android 自定义引脚查询上的 Xamarin 地图

如何解决android 自定义引脚查询上的 Xamarin 地图

我正在开发一个 xamarin 表单应用程序，目前使用适用于 Android 的 xamarin 表单地图跟踪我的位置，并且根据我与放置在地图上的自定义图钉的接近程度，大小会根据我的接近程度而改变。基本上，如果在几米内，图标是 32x32，更远的是 24x24。我创建了一个自定义地图渲染器，它可以从 JSON 文件中放置我的图钉，这没问题。当我的地图表单页面在我的模拟器和实际的 android 设备中加载时，这些方法会运行并根据我的位置获取我的接近度，并适当地改变地图图钉的大小。但是，这在我四处走动时不起作用。出于某种原因，除非我调用 Content=customMap，否则当我的位置更改时，我重写的 CreateMarker 方法不会触发。这样做只会导致我的地图一遍又一遍地加载，基本上不会工作。我的关于页面中有一个名为 UpdateMap3() 的方法，该方法在用户位置更改时调用。但是，如前所述，当应用程序运行时，当我靠近图钉时，我无法让图钉更新它们的大小。

我在下面包含了我的表单页面代码，在下面包含了标记，最后在下面包含了我的地图渲染器。任何帮助将不胜感激。谢谢

    using System;
using System.IO;
using System.Reflection;
using Xamarin.Forms;
using Newtonsoft.Json;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading.Tasks;
using Xamarin.Forms.Maps;
using Xamarin.Essentials;
using distance = Xamarin.Forms.Maps.distance;
using Google.Protobuf.WellKNownTypes;
using static Google.Protobuf.Reflection.FieldDescriptorProto.Types;

namespace MAPS.Views
{
    public partial class AboutPage : ContentPage
    {
        IlocationUpdateService loc;
     
        public AboutPage()
        {
            InitializeComponent();
          //  Task.Delay(2000);
          UpdateMap();
        }
        async void OnActionSheetCancelDeleteClicked()
        {
            bool answer = await displayAlert("Location Request","Please enable location services to use this app","Settings","Cancel");
            if (answer == true)
            {
                DependencyService.Get<ILocSettings>().OpenSettings();
            }
        }
        protected override void OnAppearing()
        {
            base.OnAppearing();
            bool gpsstat = DependencyService.Get<ILocSettings>().isGpsAvailable();
            if (gpsstat == false)
            {
                OnActionSheetCancelDeleteClicked();
            }

            loc = DependencyService.Get<IlocationUpdateService>();

            loc.LocationChanged += (object sender,ILocationEventArgs args) =>
              {

                     String lat1 = args.Latitude.ToString();
                    String lng1 = args.Longitude.ToString();
                  //String lat1 = "55.099300";
                  // String lng1 = "-8.279740";
                  UpdateMap3(lat1,lng1); ;
              };
            loc.GetUsedLocation();
  
        }
        
        protected override void Ondisappearing()
        {
            base.Ondisappearing();
            loc = null;

        }
        List<Place> placesList = new List<Place>();
        private async void UpdateMap()
        {
            var assembly = IntrospectionExtensions.GetTypeInfo(typeof(AboutPage)).Assembly;
                Stream stream = assembly.GetManifestResourceStream("MAPS.Places.json");
                string text = string.Empty;
                using (var reader = new StreamReader(stream))
                {
                    text = reader.ReadToEnd();
                }
                var resultObject = JsonConvert.DeserializeObject<Places>(text);
                var request = new Xamarin.Essentials.GeolocationRequest(GeolocationAccuracy.Best,TimeSpan.FromSeconds(30));
                var location = await Geolocation.GetLocationAsync(request);
            CustomMap customMap = new CustomMap()
            {
                IsShowingUser = true

            };
            customMap.CustomPins = new List<CustomPin>(); // put this before the foreach

            foreach (var place in resultObject.results)
            {
                Location location1 = new Location(place.geometry.location.lat,place.geometry.location.lng);
              //  string color = getdist(location1,location);
              string  color = "purple";
                if (color == "purple")
                {
                    CustomPin pin = new CustomPin()
                    {

