调用并关闭搜索栏处于活动状态时，UICollectionView大小变得混乱

Question

我的主视图控制器是一个UICollectionViewController，其初始屏幕如下：

当用户点击其中一个选项时，然后使用不同的单元格重新加载集合视图，并在顶部添加一个新的第二个UICollectionView，如下所示：

所以现在有两个集合视图，它们都是水平滚动的。顶部条用于来回切换，底部用于选择。但是，底部是启用分页并水平滚动，因此为了获得垂直效果，集合视图的单元格实际上是一个集合视图。

我的问题是，当使用SearchController时，只要显示键盘，它就会抛弃布局并弄乱底部集合视图的大小。

如何处理键盘以使我的底部集合视图保持正确格式化？我也尝试设置navigationItem.searchController = searchController，但我不希望搜索栏位于导航栏的底部，我无法解除它，所以我设置的是navigationItem.titleView = searchController.searchBar。

以下是我正在使用的一些代码：

import UIKit

class MainPageController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    let cellId = "mainCellId"
    let secondCellId = "secondCellId"

    var filteredDisplay: [String] = [String]()
    var fullDisplayData: [String] = [String]()

    lazy var topTabSectionBar: TopTabSectionBar = {
        let cv = TopTabSectionBar()
        cv.mainPageController = self
        return cv
    }()

    var tabBarHidden: NSLayoutConstraint?
    var titleView: UIView!

    let searchController = UISearchController(searchResultsController: nil)

    override func viewDidLoad() {
        super.viewDidLoad()

        setupCollectionView()
        configureSearchBar()
        setupSearchIcon()

    }

    func configureSearchBar() {
        // Setting up the Search Controller
        searchController.searchResultsUpdater = self
        searchController.obscuresBackgroundDuringPresentation = false
        searchController.searchBar.placeholder = "Search"

        titleView = navigationItem.titleView
        searchController.hidesNavigationBarDuringPresentation = false
        definesPresentationContext = true
        searchController.searchBar.delegate = self

    }

    private func setupSearchIcon() {
        let searchIcon = UIImage(named: "searchicon")?.withRenderingMode(.alwaysTemplate)
        let searchBarButtonItem = UIBarButtonItem(image: searchIcon, style: .plain, target: self, action: #selector(showSearch))

        navigationItem.rightBarButtonItem = searchBarButtonItem

    }

    @objc func showSearch() {

        if navigationItem.titleView == titleView {
            navigationItem.titleView = searchController.searchBar
            collectionView?.reloadData()
            navigationController?.view.layoutSubviews()
        } else {
            navigationItem.titleView = titleView
            collectionView?.reloadData()
            navigationController?.view.layoutSubviews()
        }

    }

    func setupCollectionView() {

        collectionView?.backgroundColor = .clear
        view.backgroundColor = .white
        collectionView?.register(SecondCollectionView.self, forCellWithReuseIdentifier: secondCellId)
        collectionView?.register(MainCell.self, forCellWithReuseIdentifier: cellId)

        collectionView?.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
        collectionView?.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 0, 0)

    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if (self.tabBarHidden?.isActive)! {
            return mainPageOptions.options.count
        } else {
            return 10
        }
    }

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if (self.tabBarHidden?.isActive)! {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! MainCell

            return cell
        } else {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: secondCellId, for: indexPath) as! SecondCollectionView
            if isFiltering() {
                cell.displayData = filteredDisplay
                return cell
            } else {
                cell.displayData = fullDisplayData
                return cell
            }
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        if (self.tabBarHidden?.isActive)! {
            let itemSize = CGSize(width: view.frame.width, height: mainPageOptions.cvHeight)
            return itemSize
        } else {
            let itemSize = CGSize(width: view.frame.width, height: view.frame.height - 50)
            return itemSize
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }

    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        DispatchQueue.main.async {
            self.tabBarHidden?.isActive = false
            if let flowLayout = self.collectionView?.collectionViewLayout as? UICollectionViewFlowLayout {
                flowLayout.scrollDirection = .horizontal
                flowLayout.minimumLineSpacing = 0
            }
            self.collectionView?.isPagingEnabled = true
            self.collectionView?.contentInset = UIEdgeInsetsMake(50, 0, 0, 0)
            self.collectionView?.scrollIndicatorInsets = UIEdgeInsetsMake(50, 0, 0, 0)
            self.collectionView?.reloadData()
        }
    }

}

extension MainPageController: UISearchResultsUpdating {
    func updateSearchResults(for searchController: UISearchController) {

    }
}

extension MainPageController: UISearchBarDelegate {

}

我会使用任何方法来显示搜索栏，但我现在正在这样做，点击搜索图标然后显示搜索栏，会大大搞乱集合视图布局。

我的问题是：如何让搜索栏工作，根本不移动集合视图，或者正确移动它？

在显示键盘之前，它确实没有任何问题。