Xamarin.forms xamarin forms maps中的长攻丝和插针

我使用了Xamarin.Forms.Maps nuget包并在设备上显示了地图。我能够在下面代码的帮助下在外部按钮点击上显示pin，但无法在地图点击上在特定位置放置pin

public void addPin(double latitude, double longitude, string labelName)
{
     Position position = new Position(latitude, longitude);
    _assignedPin = new Pin
    {
        Type = PinType.Place,
        Position = position,
        Label = labelName,
        Address = "custom detail info"
    };
    map.Pins.Add(_assignedPin);
}

---

我随后在map上获得lat long，但map不会在map上显示pin。

我们需要使用xamarin.forms.maps将渲染器本身中的代码添加到drop pin中

在Android:Renderer类中：

private void googleMap_MapClick(object sender, GoogleMap.MapClickEventArgs e)
{
    Map.Pins.Add(new Pin
    {
        Label = "Pin from tap",
        Position = new Position(e.Point.Latitude, e.Point.Longitude))
    }
}

[assembly: ExportRenderer(typeof(ExtMap), typeof(ExtMapRenderer))]
namespace Xamarin.iOS.CustomRenderers
{
    /// <summary>
    /// Renderer for the xamarin ios map control
    /// </summary>
    public class ExtMapRenderer : MapRenderer
    {
        private readonly UITapGestureRecognizer _tapRecogniser;

        public ExtMapRenderer()
        {
            _tapRecogniser = new UITapGestureRecognizer(OnTap)
            {
                NumberOfTapsRequired = 1,
                NumberOfTouchesRequired = 1
            };
        }

        protected override IMKAnnotation CreateAnnotation(Pin pin)
        {
            return base.CreateAnnotation(pin);
        }



        class BasicMapAnnotation : MKAnnotation
        {
            CLLocationCoordinate2D coord;
            string title, subtitle;

            public override CLLocationCoordinate2D Coordinate { get { return coord; } }
            public override void SetCoordinate(CLLocationCoordinate2D value)
            {
                coord = value;
            }
            public override string Title { get { return title; } }
            public override string Subtitle { get { return subtitle; } }
            public BasicMapAnnotation(CLLocationCoordinate2D coordinate, string title, string subtitle)
            {
                this.coord = coordinate;
                this.title = title;
                this.subtitle = subtitle;
            }
        }



        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);
        }

        private async void OnTap(UITapGestureRecognizer recognizer)
        {
            var cgPoint = recognizer.LocationInView(Control);
            var nativeMap = Control as MKMapView;

            var location = ((MKMapView)Control).ConvertPoint(cgPoint, Control);

            ((ExtMap)Element).OnTap(new Position(location.Latitude, location.Longitude));

            try
            {
                var lat = location.Latitude;
                var lon = location.Longitude;

                var placemarks = await Geocoding.GetPlacemarksAsync(lat, lon);

                var placemark = placemarks?.FirstOrDefault();
                if (placemark != null)
                {
                    var geocodeAddress =
                        $"AdminArea:       {placemark.AdminArea}\n" +
                        $"CountryCode:     {placemark.CountryCode}\n" +
                        $"CountryName:     {placemark.CountryName}\n" +
                        $"FeatureName:     {placemark.FeatureName}\n" +
                        $"Locality:        {placemark.Locality}\n" +
                        $"PostalCode:      {placemark.PostalCode}\n" +
                        $"SubAdminArea:    {placemark.SubAdminArea}\n" +
                        $"SubLocality:     {placemark.SubLocality}\n" +
                        $"SubThoroughfare: {placemark.SubThoroughfare}\n" +
                        $"Thoroughfare:    {placemark.Thoroughfare}\n";

                    Console.WriteLine(geocodeAddress);
                    var annotation = new BasicMapAnnotation(new CLLocationCoordinate2D(lat, lon), placemark.Thoroughfare, placemark.SubThoroughfare);
                    nativeMap.AddAnnotation(annotation);
                }
            }
            catch (FeatureNotSupportedException fnsEx)
            {
                // Feature not supported on device
                Console.WriteLine(fnsEx);
            }
            catch (Exception ex)
            {
                // Handle exception that may have occurred in geocoding
                Console.WriteLine(ex);
            }




        }

        protected override void OnElementChanged(ElementChangedEventArgs<View> e)
        {
            if (Control != null)
                Control.RemoveGestureRecognizer(_tapRecogniser);

            base.OnElementChanged(e);

            if (Control != null)
                Control.AddGestureRecognizer(_tapRecogniser);
        }
    }
}

在iOS渲染器类中：

private void googleMap_MapClick(object sender, GoogleMap.MapClickEventArgs e)
{
    Map.Pins.Add(new Pin
    {
        Label = "Pin from tap",
        Position = new Position(e.Point.Latitude, e.Point.Longitude))
    }
}

[assembly: ExportRenderer(typeof(ExtMap), typeof(ExtMapRenderer))]
namespace Xamarin.iOS.CustomRenderers
{
    /// <summary>
    /// Renderer for the xamarin ios map control
    /// </summary>
    public class ExtMapRenderer : MapRenderer
    {
        private readonly UITapGestureRecognizer _tapRecogniser;

        public ExtMapRenderer()
        {
            _tapRecogniser = new UITapGestureRecognizer(OnTap)
            {
                NumberOfTapsRequired = 1,
                NumberOfTouchesRequired = 1
            };
        }

        protected override IMKAnnotation CreateAnnotation(Pin pin)
        {
            return base.CreateAnnotation(pin);
        }



        class BasicMapAnnotation : MKAnnotation
        {
            CLLocationCoordinate2D coord;
            string title, subtitle;

            public override CLLocationCoordinate2D Coordinate { get { return coord; } }
            public override void SetCoordinate(CLLocationCoordinate2D value)
            {
                coord = value;
            }
            public override string Title { get { return title; } }
            public override string Subtitle { get { return subtitle; } }
            public BasicMapAnnotation(CLLocationCoordinate2D coordinate, string title, string subtitle)
            {
                this.coord = coordinate;
                this.title = title;
                this.subtitle = subtitle;
            }
        }



        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);
        }

        private async void OnTap(UITapGestureRecognizer recognizer)
        {
            var cgPoint = recognizer.LocationInView(Control);
            var nativeMap = Control as MKMapView;

            var location = ((MKMapView)Control).ConvertPoint(cgPoint, Control);

            ((ExtMap)Element).OnTap(new Position(location.Latitude, location.Longitude));

            try
            {
                var lat = location.Latitude;
                var lon = location.Longitude;

                var placemarks = await Geocoding.GetPlacemarksAsync(lat, lon);

                var placemark = placemarks?.FirstOrDefault();
                if (placemark != null)
                {
                    var geocodeAddress =
                        $"AdminArea:       {placemark.AdminArea}\n" +
                        $"CountryCode:     {placemark.CountryCode}\n" +
                        $"CountryName:     {placemark.CountryName}\n" +
                        $"FeatureName:     {placemark.FeatureName}\n" +
                        $"Locality:        {placemark.Locality}\n" +
                        $"PostalCode:      {placemark.PostalCode}\n" +
                        $"SubAdminArea:    {placemark.SubAdminArea}\n" +
                        $"SubLocality:     {placemark.SubLocality}\n" +
                        $"SubThoroughfare: {placemark.SubThoroughfare}\n" +
                        $"Thoroughfare:    {placemark.Thoroughfare}\n";

                    Console.WriteLine(geocodeAddress);
                    var annotation = new BasicMapAnnotation(new CLLocationCoordinate2D(lat, lon), placemark.Thoroughfare, placemark.SubThoroughfare);
                    nativeMap.AddAnnotation(annotation);
                }
            }
            catch (FeatureNotSupportedException fnsEx)
            {
                // Feature not supported on device
                Console.WriteLine(fnsEx);
            }
            catch (Exception ex)
            {
                // Handle exception that may have occurred in geocoding
                Console.WriteLine(ex);
            }




