prior swift 3 i was adding shadow in my UIView like this :
//toolbar is an UIToolbar (UIView) toolbar.layer.masksToBounds = false toolbar.layer.shadowOffset
This works for me (Swift 3 and 4)
yourView.layer.shadowColor = UIColor.gray.cgColor yourView.layer.shadowOpacity = 0.3 yourView.layer.shadowOffset = CGSize.zero yourView.layer.shadowRadius = 6