ViewController Interactive transition pan gesture recognizer

Question

I'm trying to add interactive transition to modal presentation of my view controller. I add pangesturerecognize to detect user's touches and move the view. I have just read a lot of articles about custom transitions and in every article authors call dismiss method in the beginning:

func handleGesture(_ gestureRecognizer: UIScreenEdgePanGestureRecognizer)
    switch gestureRecognizer.state {
    case .began:
      interactionInProgress = true
      viewController.dismiss(animated: true, completion: nil)
      ...
}

I've tried to remove this method and this still working. Can someone explain why we need to call dismiss(animated: true, completion: nil) in the beginning of handling gestures?

Answer 1

It doesn't make any sense for Gesture.Maybe the articles you read are from one author or maybe they copied the same source.