ios - How to query an PFFile By Creation Date -

i using code retrieve images parse data...

if let userpicture = object.valueforkey("image") as? pffile {       userpicture.getdatainbackgroundwithblock({ (imagedata: nsdata?, error: nserror?) -> void in            if (error == nil) {                 let image = uiimage(data:imagedata!)                 self.imagearray.insert(image!, atindex: 0)            }            else {                 self.alert("error: \(error!) \(error!.userinfo!)", message: "make sure have secure internet connection")            }            dispatch_async(dispatch_get_main_queue()) {                 println("finished pictures")            }       })  } 

and using code retrieve string parse:

 var stuffarray = [string]()   var query = pfquery(classname:"classname")  query.findobjectsinbackgroundwithblock {             (objects: [anyobject]?, error: nserror?) -> void in        if error == nil {            // find succeeded.            println("successfully retrieved \(objects!.count) scores.")            // found objects            if let objects = objects as? [pfobject] {                 object in objects {                      stuffarray.append(object.valueforkey("column")! as! string)                 }            } else {                 // log details of failure                 println("error: \(error!) \(error!.userinfo!)")            }             dispatch_async(dispatch_get_main_queue()) {                 self.alert("\(stuffarray)", message: "")            }       }  }      

i know how query second example adding following code:

query.orderbyascending("createdat") 

my question is, how query first example(image) same way did in second example? tried using following code, error:

userpicture.orderbyascending("createdat") 

i tried using following code, text being returned correctly, images still returned in random order...

var query = pfquery(classname:"featured") query.orderbydescending("createdat") query.findobjectsinbackgroundwithblock {     (objects: [anyobject]?, error: nserror?) -> void in      if error == nil {         // find succeeded.         println("successfully retrieved \(objects!.count) items.")         // found objects         if let objects = objects as? [pfobject] {             object in objects {                  self.namearray.insert(object.valueforkey("text")! as! string, atindex: 0)                 self.itemnamearray.insert(object.valueforkey("itemname")! as! string, atindex: 0)                   let userimagefile = object["image"] as! pffile                 userimagefile.getdatainbackgroundwithblock {                     (imagedata: nsdata?, error: nserror?) -> void in                     if error == nil {                         if let imagedata = imagedata {                             let image = uiimage(data:imagedata)                              self.imagearray.insert(image!, atindex: 0)                         }                     }                        dispatch_async(dispatch_get_main_queue()) {                          self.loading.hidden = true                          self.collectionview.reloaddata()                      }                  }                 }           }     } else {         // log details of failure         println("error: \(error!) \(error!.userinfo!)")      }          } 

in response to, "i changed 'append', , arrays images still in random order. 2 other string items work perfectly. why images. please give answer in swift.":

the reason why images still in random order because downloading asynchronously server. pffile getdatainbackgroundwithblock runs in background , smaller files may complete faster larger files may have started earlier.

you should not downloading images until ready display them in uicollectionview or uitableview. when render cell, call pffile getdatainbackgroundwithblock , then.