How to include NSPersistentContainer in AppDelegate

Question

I'm receiving an error:

AppDelegate has no member persistentContainer

import UIKit
import CoreData

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let context = appDelegate.persistentContainer.viewContext // Error: value of type 'AppDelegate' has no member 'persistentContainer'
    }

}

In AppDelegate.swift file, NSPersistentStoreCoordinator is defined as default.

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
    var failureReason = "There was an error creating or loading the application's saved data."
    do {
        try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
    }
    catch {
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error as NSError
        let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
        abort()
    }
    return coordinator
}()

Solution

You should firstly import CoreData framework and then write this code in AppDelegate.swift:

lazy var persistentContainer: NSPersistentContainer = {

    let container = NSPersistentContainer(name: "Your Model File Name")
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error {

            fatalError("Unresolved error, \((error as NSError).userInfo)")
        }
    })
    return container
}()

And then you should write this:

 let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

Comments

[Karthikeyan Sk]

i have already imported CoreData framework. now tried writing your code too . it says "use of undeclared type 'NSPersitentContainer'. Even in AppDelegate.swift file, the default class method 'NSPersistentStoreCoordinator' is shown instead 'NSPersistenContainer'.

[Pragnesh Vitthani]

Pls, write above persistentContainer class method in your AppDelegate...

[Karthikeyan Sk]

i did. it reports ' use of undeclared type NSPersistentContainer '

[Pragnesh Vitthani]

but in your question you declare persistentStoreCoordinator and in viewDidLoad() you use persistentContainer.

[Karthikeyan Sk]

Thanks i got it @pragnesh Vitthani