防止滑动函数中的多重方法调用

我创建了一个滑块,该滑块从一条边移动到另一条边,拖动后返回到其原始位置。当它到达幻灯片的末尾时,我调用一个函数,但我现在面临的问题是,当它移动到末尾时,该函数被调用多次,应该只调用一次。我如何让这个滑块只调用一次而不是多次,因为如果用户决定在最后保持它不动,该方法将被重复调用。到目前为止,我的代码是bleow

override func viewDidLoad() {
        super.viewDidLoad()

        let swipeGesture = UIPanGestureRecognizer(target: self, action: #selector(acknowledgeSwiped(sender:)))
        swipeImage.addGestureRecognizer(swipeGesture)
        swipeImage.isUserInteractionEnabled = true
        swipeGesture.delegate = self as? UIGestureRecognizerDelegate
    }
var startingFrame: CGRect?
    @objc func acknowledgeSwiped(sender: UIPanGestureRecognizer) {
        if let sliderView = sender.view {
            let translation = sender.translation(in: swipeView)
            switch sender.state {
            case .began:
                startingFrame = swipeImage.frame
                fallthrough
            case .changed:
                if let startFrame = startingFrame {

                    var movex = translation.x
                    if movex < -startFrame.origin.x { movex = -startFrame.origin.x }

                    let xMax = swipeView.frame.width - startFrame.origin.x - startFrame.width
                    if movex > xMax {
                        movex = xMax
                        acknowledgeTrip()
                    }

                    var movey = translation.y
                    if movey < -startFrame.origin.y { movey = -startFrame.origin.y }

                    let yMax = swipeView.frame.height - startFrame.origin.y - startFrame.height
                    if movey > yMax {
                        movey = yMax

                    }

                    sliderView.transform = CGAffineTransform(translationX: movex, y: movey)
                }
            default: // .ended and others:
                UIView.animate(withDuration: 0.1, animations: {
                    sliderView.transform = CGAffineTransform.identity
                })
            }
        }
    }

任何帮助都将不胜感激