Parse.com PFQuery按时间顺序排列

Question

在我的parse.com“帖子”中，它看起来像这样：

我的查询看起来像这样：

IPublishBus

NSDate扩展：

func QueryImagesFromParse(){
        var query = PFQuery(className: "Posts")
        query.orderByDescending("createdAt")
        query.findObjectsInBackgroundWithBlock { (objects:[AnyObject]?, error:NSError?) -> Void in
            if error == nil
            {
                if let newObjects = objects as? [PFObject] {

                    for oneobject in newObjects {
                        var text = oneobject["imageText"] as! String
                        var username = oneobject["username"] as! String
                        var time = oneobject.createdAt
                        var userImageFile = oneobject["imageFile"] as! PFFile
                        userImageFile.getDataInBackgroundWithBlock({ (imageData:NSData?, error:NSError?) -> Void in
                            if error == nil {
                                let newImage = UIImage(data: imageData!)

                                var OneBigObject = Details(username: username, text: text, CreatedAt: time!, image: newImage!)
                                self.arrayOfDetails.append(OneBigObject)

                                self.collectionView.reloadData()
                            }
                        })
                    }
                }
            }
        }
    }

我已尝试使用extension NSDate { var timeAgo: String { let minute = 60 let hour = 60 * minute let day = 24 * hour let secondsAgo = Int(NSDate().timeIntervalSinceDate(self)) if secondsAgo < 0 { return "later" } if secondsAgo == 0 { return "now" } if secondsAgo == 1 { return "1 second ago" } if secondsAgo < minute { return "\(secondsAgo) seconds ago" } if secondsAgo < (2 * minute) { return "1 minute ago" } if secondsAgo < hour { return "\(secondsAgo/minute) minutes ago" } if secondsAgo < 2 * hour { return "1 hour ago" } if secondsAgo < day { return "\(secondsAgo / hour) hours ago" } let formatter = NSDateFormatter() formatter.dateFormat = "M/d/yy" return formatter.stringFromDate(self) } } 对最新上传的内容进行排序，但它不起作用。上传按随机顺序排列，而不是最新的。我究竟做错了什么？我在viewDidLoad中运行query.orderByDescending。