = \(date), start = \(startTime), end = \(endTime), total = \(totalTime)")
        newDate.date = date
        newDate.startTime = startTime
        newDate.endTime = endTime
        newDate.totalTime = totalTime
/*
        newDate.setValue(date, forKey: "date")
        newDate.setValue(startTime, forKey: "startTime")
        newDate.setValue(endTime, forKey:"endTime")
        newDate.setValue(totalTime, forKey: "totalTime")
*/
        do{
            try hour.context.save()
            print("Succesfully saved")
        }catch{
        print("Unresolved save error")
        }

        return newDate


    }

    func returnDate(){
        //Does not work YET
        let request = NSFetchRequest(entityName: "Hours")
        //request.returnsObjectsAsFaults = false
        do{
            let results = try context.executeFetchRequest(request)
            print(results)
        }catch{
            print("Unresolved fetch error")
        }
    }
}

I try to call the method insertTimes with the following line of code, after I press a button.

 @IBAction func saveData(sender: AnyObject) {
    let inserted:Hours = Hours.insertTimes(date, startTime: startEndDate.startTime, endTime: startEndDate.endTime, totalTime: timeInterval)

}

Please note that all my variables are of the right types.

Source can be found on: https://github.com/bbriann123/PayDay/blob/master/Hours.swift

Answer 1

Look a these:

• In AppDelegate you use "Loon Calculator" instead of "DayDataModel": https://github.com/bbriann123/PayDay/blob/master/Loon%20Calculator/AppDelegate.swift#L55 (the data model file name is clearly "DayDataModel": https://github.com/bbriann123/PayDay/tree/master/Loon%20Calculator/DayDataModel.xcdatamodeld/DayDataModel.xcdatamodel )

• In the data model you don't specify "Hours" as the custom class of the "Hours" entity (look in the Core Data inspector)

• Also, it's weird how you reach to the NSManagedObjectContext : https://github.com/bbriann123/PayDay/blob/master/Hours.swift#L25-L30

Maybe you need a better Core Data book (or whatever you're using to learn)?