CODEWITHSUNDEEP
iosswift
Declan McKenna
Declan McKenna

Reputation: 4910

Why are there errors in the generated AppDelegate file?

The AppDelegate xcode generates when I create a new project has errors within it which I'm struggling to debug as I'm new to swift. Why are generated files returning errors and how can I prevent this when creating new swift projects?

Error 1

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("Swift_Conversion.sqlite")
    var error: NSError? = nil
    var failureReason = "There was an error creating or loading the application's saved data."
    if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil, error: &error) == nil {
        coordinator = nil
        //ERROR: EXTRA ARGUMENT 'ERROR' IN CALL
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        NSLog("Unresolved error \(error), \(error!.userInfo)")
        abort()
    }

    return coordinator
}()

Error 2

func saveContext () {
    if let moc = self.managedObjectContext {
        var error: NSError? = nil
        if moc.hasChanges && !moc.save(&error) {
        //ERROR: CANNOT CONVERT VALUE OF TYPE 'INOUT NSERROR?'(AKA 'INOUT OPTIONAL<NSERROR>') TO EXPECTED ARGUMENT TYPE '()'
            NSLog("Unresolved error \(error), \(error!.userInfo)")
            abort()
        }
    }
}

I've attempted to manually debug this but my inexperience in both editing the AppDelegate and using swift have let me down as every error I remove is accompanied by some new errors.

Upvotes: 1

Views: 540

Answers (1)

joern
joern

Reputation: 27620

The method signature of addPersistentStoreWithType has changed. It is now throwable and has to be used like this:

do {
    try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch {
    // Report any error we got.
    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)
    // Replace this with code to handle the error appropriately.
    // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
    print("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
    abort()
}

Same with the save method on NSManagedObjectContext:

func saveContext () {
    if managedObjectContext!.hasChanges {
        do {
            try managedObjectContext!.save()
        } catch {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            let nserror = error as NSError
            print("Unresolved error \(nserror), \(nserror.userInfo)")
            abort()
        }
    }
}

Upvotes: 4

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