放置在NavigationController下后无法展开视图

Question

我试图以编程方式将一个包含nib文件的视图放置在navigationcontroller下。用户交互时，视图应展开。我在此处使用YNDropDownMenu将视图放置在嵌入式导航控制器下，当用户单击该视图时，该视图将展开。它是一个nibfile，已添加到视图并添加到页面。工作时看起来像这样：

Menu Example

以编程方式添加约束时，我得到了：

我正在使用这些约束将视图放置在导航控制器下：

// Add Filter Menu
        let ZBdropDownViews = Bundle.main.loadNibNamed("DropDownViews", owner: nil, options: nil) as? [UIView]
        let FFA409 = UIColor.init(red: 239/255, green: 239/255, blue: 244/255, alpha: 1.0)



        if let _pokeDownViews = PokeDownViews {
            // Inherit YNDropDownView if you want to hideMenu in your dropDownViews
            let view = YNDropDownMenu(frame: CGRect(x: 0, y: (navigationController?.navigationBar.frame.height)! + 20, width: (navigationController?.navigationBar.frame.width)! + 15, height: 45), dropDownViews: _pokedropDownViews, dropDownViewTitles: ["Sort By"])
            
            
            
            view.setImageWhens(normal: [UIImage(named: "Search"),UIImage(named: "Leaf Icon"),UIImage(named: "Leaf Icon"),UIImage(named: "Leaf Icon")], selectedTintColorRGB: "FFA409", disabledTintColorRGB: "D3D3D3")




            view.setLabelColorWhen(normal: .purple, selected: FFA409, disabled: .purple)
                        view.setLabelColorWhen(normalRGB: "000000", selectedRGB: "FFA409", disabledRGB: "D3D3D3")

            view.setLabelFontWhen(normal: .systemFont(ofSize: 12), selected: .boldSystemFont(ofSize: 16), disabled: .systemFont(ofSize: 16))
            //            view.setLabel(font: .systemFont(ofSize: 12))

            view.backgroundBlurEnabled = true
            //  view.bottomLine.backgroundColor = UIColor.black

            view.bottomLine.isHidden = false
            // Add custom blurEffectView






            self.view.addSubview(view)

            self.edgesForExtendedLayout = []//Optional our as per your view ladder


            view.translatesAutoresizingMaskIntoConstraints = false

            if #available(iOS 11.0, *) {
                let guide = self.view.safeAreaLayoutGuide
                view.trailingAnchor.constraint(equalTo: guide.trailingAnchor).isActive = true
                view.leadingAnchor.constraint(equalTo: guide.leadingAnchor).isActive = true
                view.topAnchor.constraint(equalTo: guide.topAnchor).isActive = true
                view.heightAnchor.constraint(equalToConstant: 50).isActive = true
            } else {
                NSLayoutConstraint(item: view,
                                   attribute: .top,
                                   relatedBy: .equal,
                                   toItem: view, attribute: .top,
                                   multiplier: 1.0, constant: 0).isActive = true
                NSLayoutConstraint(item: view,
                                   attribute: .leading,
                                   relatedBy: .equal, toItem: view,
                                   attribute: .leading,
                                   multiplier: 1.0,
                                   constant: 0).isActive = true
                NSLayoutConstraint(item: view, attribute: .trailing,
                                   relatedBy: .equal,
                                   toItem: view,
                                   attribute: .trailing,
                                   multiplier: 1.0,
                                   constant: 0).isActive = true

                view.heightAnchor.constraint(equalToConstant: 50).isActive = true
            }


            let backgroundView = UIView()
            backgroundView.backgroundColor = .black
            view.blurEffectView = backgroundView
            view.blurEffectViewAlpha = 0.85

            // Open and Hide Menu
            //            view.alwaysSelected(at: 0)
            //            view.disabledMenuAt(index: 2)
            //view.showAndHideMenuAt(index: 3)

            view.setBackgroundColor(color: UIColor.groupTableViewBackground)
            backgroundView.layer.borderWidth = UIScreen.main.bounds.width
            //            view.layer.borderWidth = UIScreen.main.bounds.width


            view.layer.cornerRadius = 7


            PokedropDownViews?.forEach({ (dropDownView) in
                if dropDownView.isKind(of: PokeFilterMemeView.self) {
                    (dropDownView as? PokeFilterMemeView)?.menuViewDelegate = self
                }

            })


        

单击时，视图应展开，以便用户可以看到视图中包含的所有项目，但是，我似乎无法扩展视图。

我不确定该如何解决。有人可以帮我吗？

谢谢。