uitextfield numbers only
//class ViewController: UIViewController, UITextInputTraits { @IBOutlet weak var textFieldKeyboardType: UITextField!{ didSet{ textFieldKeyboardType.keyboardType = UIKeyboardType.NumberPad } } var keyboardType: UIKeyboardType { get{ return textFieldKeyboardType.keyboardType } set{ if newValue != UIKeyboardType.NumberPad{ self.keyboardType = UIKeyboardType.NumberPad } } }