问我想在我的ios应用程序中用指令实现灰色预测

EN

 var vc: BannerViewController!

    func addBanner(){
        vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(identifier: "BannerViewController")
        UIApplication.shared.keyWindow?.addSubview(vc.view)
        let sv = vc.view.superview!
        vc.view.translatesAutoresizingMaskIntoConstraints = false
        let constrainst = [
            vc.view.topAnchor.constraint(equalTo: sv.topAnchor),
            vc.view.leadingAnchor.constraint(equalTo: sv.leadingAnchor),
            vc.view.bottomAnchor.constraint(equalTo: sv.bottomAnchor),
            vc.view.trailingAnchor.constraint(equalTo: sv.trailingAnchor)
        ]
        vc.view.isUserInteractionEnabled = true
        vc.view.backgroundColor = UIColor.red
        NSLayoutConstraint.activate(constrainst)
    }

    func removeBanner(){
        vc.view.removeFromSuperview()
        vc = nil
    }