Swift Lottie动画

Question

使用此代码在我的应用程序中创建一个Lottie动画。 某种程度上，我在UI中看不到任何结果。您是否知道错误在哪里？

导入基金会 导入UIKit 进口乐透

TestAnimation2类：UIViewController {

var menuOn = false
var menuButton: LOTAnimationView?
var itemButtonFrame = CGRect(x: 0, y: 70, width: 100, height: 100)

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

//um es interaktiv / touchable zu machen
func addToggleRecognizer(_ animationView: LOTAnimationView) {
    let tapRecognizer = UITapGestureRecognizer(target: self, action: #selector(toggleMenu(recognizer:)))
    animationView.addGestureRecognizer(tapRecognizer)
}


func addMenuButton(_ on: Bool) {
    //if exists "reset" the state to nil
    if menuButton != nil {
        self.menuButton?.removeFromSuperview()
        self.menuButton = nil
    }

    let animation = menuOn ? "checkon" : "checkoff"
    menuButton = LOTAnimationView(name: animation)
    guard let menuButton = menuButton else {
        return
    }
    menuButton.isUserInteractionEnabled = true
    menuButton.frame = itemButtonFrame
    menuButton.contentMode = .scaleAspectFill
    addToggleRecognizer(menuButton)
    view.addSubview(menuButton)
}

@objc func toggleMenu(recognizer: UITapGestureRecognizer) {
    menuOn ? setMenuOffAndPerformAction() : setMenuOnAndPerformAction()
}
func setMenuOnAndPerformAction() {
    menuButton?.play(completion: { (success) in

        self.menuOn = true
        self.addMenuButton(self.menuOn)
        DispatchQueue.main.async {
            print("menu is ON")
            //update UI on main thread
        }
    })
}
func setMenuOffAndPerformAction() {

    menuButton?.play(completion: { (success) in
        self.menuOn = false
        self.addMenuButton(self.menuOn)
        DispatchQueue.main.async {
            print("menu is OFF")
            //update UI on main thread
        }
    })
}

}

预先感谢！