swift3.0 点击UIScrollView中输入框之外的区域关闭键盘

scrollView: UIScrollView!
title_textField: UITextField!

let hideKeyboardTapGesture = UITapGestureRecognizer(target: self, action: #selector(hideKeyboardTapGesture(sender:)))
scrollView.isUserInteractionEnabled = true
scrollView.addGestureRecognizer(hideKeyboardTapGesture)

func hideKeyboardTapGesture(sender: UITapGestureRecognizer){
        title_textField.resignFirstResponder()
}