CODEWITHSUNDEEP
ioscore-datanspredicate
Mych
Mych

Reputation: 2553

Predicate for NSNumber = 0

I have the following code fetching results from core data to populate a tableview.

private lazy var fetchedResultsController: NSFetchedResultsController = {
    // Initialize Fetch Request
    let fetchRequest = NSFetchRequest(entityName: "MileageLog")

    // Add Sort Descriptors
    let dateSort = NSSortDescriptor(key: "logDate", ascending: true)
    let mileSort = NSSortDescriptor(key: "mileage", ascending: true)
    fetchRequest.sortDescriptors = [dateSort, mileSort]

    //// Create a new predicate that filters out any object that
    //// have not been exported.
    // let predicate = NSPredicate(format: "wasExported == %@", 0)

    //// Set the predicate on the fetch request
    // fetchRequest.predicate = predicate

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

    // Initialize Fetched Results Controller
    let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)

    fetchedResultsController.delegate = self

    return fetchedResultsController

}()

Without the predicate the tableview is populated with all records sorted correctly. Uncommenting the two lines to bring the predicate into force returns no results at all. My dataset has 4 records with wasExported == 1 and 3 with wasExported == 0... wasExported is a Boolean but in core data it is stored as NSNumber..... what have I done wrong?

Upvotes: 0

Views: 750

Answers (1)

rmaddy
rmaddy

Reputation: 318824

You are using the wrong format specifier in your predicate. You want:

let predicate = NSPredicate(format: "wasExported == %d", 0)

%@ is for object pointers. With %@, the 0 is interpreted as the nil pointer.

Upvotes: 3

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