CoreData implementation swift 3 - swift

Question

I'm having problems implementing coredata in my project. it seems to be able to save but not to fetch. here's the code
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "Utente", in: context)
let item = NSManagedObject(entity: entity!, insertInto: context)
var utente: Profilo? = nil
let vc = CustomTabBarController() as UIViewController
let vc1 = LoginController() as UIViewController
// Configure Fetch Request
do {
let request: NSFetchRequest<NSFetchRequestResult> = Profilo.fetchRequest()
let result = try context.fetch(request) as Profilo
utente = result as Profilo
print()
if utente?.type != nil {
if utente?.type == "students"{
print("students")
present(vc, animated: true, completion: nil)
}
if utente?.type == "parents"{
print("parents")
present(vc, animated: true, completion: nil)
}
if utente?.type == "teachers"{
print("teachers")
present(vc, animated: true, completion: nil)
}
} else {
print("variable type empty")
present(vc1, animated: true, completion: nil)
}
} catch {
let fetchError = error as NSError
print(fetchError)
}
i also get the error on the result line:
cannot invoke 'fetch' with an argument list of type (NSFetchRequest)

Answer 1

The syntax is supposed to be
let request: NSFetchRequest<Profilo> = Profilo.fetchRequest()
let result = try context.fetch(request) as! [Profilo] // returns always an array.
Consider that the default initializers CustomTabBarController() and LoginController() won't work.

Answer 2

As we agreed I'm posting my core data functions, they may not be the best way but they work in my project. My entity is called Goals.
// MARK: - Core data funcitons
func loadCoreData(){
goalsArray.removeAll()
//let request = NSFetchRequest<Goals>(entityName:"Goals")
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
do{
let fetchRequest : NSFetchRequest<Goals> = Goals.fetchRequest() as! NSFetchRequest<Goals>
let sortDescriptor = NSSortDescriptor(key: "id", ascending: false)
fetchRequest.sortDescriptors = [sortDescriptor]
let result = try context.fetch(fetchRequest)
for result in result {
goalsArray.append(result)
print("Fetched result goaltitle is \(result.goalTitle!)")
}
tableView.reloadData()
print("I've fetched the results")
}
catch {
fatalError("Sthh")
}
}
func countCoreDataObjects()-> Bool{
//let request = NSFetchRequest<Goals>(entityName:"Goals")
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
do{
let fetchRequest : NSFetchRequest<Goals> = Goals.fetchRequest() as! NSFetchRequest<Goals>
let result = try context.fetch(fetchRequest)
if result.count == 0 {
return false
} else {return true
}
}
catch {
fatalError("Sthh")
}
}
func saveToCD(object: goalClassForPassing){
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "Goals", in: context)
let goal = NSManagedObject(entity: entity!, insertInto: context) as! Goals
goal.goalTitle = object.goalName
goal.id = String(describing:Date())
goal.imagePath = object.imagePath
do {
try context.save()}
catch {
fatalError("couldn't save to core data")
}
goal.id = String(describing: Date())
goalObjectToSaveToCD?.id = String(describing: NSDate())
print(goalObjectToSaveToCD?.goalTitle)
print("Saved \(goal.goalTitle) - \(goal.id) - \(goal.imagePath) to Core Data")
loadCoreData()
}