AddTaskViewController.swift

class AddTaskViewController: UIViewController {
 @IBOutlet weak var taskTextField: UITextField!
 override func viewDidLoad() {
 super.viewDidLoad()
}
 @IBAction func buttonTapped(_ sender: UIButton) {
  let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
  let task = Task(context: context) // Link Task & Context
  task.name = taskTextField.text!
   
 // Save the data to coredata
  (UIApplication.shared.delegate as! AppDelegate).saveContext()
   
  let _ = navigationController?.popViewController(animated: true)
 }
}