无法显示UISearchController

Question

我有以下视图层次结构：

                         UINavigationController
                                  ||
                                  \/
           LibraryTableViewController: UITableViewController
                                  ||
                                  \/
       AlbumsCollectionViewController: UICollectionViewController
                                  ||
                                  \/
             SongsTableViewController: UITableViewController

我希望在AlbumsCollectionViewController中有一个搜索栏，在SongsTableViewController中有一个不同的搜索栏，这个搜索栏显示在navigationItem.titleView中。

我设法在AlbumsCollectionViewController中添加了一个工作搜索栏，如下所示：

class AlbumsCollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout, UISearchControllerDelegate, UISearchResultsUpdating, UISearchBarDelegate {

    var searchController : UISearchController!

    override func viewDidLoad() {
        super.viewDidLoad()

        initSearchBar()
        initNavigationBar()
    }

    private func initSearchBar() {
        self.searchController = UISearchController(searchResultsController:  nil)

        self.searchController.searchResultsUpdater = self
        self.searchController.delegate = self
        self.searchController.searchBar.delegate = self

        self.searchController.hidesNavigationBarDuringPresentation = false
        self.searchController.dimsBackgroundDuringPresentation = false

        searchController.searchResultsController?.view.isHidden = false
        searchController.hidesNavigationBarDuringPresentation = false

        self.extendedLayoutIncludesOpaqueBars = true
        self.definesPresentationContext = true

        searchController.searchBar.backgroundColor = UIColor.black
        UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).setTitleTextAttributes([NSAttributedStringKey.foregroundColor : UIColor.white], for: .normal)

        self.navigationItem.titleView = searchController.searchBar

        navigationItem.titleView?.isHidden = true
    }

    private func initNavigationBar() {
        searchButton.tintColor = UIColor.white
        settingsButton.tintColor = UIColor.white
        backButton.tintColor = UIColor.white
        self.navigationItem.title = "Artists"
        self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor : UIColor.white]
    }


    @IBAction func SearchButtonTapped(_ sender: Any) {
        showSearchBar()
    }


    private func showSearchBar(){
        navigationItem.titleView?.isHidden = false
        searchController.isActive = true
    }
}

请注意，搜索栏隐藏在ViewDidLoad()上，并在按下按钮时出现，如SearchButtonTapped方法中所示。

现在，我试图在SongsTableViewController中做同样的事情，但是，当点击按钮(即调用SearchButtonTapped)时，搜索栏没有显示，我得到了以下消息：

Warning: Attempt to present <UISearchController: 0x7f8158812b50> on <MyProject.AlbumsCollectionViewController: 0x7f81588023c0> whose view is not in the window hierarchy!

如果我评论了行searchController.isActive = true，那么搜索栏将显示，但是，即使我点击它，它也不会是活动的。

编辑

抱歉我没说清楚。我在SongsTableViewController中有一个单独的SongsTableViewController。我的意思是在两个控制器中使用相同的逻辑。

还请注意，如果我从导航控制器(即视图层次结构只有2个控制器( SongsTableViewController => SongsTableViewController) )中推送，则搜索栏工作良好()

这是SongsTableViewController (省略的非相关内容)的大部分代码

import UIKit
import os.log
import MediaPlayer

class SongsTableViewController: UITableViewController, UISearchControllerDelegate, UISearchResultsUpdating, UISearchBarDelegate ,PlayerDelegate, NowPlayingDelegate, SongCellDelegate, SongsOptionsDelegate {

    // MARK: properties

    var playerManager: PlayerManager? = nil
    var dataManager: DataManager? = nil

    var tabVC: TabBarController?
    var selectedSong: Song?

    lazy var optionsTransitionDelegate = PresentationManager()
    lazy var playlistTransitionDelegate = PresentationManager()

    var searchController : UISearchController!

    @IBOutlet var backgroundView: UIView!
    @IBOutlet weak var searchButton: UIBarButtonItem!
    @IBOutlet weak var settingsButton: UIBarButtonItem!

    var albumID: String?
    var artistID: String?
    var playlist: Playlist?

    var songs = [Song]()
    var songIndexMap = [String: Int]()
    var filteredSongs = [Song]()


    override func viewDidLoad() {
        super.viewDidLoad()
        self.dataManager = DataManager.getInstance()
        self.playerManager = PlayerManager.getInstance()

        playlistTransitionDelegate.screenRatio = 2.0 / 3.0

        if(self.albumID != nil) {
            self.songs = SQLiteManager.getAlbumSongs(albumID: self.albumID!)
        } else if(self.artistID != nil) {
            self.songs = SQLiteManager.getArtistSongs(artistID: self.artistID!)
        } else if (self.playlist != nil) {
            self.songs = SQLiteManager.getPlaylistSongs(playlist: self.playlist!)
        } else {
            dataManager?.songsTableViewController = self
        }

        for i in 0..<songs.count {
            songIndexMap[songs[i].id] = i
        }

        initSearchBar()
        initNavigationBar()

        if(songs.count == 0 && (!fullListOfSongs() || fullListOfSongs() && dataManager?.getFullSongsCount() == 0)){
            tableView.backgroundView = backgroundView
        }
        tableView.tableFooterView = UIView()

        tabVC = tabBarController as? TabBarController
        tabVC?.nowPlayingViewController?.delegate = self


