尝试在Xamarin.Forms.iOS的CustomMap上添加多个customPin

Question

XAML：

       <local:CustomMap x:Name="mymap" MapType="Street"  IsShowingUser="true"/>

码：

        var pin = new CustomPin ();
        pin.MapPin.Label = "Test";
        pin.MapPin.Position = new Position(32, 10);
        pin.MapPin.Label = "1";
        pin.MapPin.Address = "394 Pacific Ave, San Francisco CA";
        pin.Id = "Xamarin";

        pin = new CustomPin ();
        pin.MapPin.Label = "Test2";
        pin.MapPin.Position = new Position(33, 10);
        pin.MapPin.Label = "2";
        pin.MapPin.Address = "394 Pacific Ave, San Francisco CA";
        pin.Id = "Xamarin";

        mymap.CustomPins = new List<CustomPin> { pin };
        mymap.Pins.Add (pin.MapPin);

使用此代码，我在地图上只得到一个销，该销是我创建的最新销，因此在本例中为“ Test2”。 如何调整代码，以便可以添加多个引脚？

CustomMap：

public class CustomMap : Map
{
    public MapContentType ContentType { get; set; }
    public double CircleRadius { get; set; }

    public List<Position> Positions { get; set; }

    public List<CustomPin> CustomPins { get; set;}

    public CustomCircle Circle { get; set; }

    public CustomMap()
    {
        this.ContentType = MapContentType.Normal;
        this.CircleRadius = 500;
        this.Positions = new List<Position> ();
    }

}

CustomPin：

public class CustomPin
{
        public CustomPin() {
            MapPin = new Pin();
        }
        public string Id { get; set; }
        public EventHandler Url { get; set; }
        public Pin MapPin { get; set; }
}

自定义渲染器：

 public class CustomMapRenderer : MapRenderer
{
    MKPolylineRenderer polylineRenderer;

    UIView customPinView;

    List<CustomPin> customPins;

    MKCircleRenderer circleRenderer;

    protected override void OnElementChanged (ElementChangedEventArgs<View> e)
    {
        base.OnElementChanged (e);

        if (e.OldElement != null) {
            var nativeMap = Control as MKMapView;
            nativeMap.OverlayRenderer = null;

            nativeMap.GetViewForAnnotation = null;

            nativeMap.GetViewForAnnotation = null;
            nativeMap.DidSelectAnnotationView -= OnDidSelectAnnotationView;
            nativeMap.DidDeselectAnnotationView -= OnDidDeselectAnnotationView;




        }

        if (e.NewElement != null) {
            var formsMap = (CustomMap)e.NewElement;
            var nativeMap = Control as MKMapView;


            customPins = formsMap.CustomPins;
            nativeMap.GetViewForAnnotation = GetViewForAnnotation;


            nativeMap.GetViewForAnnotation = GetViewForAnnotation;
            nativeMap.DidSelectAnnotationView += OnDidSelectAnnotationView;
            nativeMap.DidDeselectAnnotationView += OnDidDeselectAnnotationView;



            nativeMap.OverlayRenderer = GetOverlayRenderer;

            CLLocationCoordinate2D[] coords = new CLLocationCoordinate2D[formsMap.Positions.Count];

            int index = 0;
            foreach (var position in formsMap.Positions) {
                coords [index] = new CLLocationCoordinate2D (position.Latitude, position.Longitude);
                index++;
            }

            var routeOverlay = MKPolyline.FromCoordinates (coords);
            nativeMap.AddOverlay (routeOverlay);
        }


    }

    MKOverlayRenderer GetOverlayRenderer (MKMapView mapView, IMKOverlay overlay)
    {
        if (polylineRenderer == null ) {
            polylineRenderer = new MKPolylineRenderer (overlay as MKPolyline);
            polylineRenderer.FillColor = UIColor.Blue;
            polylineRenderer.StrokeColor = UIColor.Black;
            polylineRenderer.LineWidth = 10;
            polylineRenderer.Alpha = 0.4f;

        }
        return polylineRenderer;

    }

    string pId = "PinAnnotation";

    MKAnnotationView GetViewForAnnotation (MKMapView mapView, IMKAnnotation annotation)
    {
        MKAnnotationView annotationView = null;

        if (annotation is MKUserLocation)
            return null;

        var anno = annotation as MKPointAnnotation;
        var customPin = GetCustomPin (anno);
        if (customPin == null) {
            throw new Exception ("Custom pin not found");
        }