                        Type = PinType.Place,Position = new Position(place.geometry.location.lat,place.geometry.location.lng),Label = place.id,Address = place.vicinity+"*",Name = "Xamarin",icon = "icon.png",Url = "http://xamarin.com/about/"
                    };

                    customMap.Pins.Add(pin);
                    
                }
                else
                {
                    CustomPin pin = new CustomPin()
                    {

                        Type = PinType.Place,Address = place.vicinity,icon = "pin.png",Url = "http://xamarin.com/about/"
                    };

                    customMap.Pins.Add(pin);
                  
                }
            }
                customMap.MovetoRegion(MapSpan.FromCenterandRadius(new Position(location.Latitude,location.Longitude),distance.FromKilometers(0.15))); ;
            Content = customMap;
  }
        public string getdist(Location loc,Xamarin.Essentials.Location currentLoc)
        {
            string color = "red";
            //  bool geo = false;
            double latEnd = loc.lat;
            double lngEnd = loc.lng;
            ///  Position(currentLoc.lat,currentLoc.lng);
            double dist = currentLoc.Calculatedistance(latEnd,lngEnd,distanceUnits.Kilometers);
            if (dist < 0.05) //5m distance
            {

                color = "purple";



            }
            else
            {
                color = "red";
            }
            return color;
        }
        public void getNewPins()
        {
            InitializeComponent();

        }
 public void getPin()
        {
            var pr = new PopUp();
        }


        private async void UpdateMap3(String lat,String lng)
        {
            var assembly = IntrospectionExtensions.GetTypeInfo(typeof(AboutPage)).Assembly;
            Stream stream = assembly.GetManifestResourceStream("MAPS.Places.json");
            string text = string.Empty;
            using (var reader = new StreamReader(stream))
            {
                text = reader.ReadToEnd();
            }
            var resultObject = JsonConvert.DeserializeObject<Places>(text);
        
            CustomMap customMap = new CustomMap()
            {
                IsShowingUser = true

            };

            customMap.CustomPins = new List<CustomPin>(); // put this before the foreach

            foreach (var place in resultObject.results)
            {
                Location location1 = new Location(place.geometry.location.lat,place.geometry.location.lng);
                Xamarin.Essentials.Location location = new Xamarin.Essentials.Location(Convert.Todouble(lat),Convert.Todouble(lng));
                string color = getdist(location1,location);

                if (color == "purple")
                {
                    CustomPin pin2 = new CustomPin()
                    {

                        Type = PinType.Place,Url = "http://xamarin.com/about/"
                    };
                    customMap.CustomPins = new List<CustomPin> {pin2};                  
                    customMap.Pins.Add(pin2);
    
                }
                else
                {
                    CustomPin pin2 = new CustomPin()
                    {

                        Type = PinType.Place,Url = "http://xamarin.com/about/"
                    };
                    customMap.CustomPins = new List<CustomPin> { pin2 };
                    customMap.Pins.Add(pin2);
                  //  Content.IsEnabled = true;
                    // customMap.CustomPins.Remove(pin);
                }
            }
            //   customMap.Pins.Clear();


            //   customMap.MovetoRegion(MapSpan.FromCenterandRadius(new Position(Convert.Todouble(lat),Convert.Todouble(lng)),distance.FromKilometers(0.15))); ;
          //  Content = customMap;

           // customMap.Pins.Add(pins);
        }
  }
    }

下面是我的表单页面标记。

  <?xml version="1.0" encoding="UTF-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:MAPS;assembly=MAPS"
             x:Class="MAPS.Views.AboutPage"  Title="Explore">
  
    <StackLayout>
    
        <local:CustomMap x:Name="customMap" IsShowingUser="True"
                     MapType="Street" />
    

    </StackLayout>
</ContentPage>

下面是我的 Android 自定义渲染器

    using Android.Content;
using Android.Gms.Maps;
using Android.Gms.Maps.Model;
using Android.Widget;
using MAPS;
using MAPS.Droid;
using MAPS.Views;
using Newtonsoft.Json;
using Rg.Plugins.Popup;
using Rg.Plugins.Popup.Animations;
using Rg.Plugins.Popup.Contracts;
using Rg.Plugins.Popup.Enums;
using Rg.Plugins.Popup.Services;
using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Maps.Android;
using static MAPS.Droid.CustomMapRenderer;

