将数据从 MKAnnotationView 传递到 UICollectionViewController

Question

我有一个 UICollectionViewController，它有一个标题单元格，应该在地图上显示注释。每个注释都是一个具有相关信息的企业，我想在标题下方的单元格中显示该企业信息的列表（显示地图的位置）

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。但我想要做的实际上是让collectionview重新加载适当的数据，具体取决于用户在地图标题中单击的注释。

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，然后填充地图。

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地图视图下方的集合视图中加载业务数据。我在这里阅读了一些解决方案，这些解决方案让我很受鼓舞，但一直无法解决这个问题。

Answer 1

找到了我需要的解决方案。发布以防有人也需要。有点冗长，但在大多数情况下这应该可以解决问题。

创建此协议：

protocol MapHeaderCellDelgate {
    func didSelectBusiness(id: Int)
}

在 MapHeaderCell 中创建一个作为委托的变量。在 MKMapViewDelegate 的 DidSelect 委托方法中，只需在任何视图控制器中传递您需要的数据。

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)
        }
    }

在我的视图控制器中，我首先将集合视图与创建的协议 (MapHeaderCellDelegate) 保持一致

class MapCollectionVewController: ListCollectionViewControllerBase, MapHeaderCellDelgate 

在 viewForSupplementaryElementOfKind 方法中确保将标题单元格委托设置为 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，在协议方法中，您现在可以使用刚刚传递的数据来做任何您想做的事情。确保在处理完数据后重新加载 collectionView，以便视图更新为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()
}