SWIFT CoreData NSManagedObject

问题

I have a Custom NSManagedObject (in Swift) and looks like this

import UIKit
import CoreData

@objc(Item)
class Item: NSManagedObject {

@NSManaged var title:String

func entityName() -> String{
    println("Entity Name")
    let item = "Item"
    return item
}

func insertItemWithTitle (title: String? , managedObjectContext:NSManagedObjectContext) -> Item{
    println(title)
    let item = NSEntityDescription.insertNewObjectForEntityForName(entityName(), inManagedObjectContext: managedObjectContext) as Item
    if title {
        item.title = title!
    }
    return item
}

}

What is The proper way to Initialize something like this and use it

回答1:

Instantiation (e.g. init) is taken care of by Core Data, so a class factory method is recommended for what you want to do. For example:

@objc(Item)
class Item: NSManagedObject {

    @NSManaged var title:String

    class func entityName() -> String {
        return "Item"
    }

    class func insertItemWithTitle(title: String, managedObjectContext:NSManagedObjectContext) -> Item {
        let item = NSEntityDescription.insertNewObjectForEntityForName(Item.entityName(), inManagedObjectContext: managedObjectContext) as! Item
        item.title = title
        return item
    }
}

You might also make parameter title NOT optional since the managed attribute title is required. Or, you can make title optional, but make sure your model is updated to reflect this change.

回答2:

Hmmm. How about

var item = Item.insertItemWithTitle(title:"Item Title", context)
item.entityName()

来源：https://stackoverflow.com/questions/24792372/swift-coredata-nsmanagedobject

标签

ios

core-data

nsmanagedobject