        MKAnnotationView pinView = (MKPinAnnotationView)mapView.DequeueReusableAnnotation (pId);

        annotationView = mapView.DequeueReusableAnnotation (customPin.Id);
        if (annotationView == null) {
            annotationView = new CustomMKPinAnnotationView (annotation, customPin.Id);
            annotationView.Image = UIImage.FromFile ("pin.png");
            //((MKPinAnnotationView)pinView).PinColor = MKPinAnnotationColor.Green;

            annotationView.CalloutOffset = new CGPoint (0, 0);
            annotationView.LeftCalloutAccessoryView = new UIImageView (UIImage.FromFile ("monkey.png"));
            annotationView.RightCalloutAccessoryView = UIButton.FromType (UIButtonType.DetailDisclosure);
            ((CustomMKPinAnnotationView)annotationView).Id = customPin.Id;
            ((CustomMKPinAnnotationView)annotationView).Url = customPin.Url;
        }
        annotationView.CanShowCallout = true;

        return annotationView;
    }

    void OnDidSelectAnnotationView (object sender, MKAnnotationViewEventArgs e)
    {
        var customView = e.View as CustomMKPinAnnotationView;
        customPinView = new UIView ();

        if (customView.Id == "Xamarin") {
            customPinView.Frame = new CGRect (0, 0, 200, 84);
            var image = new UIImageView (new CGRect (0, 0, 200, 84));
            image.Image = UIImage.FromFile ("xamarin.png");
            customPinView.AddSubview (image);
            customPinView.Center = new CGPoint (0, -(e.View.Frame.Height + 75));
            e.View.AddSubview (customPinView);
        }
    }

    void OnDidDeselectAnnotationView (object sender, MKAnnotationViewEventArgs e)
    {
        if (!e.View.Selected) {
            customPinView.RemoveFromSuperview ();
            customPinView.Dispose ();
            customPinView = null;
        }
    }

    CustomPin GetCustomPin (MKPointAnnotation annotation)
    {
        var position = new Position (annotation.Coordinate.Latitude, annotation.Coordinate.Longitude);
        foreach (var pin in customPins) {
            if (pin.MapPin.Position == position) {
                return pin;
            }
        }
        return null;
    }




   }
}

Answer 1

您将获得一个图钉，因为您要添加一个图钉。 您需要了解一些编程基础知识，例如“更改对象的属性不会创建新对象”

尝试这个

var pin = new CustomPin ();
    pin.MapPin.Label = "Test";
    pin.MapPin.Position = new Position(32, 10);
    pin.MapPin.Label = "1";
    pin.MapPin.Address = "394 Pacific Ave, San Francisco CA";
    pin.Id = "Xamarin";

   var pin1 = new CustomPin ();
    pin1.MapPin.Label = "Test2";
    pin1.MapPin.Position = new Position(33, 10);
    pin1.MapPin.Label = "2";
    pin1.MapPin.Address = "394 Pacific Ave, San Francisco CA";
    pin1.Id = "Xamarin";

    mymap.CustomPins = new List<CustomPin> { pin,pin1 };
    mymap.Pins.Add (pin.MapPin);
    mymap.Pins.Add (pin1.MapPin);

评论中提到的您的问题的解决方案，App.Items是使用以下方法从数据库或Web服务（在我的情况下为Web服务）中填充的列表

System.Collections.Generic;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using System;

namespace App
{
    public class MapPage : ContentPage
    {
        public  CustomMap customMap1{ get; set;}
        public MapPage ()
        {
            Title ="Stores";
            Icon = "flag_map_marker4.png";


             var customMap = new CustomMap {
                MapType = MapType.Street,
                WidthRequest = App.ScreenWidth,
                HeightRequest = App.ScreenHeight
            };

            customMap.CustomPins = new List<CustomPin>();
            if (App.Items != null && App.Items.Count > 0) {
                foreach (var t in App.Items) {
                    var temp = new CustomPin () {
                        Pin = new Pin () {
                            Label = t.Name,
                            Type = PinType.Place,
                            Position = new Position (t.Lat, t.Lon),
                            Address = t.Address1
                        },
                        Url = t.Link
                    };
                    customMap.CustomPins.Add (temp);
                }
                foreach (var pin in customMap.CustomPins) {
                    customMap.Pins.Add (pin.Pin);
                }
                // dont delete below code ,they will save you if timer doesnt work .

                //var temp1 = new MapSpan(customMap.CustomPins [0].Pin.Position,
//              if(Device.OS == TargetPlatform.iOS)
//              customMap.MoveToRegion (MapSpan.FromCenterAndRadius (customMap.CustomPins [0].Pin.Position, Distance.FromMiles (0.20)));

                if(Device.OS == TargetPlatform.Android)
                customMap.MoveToRegion (MapSpan.FromCenterAndRadius (customMap.CustomPins [0].Pin.Position, Distance.FromMiles (55.0)));
                if (Device.OS == TargetPlatform.iOS) {
                    Device.StartTimer (TimeSpan.FromMilliseconds (500), () => {
                        customMap.MoveToRegion (MapSpan.FromCenterAndRadius (customMap.CustomPins [0].Pin.Position, Distance.FromMiles (55.0)));
                        return false;
                    });
                }
            }

            Content = customMap;
        }

    }


}

`只要忽略无关紧要的线！

Answer 2

Xamarin自定义地图渲染器遇到了同样的问题。 我发现问题的原因是在OnMapElementClick函数中检查mapOverlay == null 。

注释掉它，一切都适用于多个引脚。 不知道为什么会首先出现。