managedObjectContext returns nil

Question

I have created a helper class that only contains methods for retrieving data from Core Data and Parse, DataService.swift

Within that class, I have (amongst more of it) the following code:

func getUserStoreItems(itemSkuArray: [String]) {
        (...)


        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let managedContext = appDelegate.managedObjectContext

        let fetchRequest = NSFetchRequest(entityName: "Book")

        do {
            let results = try managedContext.executeFetchRequest(fetchRequest)
            let bookListNSManagedObject = results as! [NSManagedObject]
            for bookNSManagedObject in bookListNSManagedObject {
                print("Here is the Core Data \(bookNSManagedObject)")
            }
        } catch let error as NSError {
            print("Could not fetch \(error), \(error.userInfo)")
        }

    }

However, this throws a

fatal error: unexpectedly found nil while unwrapping an Optional value

on

let managedContext = appDelegate.managedObjectcontext

Here is managedObjectContext declaration:

lazy var managedObjectContext: NSManagedObjectContext = {
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
    let coordinator = self.persistentStoreCoordinator
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
}()

Any ideas?

Answer 1

delegate is an optional variable. I expect you just didn't set a delegate.

unowned(unsafe) var delegate: UIApplicationDelegate?

Try to check the delegate before use:

if let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate {
     // use appDelegate
}