    }



    private func shouldAutorotate() -> Bool {
        return false
    }

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

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return Util.SONG_CELL_HEIGHT
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if(isFiltering()) {
            return self.filteredSongs.count
        } else if (fullListOfSongs()) {
            return dataManager!.getFullSongsCount()
        }
        return self.songs.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cellIdentifier = "SongTableViewCell"
        guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? SongCell  else {
            fatalError("The dequeued cell is not an instance of SongCell.")
        }
        var song: Song?
        if(fullListOfSongs()) {
            if(isFiltering()){
                song = self.filteredSongs[indexPath.row]
            } else {
                song = dataManager?.getSong(index: indexPath.row)
            }
        } else {
            if(isFiltering()){
                song = self.filteredSongs[indexPath.row]
            } else {
                song = self.songs[indexPath.row]
            }
        }

        cell.setAttributes(song: song!)
        cell.delegate = self

        cell.preservesSuperviewLayoutMargins = false
        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){
        self.tableView.deselectRow(at: indexPath, animated: false)
    }



    // MARK: - Search Bar

    func updateSearchResults(for searchController: UISearchController) {
        if (!searchController.isActive) {
            hideSearchBar()
            tableView.reloadData()
        }

        if(isSearchBarEmpty()) {
            return
        }

        filterSongs(filter: searchController.searchBar.text!)
        tableView.reloadData()
    }

    private func filterSongs(filter: String) {
        if(self.albumID != nil) {
            self.filteredSongs = SQLiteManager.getAlbumSongs(albumID: self.albumID!, filter: filter)
        } else if(self.artistID != nil) {
            self.filteredSongs = SQLiteManager.getArtistSongs(artistID: self.artistID!, filter: filter)
        } else if(self.playlist != nil) {
            self.filteredSongs = SQLiteManager.getPlaylistSongs(playlist: self.playlist!, filter: filter)
        }else {
            self.filteredSongs = SQLiteManager.getSongs(filter: filter)
        }
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if searchText == "" {
            tableView.reloadData()
        }
    }


    private func initSearchBar() {
        self.searchController = UISearchController(searchResultsController:  nil)

        self.searchController.searchResultsUpdater = self
        self.searchController.delegate = self
        self.searchController.searchBar.delegate = self

        self.searchController.hidesNavigationBarDuringPresentation = false
        self.searchController.dimsBackgroundDuringPresentation = false

        searchController.searchResultsController?.view.isHidden = false
        searchController.hidesNavigationBarDuringPresentation = false

        self.extendedLayoutIncludesOpaqueBars = true
        self.definesPresentationContext = true

        searchController.searchBar.backgroundColor = UIColor.black
        UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).setTitleTextAttributes([NSAttributedStringKey.foregroundColor : UIColor.white], for: .normal)

        self.navigationItem.titleView = searchController.searchBar

        navigationItem.titleView?.isHidden = true
    }


    private func initNavigationBar() {
        searchButton.tintColor = UIColor.white
        if (fullListOfSongs()) {
            searchButton.isEnabled = false
            dataManager?.buttons.append(searchButton)
        }
        settingsButton.tintColor = UIColor.white
        self.navigationItem.title = "Songs"
        self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor : UIColor.white]
    }


    @IBAction func SearchButtonTapped(_ sender: Any) {
        showSearchBar()
    }


    private func showSearchBar(){
        self.navigationItem.titleView?.isHidden = false
        self.searchController.isActive = true

        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
            self.searchController.searchBar.becomeFirstResponder()
        }

        navigationItem.rightBarButtonItems![0].isEnabled = false
        navigationItem.rightBarButtonItems![0].image = nil
        navigationItem.rightBarButtonItems![1].isEnabled = false
        navigationItem.rightBarButtonItems![1].image = nil
    }

    private func hideSearchBar() {
        navigationItem.titleView?.isHidden = true

        navigationItem.rightBarButtonItems![0].isEnabled = true
        navigationItem.rightBarButtonItems![0].image = UIImage(named: "settings")
        navigationItem.rightBarButtonItems![1].isEnabled = true
        navigationItem.rightBarButtonItems![1].image = UIImage(named: "search")

    }

    func isFiltering() -> Bool {
        if(searchController == nil){
            return false
        }
        return searchController.isActive && !isSearchBarEmpty()
    }

    private func isSearchBarEmpty() -> Bool {
        return searchController.searchBar.text?.isEmpty ?? true
    }

    private func fullListOfSongs() -> Bool {
        return self.playlist == nil && self.albumID == nil && self.artistID == nil
    }

}

Answer 1

这在我测试的时候奏效了。我相信问题在SongsTableViewController：self.definesPresentationContext = false中。这应该是推视图控制器的true。(见docs 这里)

对于SongsTableViewController (推送视图控制器)，添加以下内容：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.definesPresentationContext = true
}

并将其添加到AlbumsCollectionViewController (初始视图控制器)：

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    self.definesPresentationContext = false
}

Answer 2

当您在SongsTableViewController上时，AlbumsCollectionViewController不在窗口层次结构中。

我能理解的是，您正在从showSearchBar调用AlbumsCollectionViewController的SongsTableViewController方法。由于您从AlbumsCollectionViewController导航到SongsTableViewController，所以您的AlbumsCollectionViewController不在窗口层次结构中，因此无法显示搜索控制器。

要修复，请尝试在SongsTableViewController中添加一个单独的搜索栏控制器，就像您以前在AlbumsCollectionViewController中所做的那样。

或者，您可以创建一个独立的视图控制器，实现搜索功能，然后将其从两个控制器中呈现出来。