ios - 获取注释的边界

Question

我试图找到我在 MapView 上的注释列表的边界。

我看到在 javascript 中，您可以将注释添加到层的 FeatureGroup，然后获取该组的边界。

但是，我在 Swift SDK 中找不到它。我怎样才能获得一组注释的界限？

Answer 1

您需要使用MKMapView 的.annotations 属性，并获取minX、minY、 ma​​xX 和 ma​​xY，之后您可以将这些点作为坐标返回，并根据需要添加叠加层

func getCordinatesOfRectAnnotations(annotationsArray:[MKAnnotation]) ->[CLLocationCoordinate2D]{
    let minX : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).x}).min()!
    let minY : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).y}).min()!
    let maxX : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).x}).max()!
    let maxY : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).y}).max()!

    var result : [CLLocationCoordinate2D] = []
    result.append(MKCoordinateForMapPoint(MKMapPoint(x: minX, y: minY)))
    result.append(MKCoordinateForMapPoint(MKMapPoint(x: maxX, y: minY)))
    result.append(MKCoordinateForMapPoint(MKMapPoint(x: maxX, y: maxY)))
    result.append(MKCoordinateForMapPoint(MKMapPoint(x: minX, y: maxY)))
    return result
}

完整示例代码

import UIKit
import MapKit

class ViewController: UIViewController {

    @IBOutlet weak var mapView: MKMapView!
    var moscow: [Camera] = []
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        let coordinates = [CLLocationCoordinate2D(latitude:  40.741895, longitude:  -73.989308),CLLocationCoordinate2D(latitude:  38.80495938042258, longitude: -77.0273450631467),CLLocationCoordinate2D(latitude:  40.14404110473566, longitude:  -3.487181320896525),CLLocationCoordinate2D(latitude:  41.3425986835203, longitude:  2.093873366603475),CLLocationCoordinate2D(latitude:  -15.70239476628682, longitude:  27.486982547083358)]

        for (index,coordinate) in coordinates.enumerated() {
            let annotation = MKPointAnnotation()
            annotation.coordinate = coordinate
            annotation.title = "coordinate\(index)"
            self.mapView.addAnnotation(annotation)
        }

        self.mapView.delegate = self

        let overlay = MKPolygon(coordinates: self.getCordinatesOfRectAnnotations(annotationsArray: self.mapView.annotations), count: self.getCordinatesOfRectAnnotations(annotationsArray: self.mapView.annotations).count)
        self.mapView.add(overlay)
    }

    func getCordinatesOfRectAnnotations(annotationsArray:[MKAnnotation]) ->[CLLocationCoordinate2D]{
       let minX : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).x}).min()!
       let minY : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).y}).min()!
       let maxX : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).x}).max()!
       let maxY : Double = annotationsArray.map({MKMapPointForCoordinate($0.coordinate).y}).max()!

       var result : [CLLocationCoordinate2D] = []
       result.append(MKCoordinateForMapPoint(MKMapPoint(x: minX, y: minY)))
       result.append(MKCoordinateForMapPoint(MKMapPoint(x: maxX, y: minY)))
       result.append(MKCoordinateForMapPoint(MKMapPoint(x: maxX, y: maxY)))
       result.append(MKCoordinateForMapPoint(MKMapPoint(x: minX, y: maxY)))
       return result
    }

}

extension ViewController : MKMapViewDelegate
{
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let renderer = MKPolygonRenderer(overlay: overlay)
        renderer.lineWidth = 1
        renderer.strokeColor = UIColor.red
        return renderer
    }

    // Called when the annotation was added
    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        if annotation is MKUserLocation {
            return nil
        }

        let reuseId = "pin"
        var pinView = mapView.dequeueReusableAnnotationView(withIdentifier: reuseId) as? MKPinAnnotationView
        if pinView == nil {
            pinView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
            pinView?.animatesDrop = true
            pinView?.canShowCallout = true
            pinView?.isDraggable = true
            pinView?.pinColor = .purple

            let rightButton: AnyObject! = UIButton(type: UIButtonType.detailDisclosure)
            pinView?.rightCalloutAccessoryView = rightButton as? UIView
        } else {
            pinView?.annotation = annotation
        }

        return pinView
    }

}

结果