swift - 将数据从 MKAnnotationView 传递到 UICollectionViewController

Question

我有一个 UICollectionViewController，它有一个标题单元格，应该在 map 上显示注释。每个注释都是一个具有关联信息的企业，我想在标题下方的单元格(显示 map 的位置)中显示该企业信息的列表

现在我可以正确加载注释并将注释添加到我的标题单元格中。但我希望能够做的实际上是让 CollectionView 重新加载适当的数据，具体取决于用户在 map 标题中单击的注释。

这是我的标题单元格的代码，我在其中加载 MKMapView 并添加必要的方法来添加注释。

class MapHeaderCell: UICollectionViewCell, MKMapViewDelegate {

    let mapView: MKMapView = {
        let map = MKMapView()
        map.mapType = .standard
        map.isZoomEnabled = true
        map.isScrollEnabled = true
        return map
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .green

        addSubview(mapView)
        mapView.anchor(top: topAnchor, left: leftAnchor, bottom: bottomAnchor, right: rightAnchor, paddingTop: 0, paddingLeft: 0, paddingBottom: 0, paddingRight: 0, width: 0, height: 0)

        guard let latitude = UserDefaultConstants().latitude, let longitude = UserDefaultConstants().longitude  else {
            return
        }

        let coordinate = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
        let region = MKCoordinateRegion(center: coordinate, span:  MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))
        mapView.setRegion(region, animated: false)
    }

    func addAnnotations(businesses: [Business]) {
        for business in businesses {
            let annotation = MKPointAnnotation()
            annotation.title = business.name
            annotation.coordinate = CLLocationCoordinate2D(latitude: business.latitude, longitude: business.longitude)
            mapView.addAnnotation(annotation)
        }
    }

    //adds annotation to view.
    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        guard annotation is MKPointAnnotation else { return nil }
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: annotationId)

        if annotationView == nil {
            annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: annotationId)
            annotationView!.canShowCallout = true
        } else {
            annotationView!.annotation = annotation
        }
        return annotationView
    }
}

在另一个类中，我实际上加载了本地企业的数据，然后填充 map 。

class MapCollectionVewController: ListCollectionViewControllerBase {

var coupons = [Coupon]()
var businesses = [Business]()

override func viewDidLoad() {
    super.viewDidLoad()

    collectionView?.backgroundColor = .white
    collectionView?.register(CouponCell.self, forCellWithReuseIdentifier: listCellId)
    collectionView?.register(MapHeaderCell.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: mapHeaderId)

    getLocalBusinesses()
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize { 
    return CGSize(width: view.frame.width, height: 200)

}

//THIS IS WHERE I ADD ANNOTATIONS TO MAP
override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

    let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: mapHeaderId, for: indexPath) as! MapHeaderCell
    header.addAnnotations(businesses: businesses)
    return header
}

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

override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: listCellId, for: indexPath) as! CouponCell
    cell.coupon = coupons[indexPath.item]
    cell.hideFavoritesButton()
    return cell
}

fileprivate func getLocalBusinesses() {
    guard let latitude = UserDefaultConstants().latitude, let longitude = UserDefaultConstants().longitude else {
        print("No latitude/longitude value stored for user")
        return
    }

    let url = ConfigKeys.apiBaseURI + "business/nearby"
    let params = ["latitude": latitude, "longitude": longitude]

    let apiController = APIController(email: UserDefaultConstants().userEmail, token: UserDefaultConstants().userToken)
    apiController.makeRequest(type: .get, url: url, parameters: params) { (success, error, data) in
        if !success {
            print("error with request: ", error ?? "in getLocalBusiness")
        }

        guard let data = data else {return}
        guard let resultsArray = data["result"] as? [[String : Any]] else {return}

        for result in resultsArray {
            let business = Business(data: result)
            self.businesses.append(business)
        }

        self.collectionView?.reloadData()
    }
}
}

所以重申一下:我需要能够根据用户单击的注释在 map View 下方的 Collection View 中加载业务数据。我在这里阅读了一些引导我的解决方案，但无法解决这个问题。

Answer 1

找到了我需要的解决方案。发布以防万一有人也需要这个。有点长，但这在大多数情况下应该有用。

创建此协议(protocol):

protocol MapHeaderCellDelgate {
    func didSelectBusiness(id: Int)
}

在 MapHeaderCell 中创建一个作为委托(delegate)的变量。在 MKMapViewDelegate 的 DidSelect 委托(delegate)方法中，只需传递任何 View Controller 中所需的数据。

var delegate: MapHeaderCellDelgate?

func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {

        if let annotation = view.annotation as? BusinessAnnotation {
            print("Your annotation title: \(annotation.businessId)");
            guard let businessId = annotation.businessId else {return}
            delegate?.didSelectBusiness(id: businessId)
        }
    }

在我的 View Controller 中，我首先使collectionview符合创建的协议(protocol)(MapHeaderCellDelegate)

class MapCollectionVewController: ListCollectionViewControllerBase, MapHeaderCellDelgate 

在 viewForSupplementaryElementOfKind 方法中，确保将标题单元格委托(delegate)设置为 self

override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

    let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: mapHeaderId, for: indexPath) as! MapHeaderCell

    header.delegate = self
    header.addAnnotations(businesses: businesses)
    return header
}

最后，在协议(protocol)方法中，您现在可以使用刚刚传递的数据来执行您想要的操作。完成数据处理后，请务必重新加载 collectionView，以便 View 更新并显示您需要显示的任何内容

func didSelectBusiness(id: Int) {
    someFunction(id: id)
}

func someFunction(id: Int) {
    //DO STUFF
    //...
    collectionView?.reloadData()
}