Shake Animation for an Empty textfield in an UIAlertAction - ios

Question

I'm trying to make UIAlert shake when the textfield in the alert is empty, I use this textfield to add items to my array, and with the code I've used it doesn't add any empty values to my list but nor stay on UIAlertAction, so obviously the shaking animation doesn't show too, this is my code:
let action = UIAlertAction(title: "Add Item", style: .default) { (action) in
if textField.text?.isEmpty ?? true {
let animation = CABasicAnimation(keyPath: "position")
animation.duration = 0.07
animation.repeatCount = 4
animation.autoreverses = true
animation.fromValue = NSValue(cgPoint: CGPoint(x: textField.center.x - 10, y: textField.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: textField.center.x + 10, y: textField.center.y))
textField.layer.add(animation, forKey: "position")
} else {
self.itemArray.append(textField.text!)
self.tableView.reloadData()
}
}

Answer 1

Two things here, first just to help you here i'm adding a extension to shake functionality:
extension UIView {
func shake(duration timeDuration: Double = 0.07, repeat countRepeat: Float = 3){
let animation = CABasicAnimation(keyPath: "position")
animation.duration = timeDuration
animation.repeatCount = countRepeat
animation.autoreverses = true
animation.fromValue = NSValue(cgPoint: CGPoint(x: self.center.x - 10, y: self.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: self.center.x + 10, y: self.center.y))
self.layer.add(animation, forKey: "position")
}
}
So for you to use can be easy like, "your view".shake() it's more simple.
Second and most important is, you can't use this, or even the way that you were trying, because UITextField inherit from UIControl, and need to be from UIView, so the adjust for you is, just put your UITextFiel inside a UIView and add the shake functionality to the UIView and them will shake everything inside :D
If like up vote :D :D