在UIView代码中创建的UIgestureRecognitor不工作

我有一个自定义子类 UIStackView 有一些 UIImageViews 在里面。我希望视图接受平移手势,以跟踪在其曲面上的缓慢滑动。配置时 UIPanGestureRecognizer 在Interface Builder中可以工作,但在代码中不能工作。以下是该课程的缩写版本:

@IBDesignable
class CustomView: UIStackView {

    private let panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(CustomView.singleFingerSwipe))


    override init(frame: CGRect) {
        super.init(frame: frame)

        initializeProperties()
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        initializeProperties()
    }

    @IBAction
    private func singleFingerSwipe(_ sender: UIPanGestureRecognizer) {
        print("Panning...")
    }

    private func initializeProperties() {
        addGestureRecognizer(panRecognizer)

        for _ in 1...3 {
            let imageView = UIImageView(image: UIImage(named: "MyImage"))
            imageView.translatesAutoresizingMaskIntoConstraints = false
            imageView.isUserInteractionEnabled = true

            addArrangedSubview(imageView)
            imageView.widthAnchor.constraint(equalTo: imageView.heightAnchor).isActive = true
            imageView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true
        }
    }
}

当我在星图中四处滑动时,没有输出打印。但是,如果我将平移手势识别器放到IB中的视图上,并将其连接到同一个选择器上,它就可以正常工作。我错过了什么?