In iOS, how to drag down to dismiss a modal?

Question

A common way to dismiss a modal is to swipe down - How do we allows the user to drag the modal down, if it\'s far enough, the modal\'s dismissed, otherwise it animates back

Answer 1

Only vertical dismiss

func panGestureAction(_ panGesture: UIPanGestureRecognizer) {
    let translation = panGesture.translation(in: view)

    if panGesture.state == .began {
        originalPosition = view.center
        currentPositionTouched = panGesture.location(in: view)    
    } else if panGesture.state == .changed {
        view.frame.origin = CGPoint(
            x:  view.frame.origin.x,
            y:  view.frame.origin.y + translation.y
        )
        panGesture.setTranslation(CGPoint.zero, in: self.view)
    } else if panGesture.state == .ended {
        let velocity = panGesture.velocity(in: view)
        if velocity.y >= 150 {
            UIView.animate(withDuration: 0.2
                , animations: {
                    self.view.frame.origin = CGPoint(
                        x: self.view.frame.origin.x,
                        y: self.view.frame.size.height
                    )
            }, completion: { (isCompleted) in
                if isCompleted {
                    self.dismiss(animated: false, completion: nil)
                }
            })
        } else {
            UIView.animate(withDuration: 0.2, animations: {
                self.view.center = self.originalPosition!
            })
        }
    }