如果 pin 属性等于一个值，如何更改 xamarin.forms.maps 上的 pin 图标 - android

如何解决如果 pin 属性等于一个值，如何更改 xamarin.forms.maps 上的 pin 图标 - android

我有 CustomPin 个对象类：

using Xamarin.Forms.Maps;

namespace Customrenderer
{
    public class CustomPin : Pin
    {
        public string Name { get; set; }
        public string Url { get; set; }
        public int CodeNum { get; set; }
        public int AlertLevel { get; set; }
    }
}

我的 CustomMapRenderer.cs 代码是：

using System;
using System.Collections.Generic;
using Android.Content;
using Android.Gms.Maps;
using Android.Gms.Maps.Model;
using Android.Widget;
using Customrenderer;
using Customrenderer.Droid;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Maps.Android;

[assembly: ExportRenderer(typeof(CustomMap),typeof(CustomMapRenderer))]
namespace Customrenderer.Droid
{
    public class CustomMapRenderer : MapRenderer,GoogleMap.IInfoWindowAdapter
    {
        List<CustomPin> customPins;

        public CustomMapRenderer(Context context) : base(context)
        {
        }

        protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Map> e)
        {
            base.OnElementChanged(e);

            if (e.OldElement != null)
            {
                NativeMap.InfoWindowClick -= OnInfoWindowClick;
            }

            if (e.NewElement != null)
            {
                var formsMap = (CustomMap)e.NewElement;
                customPins = formsMap.CustomPins;
            }
        }

        protected override void OnMapReady(GoogleMap map)
        {
            base.OnMapReady(map);

            NativeMap.InfoWindowClick += OnInfoWindowClick;
            NativeMap.SetInfoWindowAdapter(this);
        }

        protected override MarkerOptions CreateMarker(Pin pin)
        {
            var marker = new MarkerOptions();
            marker.SetPosition(new LatLng(pin.Position.Latitude,pin.Position.Longitude));
            marker.SetTitle(pin.Label);
            marker.SetSnippet(pin.Address);
            marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.yellow));
            return marker;
        }

        void OnInfoWindowClick(object sender,GoogleMap.InfoWindowClickEventArgs e)
        {
            var customPin = GetCustomPin(e.Marker);
            if (customPin == null)
            {
                throw new Exception("Custom pin not found");
            }

            if (!string.IsNullOrWhiteSpace(customPin.Url))
            {
                var url = Android.Net.Uri.Parse(customPin.Url);
                var intent = new Intent(Intent.ActionView,url);
                intent.AddFlags(ActivityFlags.NewTask);
                Android.App.Application.Context.StartActivity(intent);
            }
        }

        public Android.Views.View GetInfoContents(Marker marker)
        {
            var inflater = Android.App.Application.Context.GetSystemService(Context.LayoutInflaterService) as Android.Views.LayoutInflater;
            if (inflater != null)
            {
                Android.Views.View view;

                var customPin = GetCustomPin(marker);
                if (customPin == null)
                {
                    throw new Exception("Custom pin not found");
                }

                if (customPin.Name.Equals("Xamarin"))
                {
                    view = inflater.Inflate(Resource.Layout.XamarinMapInfoWindow,null);
                }
                else
                {
                    view = inflater.Inflate(Resource.Layout.MapInfoWindow,null);
                }

                CustomPin pin = GetCustomPin(marker);

                int CodeNum = pin.CodeNum;          
                int AlertLevel = pin.AlertLevel;

                var infoTitle = view.FindViewById<TextView>(Resource.Id.InfoWindowTitle);
                var infoSubtitle = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle);
                var infoSubtitle2 = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle2);
                var infoSubtitle3 = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle3);

                if (infoTitle != null)
                {
                    infoTitle.Text = marker.Title;
                }
                if (infoSubtitle != null)
                {
                    infoSubtitle.Text = marker.Snippet;
                }
                if (infoSubtitle2 != null)
                {
                    infoSubtitle2.Text = "Тревога: (1-4): " + AlertLevel;
                }
                if (infoSubtitle3 != null)
                {
                    infoSubtitle3.Text = "Номер на станция: " + CodeNum;
                }

                return view;
            }
            return null;
        }

        public Android.Views.View GetInfoWindow(Marker marker)
        {
            return null;
        }

        CustomPin GetCustomPin(Marker annotation)
        {
            var position = new Position(annotation.Position.Latitude,annotation.Position.Longitude);

            //db connection and query
            foreach (var pin in customPins)
            {
                if (pin.Position == position)
                {
                    return pin;
                }
            }
            return null;
        }
    }
}

在这种方法中，我更改了所有引脚的图标：

protected override MarkerOptions CreateMarker(Pin pin)
    {
        var marker = new MarkerOptions();
        marker.SetPosition(new LatLng(pin.Position.Latitude,pin.Position.Longitude));
        marker.SetTitle(pin.Label);
        marker.SetSnippet(pin.Address);
        marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.yellow));
        return marker;
    }

我想在 MarkerOptions 内检查：

If (CustomPin.AlertLevel == 1){ 
marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.yellow));
} else if (CustomPin.AlertLevel == 2) {
marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.green));
}

当我将 protected override MarkerOptions CreateMarker(Pin pin) 替换为：

protected override MarkerOptions CreateMarker(CustomPin pin)

CreateMarker alert me with this error: 

 Error CS0115: 'CustomMapRenderer.CreateMarker(CustomPin)': no suitable method found to override (CS0115) (Customrenderer.Droid)

如何查看我的CustomPin.AlertLevel的状态并更改标记的图标？

解决方法

在 CreateMarker 中，找到与当前引脚匹配的自定义引脚并以此为基础进行逻辑

var custom  = customPins.Where(x => x.Label == pin.Label && x.Address == pin.Address).FirstOrDefault();

if (custom != null)  {
  // set the icon here based on the values of custom
}