CODEWITHSUNDEEP
iosswiftcore-data
Koh
Koh

Reputation: 2897

Swift fetchResultsController: Instance member cannot be used on type 'ViewController'

I am working on the CoreData project on Udacity and am having difficulty implementing fetchedResultsController. I attempted to instantiate fetchedResultsController with a lazy var but it prompts me "Instance member context cannot be used on type 'ViewController'. My codes as such:

//AppDelegate
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    let stack = CoreDataStack(modelName: "Model")
    ... 
}

//ViewController
class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, MKMapViewDelegate{

    lazy var context: NSManagedObjectContext = {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        return appDelegate.stack!.context
    }()

    lazy var fetchedResultsController: NSFetchedResultsController<NSFetchRequestResult> = {
        let fetchedRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Photo")
        fetchedRequest.sortDescriptors = []

        return NSFetchedResultsController(fetchRequest: fetchedRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
    }()

Doing so will give me an error line at the 'context' in fetchedResultsController indicating:

Instance member 'context' cannot be used on type 'ViewController'

Is there anything I'm doing wrong? Any advice is much appreciated, thanks!

Upvotes: 1

Views: 846

Answers (1)

Andreas Oetjen
Andreas Oetjen

Reputation: 10199

You need to explicitly use self when referring to context in the lazy property:

return NSFetchedResultsController(fetchRequest: fetchedRequest, managedObjectContext: self.context, sectionNameKeyPath: nil, cacheName: nil)

Upvotes: 2

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