Create nsmanagedobject without saving [@Example]

Question

I want to create a NSManagedObject but not save immediately.

Where can I find an example of creating a temporary NSmanagedObject?

Answer 1

This was tested On IOS7, IOS8.

Create tmp NSManagedContext : To make sure that your NSManagedObject will not be nil when your context will be dealloc create a temporary NSManagedContext in your Application delegate.

in file AppDelegate.swift

import UIKit
import CoreData

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    private(set) var tmpContext : NSManagedObjectContext = NSManagedObjectContext()

    ....

}

Create a NSManagedObject : Call in your customfile.swift tmp and the main context. The main context will be use to reach your model at the instance of your NSManagedObject.

    // CONTEXT
    let tmpContext     = (UIApplication.sharedApplication().delegate as AppDelegate).tmpContext
    let managedContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext!

    // ENTITY
    let entity         = NSEntityDescription.entityForName("MY_ENTITY_NAME", inManagedObjectContext: managedContext)
    let obj            = NSManagedObject(entity: entity!, insertIntoManagedObjectContext: tmpContext)

Save Your NSManagedObject : unfortunately you cannot save your object by passing the main context. To avoid, you will need to copy all your NSManagedObject

var error : NSError?

// CREATE YOUR NSManagedObject
    let managedContext     = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext!
    let entity             = NSEntityDescription.entityForName("MY_ENTITY_NAME", inManagedObjectContext: managedContext)
    let newObj             = NSManagedObject(entity: entity!, insertIntoManagedObjectContext: managedContext)


// COLLECT ALL VALUE SET OF YOUR OBJ            
    let keysObj            = (obj.entity.attributesByName as NSDictionary).allKeys
    let dictObj            = track.dictionaryWithValuesForKeys(keysObj)


 newObj.setValuesForKeysWithDictionary(dictObj)

 // SAVE ALL

 managedContext.processPendingChanges()
 managedContext.insertObject(newObj)
 managedContext.save(&error) // dont forget to check