CODE EXAMPLE FOR SWIFT

how to add dragdown gesture recognizer on view

class ViewConrtoller: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(onDrage(_:))))
    }

    @objc func onDrage(_ sender:UIPanGestureRecognizer) {
        let percentThreshold:CGFloat = 0.3
        let translation = sender.translation(in: view)
    
        let newX = ensureRange(value: view.frame.minX + translation.x, minimum: 0, maximum: view.frame.maxX)
        let progress = progressAlongAxis(newX, view.bounds.width)
    
        view.frame.origin.x = newX //Move view to new position
    
        if sender.state == .ended {
            let velocity = sender.velocity(in: view)
           if velocity.x >= 300 || progress > percentThreshold {
               self.dismiss(animated: true) //Perform dismiss
           } else {
               UIView.animate(withDuration: 0.2, animations: {
                   self.view.frame.origin.x = 0 // Revert animation
               })
          }
       }
    
       sender.setTranslation(.zero, in: view)
    }
}

func progressAlongAxis(_ pointOnAxis: CGFloat, _ axisLength: CGFloat) -> CGFloat {
        let movementOnAxis = pointOnAxis / axisLength
        let positiveMovementOnAxis = fmaxf(Float(movementOnAxis), 0.0)
        let positiveMovementOnAxisPercent = fminf(positiveMovementOnAxis, 1.0)
        return CGFloat(positiveMovementOnAxisPercent)
    }
    
    func ensureRange<T>(value: T, minimum: T, maximum: T) -> T where T : Comparable {
        return min(max(value, minimum), maximum)
    }