swift - SearchController 不显示程序化的 collectionView 单元格

Question

我正在尝试实现一个搜索 Controller 。从数组显示一切正常。现在我试图显示 MapKit 的结果，但在 collectionView 中看不到任何内容。我正在以编程方式完成所有操作，因此这可能就是我将 collectionView 调用为 resultsView 的方式。我做错了什么？

这是主视图 Controller : 导入 UIKit 导入MapKit

class LocationVC: UIViewController, MKMapViewDelegate {

    let locationManager = CLLocationManager()
    var resultSearchController:UISearchController? = nil

    let mapView : MKMapView = {
        let map = MKMapView()
        map.translatesAutoresizingMaskIntoConstraints = false
        return map
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        let window = UIWindow.init(frame: UIScreen.main.bounds)
        window.makeKeyAndVisible()

        setupBasicNavigation(title: "")
        setupLocationManager()
        setupMapView()

        mapView.delegate = self
        mapView.showsUserLocation = true

        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Cancel", style: .done, target: self, action: #selector(cancelAndGoBack))

        setupSearchController()
        searchBarSetup()


    }

    //MARK: Setting up the Search Bar
    func searchBarSetup() {
        let searchBar = resultSearchController!.searchBar
        searchBar.sizeToFit()
        searchBar.placeholder = "Search for places"
        navigationItem.titleView = resultSearchController?.searchBar

        resultSearchController?.hidesNavigationBarDuringPresentation = false
        resultSearchController?.dimsBackgroundDuringPresentation = true
        definesPresentationContext = true
    }

    //MARK: Setting up the Search Controller
    func setupSearchController() {
        let locationSearchTable = LocationSearchTable()
        resultSearchController = UISearchController(searchResultsController: locationSearchTable)
        resultSearchController?.searchResultsUpdater = locationSearchTable as UISearchResultsUpdating
        locationSearchTable.modalPresentationStyle = .currentContext
        self.present(locationSearchTable, animated: false, completion: nil)
        locationSearchTable.mapView = mapView
        //self.present(locationSearchTable, animated: false, completion: nil)
    }

    //MARK: Setting up the Map View
    func setupMapView() {
        view.addSubview(mapView)
        mapView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        mapView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        mapView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
        mapView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
    }

    //MARK: Setting up the Location Manager
    func setupLocationManager() {
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.requestWhenInUseAuthorization()
        locationManager.requestLocation()
    }

    //MARK: Sends to the back controller
    func cancelAndGoBack() {
        print("Canceled and Saved")
        self.dismiss(animated: true, completion: nil)
    }


}

//MARK: Extension to provide the delegates methods for LOcation
extension LocationVC : CLLocationManagerDelegate {
    private func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
        if status == .authorizedWhenInUse {
            locationManager.requestLocation()
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let location = locations.first {
            let span = MKCoordinateSpanMake(0.05, 0.05)
            let region = MKCoordinateRegion(center: location.coordinate, span: span)
            mapView.setRegion(region, animated: true)
        }
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("error:: \(error)")
    }
}

这是结果的 View Controller :

    import UIKit
import MapKit

class LocationSearchTable: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {

    var collectionView: UICollectionView!

    var matchingItems:[MKMapItem] = []
    var mapView: MKMapView? = nil

    override func viewDidLoad() {
        super.viewDidLoad()

        let window = UIWindow.init(frame: UIScreen.main.bounds)
        window.makeKeyAndVisible()

        setupCollectionView()
        setupBasicNavigation(title: "")


    }

    //MARK: Setup CollectionView
    func setupCollectionView() {

        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 50, left: 0, bottom: 110, right: 0)
        layout.itemSize = CGSize(width: view.frame.size.width, height: 40)

        layout.minimumLineSpacing = 1

        collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView.dataSource = self as UICollectionViewDataSource
        collectionView.delegate = self

        //collection view design
        collectionView?.backgroundColor = UIColor(r: 242, g: 240, b: 240)
        collectionView?.alwaysBounceVertical = false
        collectionView?.showsVerticalScrollIndicator = false
        collectionView?.scrollsToTop = false

        collectionView.register(LocationCell.self, forCellWithReuseIdentifier: "LocationCell")

    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return matchingItems.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "LocationCell", for: indexPath) as! LocationCell
        cell.contentView.backgroundColor = .white
        cell.layer.borderColor = UIColor(white: 0.5, alpha: 0.3).cgColor
        cell.layer.borderWidth = 0.3

        let selectedItem = matchingItems[indexPath.row].placemark
        cell.itemName.text = selectedItem.name

        return cell
    }

    //cell function to determine size
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        return CGSize(width: view.frame.width, height: 40)
    }

}

//MARK: Extension for Search Controller Delegate
extension LocationSearchTable : UISearchResultsUpdating {
    func updateSearchResults(for searchController: UISearchController) {

    }
    func updateSearchResultsForSearchController(searchController: UISearchController) {
        guard let mapView = mapView,
            let searchBarText = searchController.searchBar.text else { return }
        let request = MKLocalSearchRequest()
        request.naturalLanguageQuery = searchBarText
        request.region = mapView.region
        let search = MKLocalSearch(request: request)
        search.start { response, _ in
            guard let response = response else {
                return
            }
            self.matchingItems = response.mapItems
            self.collectionView.reloadData()
        }
    }
}

Answer 1

看来我正在使用:

func updateSearchResultsForSearchController

当我应该使用时:

func updateSearchResults(for searchController: UISearchController) {

将代码从 updateSearchResultsForSearchController 复制到 updateSearchResults 就成功了，因为这是我使用错误的正常实现。