swift - UISearchResultsUpdating 不根据 searchBar 文本过滤 collectionView

Question

我正在尝试根据 searchBar 文本输入过滤 collectionView。我能够在 textDidChange 和 updateSearchResults 函数调用上使用数据库中的所有用户加载和填充 UISearchResultsUpdating 类的 collectionView，但 collectionView 不会根据 searchBar 输入进行过滤(它始终显示数据库中的所有用户 - 即使在文本输入上) 。我认为棘手的部分是我有一个 collectionView(menuBar 类)，它委托(delegate)给其他 2 个 collectionView。这些 collectionView 中的每一个都有不同的 searchBar 和 searchController。请参阅随附的屏幕截图和代码以供引用。提前致谢!

//searchVC 与两个 searchControllers

class SearchVC: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, UISearchControllerDelegate, UISearchBarDelegate {

    var users = [CurrentTraveler]()
    var isSearching = false
    var filteredData = [CurrentTraveler]()

    var peopleResultsViewController: SearchPeopleResultsVC?

    var filtered:[String] = []
    var searchActive : Bool = false
    var searchPeopleController: UISearchController?

    let cellId1 = "cellId1"
    let cellId2 = "cellId2"

    override func viewDidLoad() {
        super.viewDidLoad()         
        setupSearchBar()
        setupCollectionView()
    }

    func setupSearchBar() {
        // sets up searchBar for first collectionView...
    }

    func setupCollectionView() {
        contentCollectionView.dataSource = self
        contentCollectionView.delegate = self
        contentCollectionView.register(SearchPeopleCollectionView.self, forCellWithReuseIdentifier: cellId2)
    }

    func scrollToMenuIndex(menuIndex: Int) {
        let indexPath = IndexPath(item: menuIndex, section: 0)
        contentCollectionView.scrollToItem(at: indexPath, at: UICollectionViewScrollPosition(), animated: true)

        if indexPath.item == 1 {
            searchPeopleController?.delegate = self
            searchPeopleController?.searchBar.delegate = self

            peopleResultsViewController = SearchPeopleResultsVC()

            searchPeopleController = UISearchController(searchResultsController: peopleResultsViewController)
            searchPeopleController?.searchResultsUpdater = peopleResultsViewController

            navigationItem.titleView = searchPeopleController?.searchBar
        }

        if indexPath.item == 0 {
            // sets up searchController for first collectionView search
        }
    }

//menubar collectionView
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 2
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId1", for: indexPath) 

        if indexPath.item == 0 {
            // set up first collectionView in menubar...
        }

        if indexPath.item == 1 {
            let usersCell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId2", for: indexPath) as! SearchPeopleCollectionView
            usersCell.searchVC = self
            return usersCell
        }
        return cell
    }

    var filterString = "" {
        didSet {
            guard filterString != oldValue else { return }

            if filterString.isEmpty {
                filteredData = users
            }
            else {
                filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
            }
            peopleResultsViewController?.collectionView.reloadData()
        }
    }

    func updateSearchResults(for searchPeopleController: UISearchController) {
        filterString = searchPeopleController.searchBar.text ?? ""

        if filterString.isEmpty {
            filteredData = users
        }
        else {
            filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
        }
        peopleResultsViewController?.collectionView.reloadData()
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
      // should I do anything here...?  
    }

}

//UISearchResultsUpdating 类

class SearchPeopleResultsVC : UIViewController, UISearchResultsUpdating, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UISearchBarDelegate {

    let cellId = "cellId"

    var users = [CurrentTraveler]()
    var filteredData = [CurrentTraveler]()
    var isSearching = false
    var searchVC: SearchVC?
    var peopleResultsViewController: SearchPeopleResultsVC?
    var searchController: UISearchController?
    var searchPeopleCollectionView: SearchPeopleCollectionView?
    var filtered:[String] = []
    var searchActive : Bool = false

    let searchPeopleController = UISearchController(searchResultsController: nil)

    lazy var collectionView: UICollectionView = {
        cv.dataSource = self
        cv.delegate = self
        return cv
    }()

    override func viewDidLoad() {
        collectionView.delegate = self
        collectionView.dataSource = self

        fetchTravelingUserCell()
    }

    func fetchTravelingUserCell() {
        Database.database().reference().child("users").observe(.childAdded, with: { (snapshot) in

            if let dictionary = snapshot.value as? [String: AnyObject] {
                let user = CurrentTraveler(dictionary: dictionary)
                self.users.append(user)

                DispatchQueue.main.async(execute: {
                    self.collectionView.reloadData()
                })
            }
        }, withCancel: nil)
    }

    var filterString = "" {
        didSet {
            // Return if the filter string hasn't changed.
            guard filterString != oldValue else { return }

            if filterString.isEmpty {
                filteredData = users
            }
            else {
                filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
            }
            collectionView.reloadData()
        }
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if searchPeopleController.isActive && searchPeopleController.searchBar.text != "" {
            return filteredData.count
        }
        return users.count
    }


    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellId", for: indexPath) as? BaseGlobalSearchUser else { fatalError("Expected to display a `DataItemCollectionViewCell`.") }

        if searchPeopleController.isActive && searchPeopleController.searchBar.text != "" {
            cell.currentTraveler = filteredData[indexPath.item]
        } else {
            cell.currentTraveler = users[indexPath.item]
        }
        return cell
    }

    func updateSearchResults(for searchPeopleController: UISearchController) {
        filterString = searchPeopleController.searchBar.text ?? ""
// does print what user types in the searchBar        
print(filterString)

        if filterString.isEmpty {
            filteredData = users
        }
        else {
            filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
        }
        peopleResultsViewController?.collectionView.reloadData()
    }

    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        if filterString.isEmpty {
            filteredData = users
        }
        else {
            filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
        }
        self.collectionView.reloadData()
    }

}

//数据模型类

class CurrentTraveler: SafeJsonObject {

    var name: String?
    var profileImageUrl: String?
    var travelingPlace: String?

    init(dictionary: [String: AnyObject]) {
        super.init()

        self.name = dictionary["name"] as? String
        self.profileImageUrl = dictionary["profileImageUrl"] as? String
        self.travelingPlace = dictionary["users/uid/Places"] as? String
        setValuesForKeys(dictionary)
    }
}

Answer 1

可能您的filteredString为空。所以你没有获得值(value)。

所以尝试如下:

func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
    if filterString.isEmpty {
        filterString = searchText
    }
    if filterString.isEmpty {
        filteredData = users
    } else {
        filteredData = users.filter { ($0.name?.localizedStandardContains(filterString))! }
    }
    self.collectionView.reloadData()
}