Swift - Core Data & NSCoding : Failed to call designated initializer

Question

I am struggling with the following case in Swift :

I have a NSManaged class called Event :

import UIKit
import Foundation
import CoreData

class Event: NSManagedObject, NSCoding {

@NSManaged var eventArchived: Bool
@NSManaged var eventCCRecipientAddress: String?
@NSManaged var eventCCRecipientName: String?
@NSManaged var eventEndDate: String?
@NSManaged var eventEndRSVPDateTime: String?
@NSManaged var eventHappeningId: String?
@NSManaged var eventName: String?
@NSManaged var eventResourcesFolderName: String?
@NSManaged var eventStartDate: String?
@NSManaged var eventId: String?
@NSManaged var eventHappening: Happening

override init(entity: NSEntityDescription, insertIntoManagedObjectContext context: NSManagedObjectContext?) {
    super.init(entity: entity, insertIntoManagedObjectContext: context)
}

// MARK: NSCoding protocol conformance
required init(coder aDecoder: NSCoder) {

    let context = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext!
    let entity = NSEntityDescription.entityForName("Event", inManagedObjectContext: context)!

    // Note: pass `nil` to `insertIntoManagedObjectContext`
    super.init(entity: entity, insertIntoManagedObjectContext: nil)

    if let eventArchived = aDecoder.decodeObjectForKey("eventArchived") as? Bool {
        self.eventArchived = eventArchived
    }
    if let eventCCRecipientAddress = aDecoder.decodeObjectForKey("eventCCRecipientAddress") as? String {
        self.eventCCRecipientAddress = eventCCRecipientAddress
    }
    if let eventCCRecipientName = aDecoder.decodeObjectForKey("eventCCRecipientName") as? String {
        self.eventCCRecipientName = eventCCRecipientName
    }
    if let eventEndDate = aDecoder.decodeObjectForKey("eventEndDate") as? String {
        self.eventEndDate = eventEndDate
    }
    if let eventEndRSVPDateTime = aDecoder.decodeObjectForKey("eventEndRSVPDateTime") as? String {
        self.eventEndRSVPDateTime = eventEndRSVPDateTime
    }
    if let eventHappeningId = aDecoder.decodeObjectForKey("eventHappeningId") as? String {
        self.eventHappeningId = eventHappeningId
    }
    if let eventName = aDecoder.decodeObjectForKey("eventName") as? String {
        self.eventName = eventName
    }
    if let eventResourcesFolderName = aDecoder.decodeObjectForKey("eventResourcesFolderName") as? String {
        self.eventResourcesFolderName = eventResourcesFolderName
    }
    if let eventStartDate = aDecoder.decodeObjectForKey("eventStartDate") as? String {
        self.eventStartDate = eventStartDate
    }
    if let eventId = aDecoder.decodeObjectForKey("eventId") as? String {
        self.eventId = eventId
    }
}

func encodeWithCoder(aCoder: NSCoder) {

    aCoder.encodeObject(eventArchived, forKey: "eventArchived")

    if let eventCCRecipientAddress = self.eventCCRecipientAddress {
        aCoder.encodeObject(eventCCRecipientAddress, forKey: "eventCCRecipientAddress")
    }
    if let eventCCRecipientName = self.eventCCRecipientName {
        aCoder.encodeObject(eventCCRecipientName, forKey: "eventCCRecipientName")
    }
    if let eventEndDate = self.eventEndDate {
        aCoder.encodeObject(eventEndDate, forKey: "eventEndDate")
    }
    if let eventEndRSVPDateTime = self.eventEndRSVPDateTime {
        aCoder.encodeObject(eventEndRSVPDateTime, forKey: "eventEndRSVPDateTime")
    }
    if let eventCCRecipientAddress = self.eventCCRecipientAddress {
        aCoder.encodeObject(eventCCRecipientAddress, forKey: "eventCCRecipientAddress")
    }
    if let eventHappeningId = self.eventHappeningId {
        aCoder.encodeObject(eventHappeningId, forKey: "eventHappeningId")
    }
    if let eventName = self.eventName {
        aCoder.encodeObject(eventName, forKey: "eventName")
    }
    if let eventResourcesFolderName = self.eventResourcesFolderName {
        aCoder.encodeObject(eventResourcesFolderName, forKey: "eventResourcesFolderName")
    }
    if let eventStartDate = self.eventStartDate {
        aCoder.encodeObject(eventStartDate, forKey: "eventStartDate")
    }
    if let eventId = self.eventId {
        aCoder.encodeObject(eventId, forKey: "eventId")
    }

    aCoder.encodeObject(eventHappening, forKey: "eventHappening")
}
}

The class used to be "simple" with only the NSManaged variables until I've been asked to implement the NSCoding protocol. I use NSCoding because I need to be aware of the Current Event anywhere in my app, including offline mode.

When I try to use my Event Class, I keep having the following error :

CoreData: error: Failed to call designated initializer on NSManagedObject class 'AccueilInviteVIP.Event'

This is how I try to access my class :

var currentEvent = Event()

Then in viewDidLoad Method :

    // currentEvent
    currentEvent = NSEntityDescription.insertNewObjectForEntityForName("Event", inManagedObjectContext: self.managedObjectContext!) as! Event

And it crashes on this line.

The error should be pretty clear, it seems that my init methods are incorrect but I cannot get it working, as I am new to Swift and can't find any example close to this.

Any help would be great !

Thank you,

Hugo

score 0 · Accepted Answer · answered Jul 20 '15 at 09:37

Looks like over-engineering and way too much code to me.

Why not just store the eventId and retrieve the object from Core Data? To also archive it sees really messy and redundant.

// store
NSUserDefaults.standardUserDefaults().setObject(event.eventId forKey:"mainEventID")

// retrieve
let eventId = NSUserDefaults.standardUserDefaults().stringForKey("mainEventId")!
let request = NSFetchRequest(entityName: "Event")
request.predicate = NSPredicate(format: "eventId = %@", eventId)
let event = (context.executeFetchRequest(request, error:nil) as [Event]).first!

You will have to do some more error and nil checking but you get the idea.

Swift - Core Data & NSCoding : Failed to call designated initializer

1 Answers1