在MKMapView中绘制矩形

Question

我正在尝试在MKMapView中绘制一个红色矩形。我看到了地图，但没有看到矩形。我的代码：

public override void ViewDidLoad()
{
    base.ViewDidLoad();

    var areaMapView = new AreaMapView();

    areaMapView.SetTarget(45.5399396, -73.6534612);

    areaMapView.AddZone(new List<Geolocation>()
    {
        new Geolocation() { Latitude = 25.774, Longitude = -80.190},
        new Geolocation() { Latitude = 18.466, Longitude = -66.118},
        new Geolocation() { Latitude = 32.321, Longitude = -64.757},
        new Geolocation() { Latitude = 25.774, Longitude = -80.190},
    });

    View = areaMapView;
}

public class AreaMapView : MKMapView
{
    public AreaMapView() : base(UIScreen.MainScreen.Bounds)
    {
        this.ShowsUserLocation = true;
        this.MapType = MKMapType.Satellite;
    }

    public void SetTarget(double longitude, double latitude)
    {
        this.AddAnnotations(new MKPointAnnotation()
        {
            Title = "Target",
            Coordinate = new CLLocationCoordinate2D(longitude, latitude)
        });
    }

    public void AddZone(List<Geolocation> longitudeAndLatitudePoints)
    {
        var coords = new CLLocationCoordinate2D[longitudeAndLatitudePoints.Count];

        for (int i = 0; i < longitudeAndLatitudePoints.Count; i++)
        {
            double longitude = longitudeAndLatitudePoints[i].Longitude;
            double latitude = longitudeAndLatitudePoints[i].Latitude;

            coords[i] = new CLLocationCoordinate2D(longitude, latitude);
        }

        this.AddOverlay(MKPolyline.FromCoordinates(coords));
    }
}

Answer 1

我认为您应该使用 MKPolygon 和 MKPolygonRenderer 来添加矩形。

请参阅此处：https://developer.xamarin.com/recipes/ios/content_controls/map_view/add_an_overlay_to_a_map/

此处示例：https://github.com/xamarin/recipes/tree/master/ios/content_controls/map_view/add_an_overlay_to_a_map

按照示例并替换代码

 mapView.OverlayRenderer = (m, o) =>
        {
            if (circleRenderer == null)
            {
                circleRenderer = new MKCircleRenderer(o as MKCircle);
                circleRenderer.FillColor = UIColor.Purple;
                circleRenderer.Alpha = 0.5f;
            }
            return circleRenderer;
        };

        circleOverlay = MKCircle.Circle(coords, 400);
        mapView.AddOverlay(circleOverlay);

通过

 mapView.OverlayRenderer = (m, o) =>
        {
            if (polygonRenderer == null)
            {
                polygonRenderer = new MKPolygonRenderer(o as MKPolygon);
                polygonRenderer.FillColor = UIColor.Red;
                polygonRenderer.StrokeColor = UIColor.Black;
                polygonRenderer.Alpha = 0.5f;
            }
            return polygonRenderer;
        };


        var coord = new CLLocationCoordinate2D[4];

        coord[0] = new CLLocationCoordinate2D(29.976111, 31.132778);
        coord[1] = new CLLocationCoordinate2D(29.976111, 31.032778);
        coord[2] = new CLLocationCoordinate2D(29.876111, 31.032778);
        coord[3] = new CLLocationCoordinate2D(29.876111, 31.132778);

        mapView.AddOverlay(MKPolygon.FromCoordinates(coord));

这是结果