ios - 从 '[PFObject]?' 向下转换到 '[PFObject]' 仅解开可选值

Question

我正在将解析查询保存到数组中，但在 if letobjects=objectsas? 上出现以下错误？ [PF对象]

并且出现以下错误:从“[PFObject]?”向下转型？到“[PFObject]”仅解包选项。

有人知道如何解决这个问题吗？

func getArray(funcstring: String){
        
        var userGeoPoint: PFGeoPoint
        PFGeoPoint.geoPointForCurrentLocationInBackground {
            (geoPoint: PFGeoPoint?, error: NSError?) -> Void in
            if error == nil {
        
            userGeoPoint = geoPoint!
            }
        }
        
        
        var searchQuery: [String] = [String]()
        
        var query = PFQuery(className:"User")
        query.whereKey("geoLocation", nearGeoPoint:userGeoPoint)
        query.limit = 100
        query.findObjectsInBackgroundWithBlock {
            (objects: [PFObject]?, error: NSError?) -> Void in
            if error == nil {
                if let objects = objects as? [PFObject] {
                    for object in objects {
                        self.searchQuery.append(object.objectForKey("objectId") as! String)
                        
                    }
                    
                }
            } else {
                print("\(error?.userInfo)")
            }
        }

        
        
        
        
                }

Answer 1

objects 声明为 [PFObject]?。

您要将对象向下转换为编译器已经知道的内容。

只需检查nil

if let unwrappedObjects = objects {
  for object in unwrappedObjects {
     self.searchQuery.append(object.objectForKey("objectId") as! String)    
  }
}

或者仍然“更快”

if let unwrappedObjects = objects {
   self.searchQuery = unwrappedObjects.map{ $0["objectId"] as! String }   
}