Sort CoreData results using NSPredicate in Swift

Question

I\'m currently writing a simple phone book app in Swift and need to sort the results from a CoreData query.

Basically, I set up an NSManagedObject called \"Directory

Answer 1

I used the above answer from Oliver Spencer, because the sorting approach includes pending changes, which the "max" approach dose not (see apple documentation on NSFetchRequest).

Here my code for convenience:

func fetch_biggestImageID() -> Int {

    print("Fetching biggest ImageID")
    let request: NSFetchRequest<CD_Image> = CD_Image.fetchRequest()
    request.sortDescriptors = [NSSortDescriptor(key: "id", ascending: false)]
    request.fetchLimit = 1

    var maxValue: Int64? = nil
    do {
        let result = try self.managedObjectContext.fetch(request)
        maxValue = result.first?.id
    } catch {
        fatalError("Unresolved error while retrieving max imageID value \(error)")
    }

    return  Int(truncatingIfNeeded:  maxValue ?? 0 )
}

Answer 2

Thanks - The following lines were required before the request.predicate line:

let sortDescriptor = NSSortDescriptor(key: "name_f", ascending: true)
let sortDescriptors = [sortDescriptor]
request.sortDescriptors = sortDescriptors