我已将标签栏隐藏在我的标签栏控制器中，并改为使用集合视图作为程序的主菜单。为什么？我花了2个小时使它看起来像所需的；标签栏很难根据我的需要进行自定义，我花了数小时没有结果。其余的只是一个标准的控制器。集合视图的委托为选项卡栏控制器设置选定的索引；它工作正常；我唯一的问题来自隐藏标签栏：子视图控制器正在从下方扩展到集合视图的顶部；转到屏幕底部。有没有一种方法可以为VC设置容器，以使子对象的底部位于标签栏可见的位置？我可以这样做但不使用标签栏/将容器的底部与屏幕底部保持一定距离吗？下面的代码，谢谢。

class ProgramMainmenu: UITabBarController {
    //MARK: - Properties.
    fileprivate lazy var programMainmenu: MenuTypeCV = {
        let mainmenu = MenuTypeCV(frame: .zero,collectionViewLayout: UICollectionViewFlowLayout())
        mainmenu.defaultSelectedMenuTab = IndexPath(item: 0,section: 0)
        mainmenu.delegate = self
        mainmenu.dataSource = self
        mainmenu.backgroundColor = UIColor.customColoursForAllElements(colourName: "background blue")
        return mainmenu
    }()
    //MARK: - Init.
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.customColoursForAllElements(colourName: "background blue")
        programMainmenu.register(MainmenuTab.self,forCellWithReuseIdentifier: cellID)
        navigationController?.navigationBar.isHidden = true
        self.tabBar.isHidden = true
        loadchildviewcontrollers()
        setMainmenuView()

    }
    //MARK: - Functions.
    fileprivate func setMainmenuView() {
        view.addSubview(programMainmenu)
        let mainmenuConstraints = [
            programMainmenu.bottomAnchor.constraint(equalTo: view.bottomAnchor,constant: -2),programMainmenu.leadingAnchor.constraint(equalTo: view.leadingAnchor,constant: 8),programMainmenu.trailingAnchor.constraint(equalTo: view.trailingAnchor,constant: -8),programMainmenu.heightAnchor.constraint(equalToConstant: 93)
        ]
        NSLayoutConstraint.activate(mainmenuConstraints)
    }
    fileprivate func loadchildviewcontrollers() {
         let test1 = FirstTestController()
         let nav1 = UINavigationController(rootViewController: test1)
         nav1.navigationBar.isHidden = true

         let test2 = SecondTestController()
         let nav2 = UINavigationController(rootViewController: test2)
         nav2.navigationBar.isHidden = true

         let test3 = ThirdTestController()
         let nav3 = UINavigationController(rootViewController: test3)
         nav3.navigationBar.isHidden = true

         let test4 = FourthTestController()
         let nav4 = UINavigationController(rootViewController: test4)
         nav4.navigationBar.isHidden = true

         let test5 = FifthTestController()
         let nav5 = UINavigationController(rootViewController: test5)
         nav5.navigationBar.isHidden = true

         viewControllers = [nav1,nav2,nav3,nav4,nav5]
     }
}

extension ProgramMainmenu: UICollectionViewDelegateFlowLayout,UICollectionViewDataSource {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    func collectionView(_ collectionView: UICollectionView,numberOfItemsInSection section: Int) -> Int {
        return mainmenuTabs.count
    }

    func collectionView(_ collectionView: UICollectionView,cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = programMainmenu.dequeueReusableCell(withReuseIdentifier: cellID,for: indexPath) as! MainmenuTab
        let tab = mainmenuTabs[indexPath.item]
        cell.mainmenuTab = tab
        return cell
    }
    func collectionView(_ collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,sizeForItemAt indexPath: IndexPath) -> CGSize {
           return CGSize(width: programMainmenu.frame.width / 5,height: programMainmenu.frame.height)
       }
    func collectionView(_ collectionView: UICollectionView,minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    func collectionView(_ collectionView: UICollectionView,minimumLinespacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    func collectionView(_ collectionView: UICollectionView,didSelectItemAt indexPath: IndexPath) {
        switch indexPath.item {
        case 0: self.selectedIndex = 0
        case 1: self.selectedIndex = 1
        case 2: self.selectedIndex = 2
        case 3: self.selectedIndex = 3
        case 4: self.selectedIndex = 4
        default: print("no such main tab")
        }
    }

}