Question

我想在地图上使用两个不同的引脚，这是我的代码：

    func mapView (_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView?
{

    //avoid for user location
    if (annotation is MKUserLocation) {
        return nil
    }

    let reuseId = "annId"
    var anView = mapView.dequeueReusableAnnotationView(withIdentifier: reuseId)

    if anView == nil {

        if(annotation.subtitle! == "Offline"){

            anView = MKAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
            anView!.image = UIImage(named:"offIceCream.pdf")!
            anView!.canShowCallout = true

        }

        if(annotation.subtitle! == "Online"){

            anView = MKAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
            anView!.image = UIImage(named:"onIceCream.pdf")!
            anView!.canShowCallout = true
        }

    } else {

        anView!.annotation = annotation
    }

    return anView
}

问题在于它没有根据注释的字幕设置正确的图标。出于某种原因，有时它可以正常工作，有时它的工作方式相反（在离线注释上设置在线图标，反之亦然）。知道为什么会这样吗？。

提前致谢！

Answer 1

因为您忘记更新已经排队的注释视图的.image：

if anView == nil {
  ...
}
else {
  anView!.annotation = annotation

  if (annotation.subtitle! == "Offline") {
    anView!.image = UIImage(named:"offIceCream.pdf")!
  }
  else if (annotation.subtitle! == "Online") {
    anView!.image = UIImage(named:"onIceCream.pdf")!
  }
}

编写整个逻辑的更清晰的方法是：

func mapView (_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView?
{
  if (annotation is MKUserLocation) {
    return nil
  }
  var anView = mapView.dequeueReusableAnnotationView(withIdentifier: "annId")

  if anView == nil {
     anView = MKAnnotationView(annotation: annotation, reuseIdentifier: "annId")
  } 
  else {
    anView?.annotation = annotation
  }

  anView?.canShowCallout = true

  if (annotation.subtitle! == "Offline") {
    anView?.image = UIImage(named: "offIceCream.pdf")
  }
  else if (annotation.subtitle! == "Online") {
    anView?.image = UIImage(named: "onIceCream.pdf")
  }
  return anView
}

如何在地图上添加2个不同的引脚？ - 斯威夫特

1 个答案: