textField实现左图右文字

let imageview = UIImageView(image: UIImage(named: "contacts"))
        imageview.isUserInteractionEnabled = true
// 手势添加，  showContactsList
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(showGesture))
        imageview.addGestureRecognizer(tapGesture)
        textfield.leftView = imageview
        textfield.leftViewMode = UITextFieldViewMode.unlessEditing
        textfield.clearButtonMode = UITextFieldViewMode.whileEditing

func showGesture() {
}