Add return keys UITextField

UIActionReturnTextField.swift

class UIActionReturnTextField: UITextField {
  func addDoneCancelToolbar(onDone: (target: Any, action: Selector)? = nil, onCancel: (target: Any, action: Selector)? = nil) {
      let onCancel = onCancel ?? (target: self, action: #selector(cancelButtonTapped))
      let onDone = onDone ?? (target: self, action: #selector(doneButtonTapped))

      let toolbar: UIToolbar = UIToolbar()
      toolbar.barStyle = .default
      toolbar.items = [
          UIBarButtonItem(title: "Cancel", style: .plain, target: onCancel.target, action: onCancel.action),
          UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil),
          UIBarButtonItem(title: "Done", style: .done, target: onDone.target, action: onDone.action)
      ]
      toolbar.sizeToFit()

      self.inputAccessoryView = toolbar
  }

  // Default actions:
  @objc func doneButtonTapped() { self.resignFirstResponder() }
  @objc func cancelButtonTapped() { self.resignFirstResponder() }
}