[assembly: ExportRenderer(typeof(CustomMap),typeof(CustomMapRenderer))]

namespace MAPS.Droid
{

    public class CustomMapRenderer : Xamarin.Forms.Maps.Android.MapRenderer,GoogleMap.IInfoWindowAdapter
    {
        List<CustomPin> customPins;
        public string popInfo;
        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;
                Control.GetMapAsync(this);
            }
        }
        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();
            
       //     CustomPin p = new CustomPin();
            //foreach (var cp in customPins)
            //{
            //    if (cp.Position == pin.Position)
            //    {
            //        p = cp;
            //    }
            //}
            marker.SetPosition(new LatLng(pin.Position.Latitude,pin.Position.Longitude));
            marker.SetTitle(pin.Label);
         
            // marker.SetIcon(BitmapDescriptorFactory.FromFile(p.icon));
            if (pin.Address.Contains('*'))
            {
                marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.pin2));
            }
            else
            {
                marker.SetIcon(BitmapDescriptorFactory.Fromresource(Resource.Drawable.pin));
            }
            marker.Visible(true);
            var a = NativeMap.AddMarker(marker);
                 a.ShowInfoWindow();



            //  marker.SetSnippet(pin.Address.Replace("*"," "));
            return marker;
        }

        void OnInfoWindowClick(object sender,GoogleMap.InfoWindowClickEventArgs e)
        {

            getPlaceData(markerdata.markerData.title,markerdata.markerData.lat,markerdata.markerData.lng);
            showPopUp();


        }
    

        public Android.Views.View GetInfoContents(Marker marker)
        {


            return null;
        }
        public void  myMod(Marker marker)
        {

        }

        public Android.Views.View GetInfoWindow(Marker marker)
        {
            markerdata.markerData.title = marker.Title;

            markerdata.markerData.lat = marker.Position.Latitude.ToString("0.#####");
            markerdata.markerData.lng = marker.Position.Longitude.ToString("0.#####");
            // ds.Id = marker.Id;
        //    getPlaceData(marker.Title,marker.Position.Latitude.ToString("0.#####"),marker.Position.Longitude.ToString("0.#####"));
         //   showPopUp();
       








            return null;
        }

        public string Number;
     
        private async void showPopUp()
        {
          
            var Pr = new Views.PopUp();
            var scaleAnimation = new ScaleAnimation
            {
                PositionIn = MoveAnimationoptions.Right,PositionOut = MoveAnimationoptions.Left
            };

            Pr.Animation = scaleAnimation;

            await PopupNavigation.PushAsync(Pr);

        }
        CustomPin GetCustomPin(Marker annotation)
        {

            return null;
        }
        private void getPlaceData(String name,String Lat,String Lng)
        {
            var assembly = IntrospectionExtensions.GetTypeInfo(typeof(AboutPage)).Assembly;
            Stream stream = assembly.GetManifestResourceStream("MAPS.Places.json");
            string text = string.Empty;
            using (var reader = new StreamReader(stream))
            {
                text = reader.ReadToEnd();
            }
            var resultObject = JsonConvert.DeserializeObject<Places>(text);

            foreach (var place in resultObject.results)
            {
                if((name==place.id)&&(Lat ==place.geometry.location.lat.ToString("0.#####"))&&(Lng ==place.geometry.location.lng.ToString("0.#####")))
                {
                    getData.Instance.Id = place.id;
                    getData.Instance.lat = place.geometry.location.lat.ToString("0.#####");
                    getData.Instance.lng = place.geometry.location.lng.ToString("0.#####");
                    getData.Instance.marker2 = place.name;
                    getData.Instance.family = place.family;
                   getData.Instance.origin = place.Origin;
                    getData.Instance.date = place.Date;
                    getData.Instance.commonName = place.CommonName;
                //    getData.Instance.title = marker.Title;
             
                }

            }

        }
    }
      
}