swift - fatal error Firebase 快照

Question

每次我运行这个我都会得到这个错误: fatal error :

Unexpectedly found nil while unwrapping an Optional value 2017-09-15 06:30:04.650075+0200 RollerBank[845:211470] fatal error: unexpectedly found nil while unwrapping an Optional value.

我不知道我做错了什么。有人能帮助我吗？

func reload(){
            //get data
            Database.database().reference().child("Rollerbanken").observe(.value, with: { (snapshot) in



                for item in snapshot.children{

                    if let itemDict = snapshot.value as? NSDictionary {


                        let annotation = MKPointAnnotation()


                        annotation.title = itemDict["TypeControle"] as! String
                        let tijd = itemDict["Tijd"] as! String
                        annotation.subtitle = "Geplaatst om \(tijd)"


                        let getLatitude = itemDict["Latitude"] as! Double
                        let getLongitude = itemDict["Longitude"] as! Double

                        annotation.coordinate = CLLocationCoordinate2D(latitude: getLatitude, longitude: getLongitude)

                        self.map.addAnnotation(annotation)

                    }
                }
            })
        }

Answer 1

使用它来解析从 Firebase 收到的值。

if let value = snapshot.value as? Dictionary<String, Any> {

    for key in value.keys {
            if let itemDict = value[key] as? Dictionary<String, AnyObject> {

                let annotation = MKPointAnnotation()
                annotation.title = itemDict["TypeControle"] as! String
                let tijd = itemDict["Tijd"] as! String
                annotation.subtitle = "Geplaatst om \(tijd)"

                let getLatitude = itemDict["Latitude"] as? String
                let getLongitude = itemDict["Longitude"] as? String
                if let lat = getLatitude, let long = getLongitude {
                    annotation.coordinate = CLLocationCoordinate2D(latitude: Double(lat), longitude: Double(long))

                  self.map.addAnnotation(annotation) 
            }
       }
    }
 }