ios - 无法从 Parse 对象检索 createdAt 值

Question

我无法从每个对象的 Parse 中获取 createdAt 值。而且我不想在数据就在那里时将额外的时间戳保存为字符串。

这是我正在做的事情的 list 。我希望有人能提供帮助 ---------------------------------------------- ----------------------

 var followArray = [String]()
        var resultsNameArray = [String]()
        var resultsIcon = [PFFile]()
        var resultsImgArray = [PFFile?]()
        var resultsTimeTampArray = [NSDate?]()

    -------------------------------------------------------------------






     func refreshResult()
            {

            var followQuery = PFQuery(className: "Follow") 
   followQuery.whereKey("user", equalTo: PFUser.currentUser()!.username!) 
 followQuery.findObjectsInBackgroundWithBlock { (objects: [AnyObject]?, error: NSError?) -> Void in
                    if error == nil
                    {
                        for object in objects!
                        {                      self.followArray.append(object.objectForKey("Following") as! String)                    
                        }

                        var query = PFQuery(className: "Moments")
                        query.whereKey("userName", containedIn: self.followArray)

                        query.addDescendingOrder("createdAt")
                        query.findObjectsInBackgroundWithBlock { (objects: [AnyObject]?, error: NSError?) -> Void in

                            if error == nil
                            {
                                for object in objects!
                                { 
                               self.resultsNameArray.append(object.objectForKey("profileName") as! String)
                                self.resultsIcon.append(object.objectForKey("icon") as! PFFile) 
                          self.resultsImgArray.append(object.objectForKey("image") as? PFFile) 

        //tried to use  "createdAt" property  but it i still getting nil value from Parse  
                       self.resultsTimeTampArray.append(object.objectForKey("createdAt") as! NSDate)
                                }
        //reload table
         self.resultsTable.reloadData()
                            }
                        }
                    }
                }

        -----------------------------------------------------------------------
            func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
            {        
                var cell:TimelineCell = tableView.dequeueReusableCellWithIdentifier("Cell") as! TimelineCell

               enter code here //I'v got an error here!
                //fatal error: unexpectedly found nil while unwrapping an Optional value
    // dataFormatter
                var dateFormatter:NSDateFormatter = NSDateFormatter()
                dateFormatter.dateFormat = "yyyy-MM-dd"
                var strDate = dateFormatter.stringFromDate(self.resultsTimeTampArray[indexPath.row]!)       
                return cell
            }

Answer 1

不要使用 objectForKey 访问它，只需通过 createdAt 属性直接访问它。

正如文档中明确指出的那样，键:

This does not include createdAt, updatedAt, authData, or objectId. It does include things like username and ACL.