AlertController is being popped every time in nested conditions swift ios

Question

I have defined an alertcontroller when username or password is not correct the alert should pop, and it is working fine. but when the username & password is matched despite

Answer 1

if your result contains multiple different element then else block will execute multiple time. thats why alert appeared multiple time . when you found a match then you should return . if no match found then after loop alert will appear for one time .

Use this:

       @IBAction func loginAction(_ sender: Any) {

            let appDel = UIApplication.shared.delegate as! AppDelegate
            let context = appDel.persistentContainer.viewContext

            let request = NSFetchRequest(entityName: "Users")
            request.returnsObjectsAsFaults = false
            //  request.predicate = NSPredicate(format: "username = %@", "" + emailText.text!)


            do {

                let results = try! context.fetch(request)

                if(results.count > 0){

                    for result in results as! [NSManagedObject]
                    {


                        if  emailText.text == result.value(forKey: "username") as? String && passText.text == result.value(forKey: "password") as? String {
                            print(emailText.text!, passText.text!)
                            usernameGlobal = self.emailText.text!
                            let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle : nil)
                            let desController = mainStoryBoard.instantiateViewController(withIdentifier: "AddViewController") as! AddViewController
                            let newFrontViewController = UINavigationController.init(rootViewController:desController)
                            revealViewController().pushFrontViewController(newFrontViewController, animated: true)
                            return

                        }
                    }
                    let alertController = UIAlertController(title: "Oops!", message: "Incorrect username or password", preferredStyle: .alert)

                    let defaultAction = UIAlertAction(title: "OK", style: .default, handler: nil)
                    alertController.addAction(defaultAction)

                    present(alertController, animated: true, completion: nil)

                }
            }
        }