How to dismiss number keyboard after tapping outside of the textfield

viewdidload()
{

let tapRecognizer = UITapGestureRecognizer()
tapRecognizer.addTarget(self, action: #selector(ViewController.didTapView))
self.view.addGestureRecognizer(tapRecognizer)

}

func didTapView(){
  self.view.endEditing(true)
}