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我正在尝试从 Parse 后端创建注释，但出现错误 '[PFObject]?' is not convertible to '[PFObject]'

我的代码基于我在这里找到的一个问题Query a GeoPoint from Parse and add it to MapKit as MKAnnotation?

这是我的代码和错误的图片。代码照片

{

mapView.showsUserLocation = true
mapView.delegate = self
mapView.setUserTrackingMode(MKUserTrackingMode.Follow, animated: true)
MapViewLocationManager.delegate = self
MapViewLocationManager.startUpdatingLocation()


    var annotationQuery = PFQuery(className: "Movers")
     currentLoc = PFGeoPoint(location: MapViewLocationManager.location)
    annotationQuery.whereKey("ubicacion", nearGeoPoint: currentLoc, withinKilometers: 10)
    annotationQuery.findObjectsInBackgroundWithBlock {
        (movers, error) -> Void in
        if error == nil {
            // The find succeeded.
            print("Successful query for annotations")

            let myMovers = movers as [PFObject]

                for mover in myMovers {
                let point = movers["ubicacion"] as PFGeoPoint
                let annotation = MKPointAnnotation()
                annotation.coordinate = CLLocationCoordinate2DMake(point.latitude, point.longitude)
                self.mapView.addAnnotation(annotation)

        }

        }else {
            // Log details of the failure
            print("Error: \(error)")
        }
    }

}

提前致谢

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1 回答 1

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myMovers是 a [PFObject]?，一个可选的PFObjects 数组（可能是一个PFObjects 或 s的数组nil）。因为它是可选的，所以它不能直接转换为非可选，因为您不能转换nil为[PFObject]. 所以你真正想要的是在这里做一个条件转换，as?并把它放在一个if let语句中。像这样

if let myMovers = movers as? [PFObject] {
    // Use myMovers to do what you want 
}

只有当moversis a[PFObject]和 not时，才会执行大括号中的内容nil。

于 2015-10-06T23:29:47.553 回答