        }

        protected override void OnElementChanged(ElementChangedEventArgs<View> e)
        {
            if (Control != null)
                Control.RemoveGestureRecognizer(_tapRecogniser);

            base.OnElementChanged(e);

            if (Control != null)
                Control.AddGestureRecognizer(_tapRecogniser);
        }
    }
}

[程序集：ExportRenderer（typeof（ExtMap），typeof（extmaprederer））]
命名空间Xamarin.iOS.CustomRenders
{
/// 
///xamarin ios映射控件的渲染器
/// 
公共类ExtMapRenderer:MapRenderer
{
专用只读UITapGestureRecognizer\u TapRecognizer；
公共ExtMapRenderer（）
{
_TapRecognizer=新的UITapGestureRecognizer（OnTap）
{
NumberOfTapsRequired=1，
NumberOfTouchesRequired=1
};
}
受保护的覆盖IMKAnnotation CreateAnnotation（Pin）
{
返回base.CreateAnnotation（pin）；
}
类BasicManotation:MKAnnotation
{
CLLocationCoordinate2D coord；
字符串标题、副标题；
公共重写CLLocationCoordinate2D坐标{get{return coord；}}
公共覆盖无效SetCoordinate（CLLocationCoordinate2D值）
{
坐标=价值；
}
公共重写字符串标题{get{return Title；}}
公共重写字符串字幕{get{return Subtitle；}}
公共基本符号（CLLocationCoordinate2D坐标、字符串标题、字符串副标题）
{
this.coord=坐标；
this.title=标题；
this.subtitle=副标题；
}
}
受保护的覆盖无效OnElementPropertyChanged（对象发送方，PropertyChangedEventArgs e）
{
base.OnElementPropertyChanged（发送方，e）；
}
专用异步void OnTap（UITapGestureRecognitor识别器）
{
var cgPoint=识别器。位置视图（控制）；
var nativeMap=作为MKMapView的控件；
变量位置=（（MKMapView）控件）.ConvertPoint（cgPoint，控件）；
（（ExtMap）元素）.OnTap（新位置（location.Latitude，location.Longitude））；
尝试
{
var lat=位置、纬度；
var lon=位置。经度；
var placemarks=await Geocoding.GetPlacemarksAsync（lat，lon）；
var placemark=placemarks？.FirstOrDefault（）；
if（placemark！=null）
{
地理编码地址=
$“AdminArea:{placemark.AdminArea}\n”+
$“CountryCode:{placemark.CountryCode}\n”+
$“CountryName:{placemark.CountryName}\n”+
$“FeatureName:{placemark.FeatureName}\n”+
$“位置：{placemark.Locality}\n”+
$“PostalCode:{placemark.PostalCode}\n”+
$“SubAdminArea:{placemark.SubAdminArea}\n”+
$“子局部性：{placemark.SubLocality}\n”+
$“次通道：{placemark.subthoroughe}\n”+
$“通道：{placemark.thoroughure}\n”；
控制台写入线（地理编码地址）；
var注释=新的BasicPannotation（新的CLLocationCoordinate2D（纬度、经度）、placemark.大道、placemark.亚大道）；
nativeMap.AddAnnotation（注释）；
}
}
捕获（功能不支持异常fnsEx）
{
//设备上不支持此功能
控制台写入线（fnsEx）；
}
捕获（例外情况除外）
{
//处理地理编码中可能发生的异常
控制台写入线（ex）；
}
}
受保护的覆盖无效OnElementChanged（ElementChangedEventArgs e）
{
if（控件！=null）
Control.RemoveGestureRecognizer（_-TapRecognizer）；
基础。一个要素发生变化（e）；
if（控件！=null）
Control.AddGestureRecognizer（_-TapRecognizer）；
}
}
}

Hi，这个博客是基于自定义渲染器来显示地图的。你在安卓或IOS中测试它的设备。我从安卓开始。我用Android解决了这个问题。需要在iOS中测试并确认。之后我会发布我自己的答案。太好了！更新答案并记住标记后。^^