How to FULLY re-enable back/left swipe gesture in UINavigationController after unwind from popped view?

问题

After unwind from a popped view, my back/left swipe gesture is gone. I fixed by:

override func viewDidLoad() {
  super.viewDidLoad()
  reenableSwipeBack()
}

func reenableSwipeBack() {
  self.navigationController?.interactivePopGestureRecognizer?.isEnabled = true;
  self.navigationController?.interactivePopGestureRecognizer?.delegate = nil;
}

My swipe gesture is back but without animation (Shown here (Giphy)). How can I get the gesture animation back?

来源：https://stackoverflow.com/questions/45268086/how-to-fully-re-enable-back-left-swipe-gesture-in-uinavigationcontroller-after-u