如何在单击 xamarin.forms.maps iOS c# 时更改 pin 图标

Posted 2023-04-13

【中文标题】如何在单击 xamarin.forms.maps iOS c# 时更改 pin 图标

【英文标题】：How to change pin icon on click in xamarin.forms.maps iOS c#

【发布时间】：2021-12-04 12:08:00

【问题描述】：

我想在点击图钉时更改图钉图标。

我从OnDidSelectAnnotationView 中的GetViewForAnnotation 方法中复制了这段代码，但我不知道如何返回 annotationView。

我不确定这是否是正确的方法，但我能否获得一个示例，说明如何在单击标记时更改图标？

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

        if (customView.Name.Equals("Xamarin"))
        
            customPinView.Frame = new CGRect(0, 0, 200, 84);

            customPinView.Center = new CGPoint(0, -(e.View.Frame.Height + 75));

            e.View.AddSubview(customPinView);
        

        var pin = GetCustomPin(c_annotation as MKPointAnnotation);
        int mapCode = customView.MapCode;
        var result = GetDataFromAPI(mapCode);
        var result2 = GetInfoFromStation(mapCode);

        MessagingCenter.Send<object, IEnumerable<AlertLevel>>(this, "PinSelected", result);
        MessagingCenter.Send<object, IEnumerable<StationInfoOnClick>>(this, "StationInfo", result2);


        MKAnnotationView annotationView = null;

        if (annotationView == null)
        
            annotationView = new CustomMKAnnotationView(c_annotation, pin.Name);
            annotationView.CalloutOffset = new CGPoint(0, 0);
            ((CustomMKAnnotationView)annotationView).Name = pin.Name;
            ((CustomMKAnnotationView)annotationView).Url = pin.Url;
            ((CustomMKAnnotationView)annotationView).Address = pin.Address;
            //Add First Line
            ((CustomMKAnnotationView)annotationView).AlertLevel = pin.AlertLevel;

            if (pin.AlertLevel == 1)
            
                annotationView.Image = UIImage.FromFile("red.png");
            
            else if (pin.AlertLevel == 2)
            
                annotationView.Image = UIImage.FromFile("yellow.png");
            
            else if (pin.AlertLevel == 3)
            
                annotationView.Image = UIImage.FromFile("orange.png");
            
            else if (pin.AlertLevel == 4)
            
                annotationView.Image = UIImage.FromFile("red.png");
            

            //Add Second Line
            ((CustomMKAnnotationView)annotationView).CodeNum = pin.CodeNum;

            ((CustomMKAnnotationView)annotationView).MapCode = pin.MapCode;
        

        annotationView.CanShowCallout = true;

        configureDetailView(annotationView);

        return annotationView;
    

我尝试将void OnDidSelectAnnotationView 更改为MKAnnotationView OnDidSelectAnnotationView 我收到此方法的错误：

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

        if (e.OldElement != null)
        
            var nativeMap = Control as MKMapView;
            nativeMap.GetViewForAnnotation = null;
            nativeMap.CalloutAccessoryControlTapped -= OnCalloutAccessoryControlTapped;
            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.CalloutAccessoryControlTapped += OnCalloutAccessoryControlTapped;
            nativeMap.DidSelectAnnotationView += OnDidSelectAnnotationView;
            nativeMap.DidDeselectAnnotationView += OnDidDeselectAnnotationView;
        
    

错误是：Error CS0407: 'MKAnnotationView CustomMapRenderer.OnDidSelectAnnotationView(object, MKAnnotationViewEventArgs)' has the wrong return type (CS0407) (MaritsaTundzhaForecast.ios)

是否有其他方法可以在点击时更改地图标记图标？

这是我的GetViewForAnnotation 方法：

protected override MKAnnotationView GetViewForAnnotation(MKMapView mapView, IMKAnnotation annotation)
    

        //от mainpage извикваш метода

        MKAnnotationView annotationView = null;

        if (annotation is MKUserLocation)
            return null;

        var customPin = GetCustomPin(annotation as MKPointAnnotation);

        //Get Value
        c_annotation = annotation;

        if (customPin == null)
        
            throw new Exception("Custom pin not found");
        

        annotationView = mapView.DequeueReusableAnnotation(customPin.Name);
        if (annotationView == null)
        
            annotationView = new CustomMKAnnotationView(annotation, customPin.Name);
            annotationView.CalloutOffset = new CGPoint(0, 0);
            ((CustomMKAnnotationView)annotationView).Name = customPin.Name;
            ((CustomMKAnnotationView)annotationView).Url = customPin.Url;
            ((CustomMKAnnotationView)annotationView).Address = customPin.Address;
            //Add First Line
            ((CustomMKAnnotationView)annotationView).AlertLevel = customPin.AlertLevel;

            if (customPin.AlertLevel == 1)
            
                annotationView.Image = UIImage.FromFile("green.png");
            
            else if (customPin.AlertLevel == 2)
            
                annotationView.Image = UIImage.FromFile("yellow.png");
            
            else if (customPin.AlertLevel == 3)
            
                annotationView.Image = UIImage.FromFile("orange.png");
            
            else if (customPin.AlertLevel == 4)
            
                annotationView.Image = UIImage.FromFile("red.png");
            

            //Add Second Line
            ((CustomMKAnnotationView)annotationView).CodeNum = customPin.CodeNum;

            ((CustomMKAnnotationView)annotationView).MapCode = customPin.MapCode;
        


        annotationView.CanShowCallout = true;

        configureDetailView(annotationView);

        return annotationView;
    

我想点击放置不同大小的相同图标。

我用这个example

【问题讨论】：

您不能只更改被覆盖方法的返回类型。您尝试做的可能需要比标准地图控件更可定制的东西

当我点击不同大小的标记时，我想更改标记上的图标..

【参考方案1】：

在 DidSelectAnnotationView 中设置 pin 图像，如：

nativeMap.DidSelectAnnotationView += OnDidSelect;

 private void OnDidSelect(object sender, MKAnnotationViewEventArgs e)
        
            e.View.Image = UIImage.FromFile("monkey.png");
        

【讨论】：

谢谢！你能在这里检查我关于更换引脚的问题吗..我有一个小问题..***.com/questions/69620109/…