How do i change this code to query by creation date with swift from parse data?

Question

I have this code to retrieve images from parse data.

How do I query it by creation date? I tried using findObjectsInBackgroundWithBlock but it wont work with a PFFile. What do i do?

Also, as a side question, sometimes when i place the images in a UIImageView they are upside down or sideways. Why?

if let objects = objects as? [PFObject] {
                    for object in objects {

    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 you have a secure internet connection")        
         }                                        
       dispatch_async(dispatch_get_main_queue()) 
          {
            self.collectionView.reloadData()
            println("Finished Pictures")
          }
       })
     }    
}}

What do you mean query by creation date? If you parse a JSON you have an object with keys and values. — Aggressor, May 22 '15 at 21:33
You need to make a sort algorithm. http://stackoverflow.com/a/24130092/3324388 — Aggressor, May 22 '15 at 21:35
Thats not the answer. the answer has to do with something like adding a PFQuery to the code. But i don't know where to add it. — nachshon fertel, May 22 '15 at 21:36
It looks like you have an array of objects that refer to image files. Do you want to order those objects by creation? If so, then yes, you can apply sorts to the query that results in that array of objects. (Descending by creation date is the default). — danh, May 22 '15 at 22:08

score 0 · Answer 1 · answered May 23 '15 at 09:13

You have a set of objects which all reference an image file, but probably a set of other things too, and the image can likely be changed. So, the object creation date isn't the same as the image creation date and the image file doesn't know (or at least doesn't expose) it's creation date. You're also currently always adding the images to the start of the array so the position will be set by how big (and therefore how long it takes to download) each image is. Also, trying to download lots of images at the same time could just mean you get lots of timeouts.

So, really you should have a column on your object which holds the date at which the image was updated, and sort the objects by that date. As you download the images you place them into the image array in the same index as the owning object in its array (pad the array out with NSNull so you know what's going on).

How do i change this code to query by creation date with swift from parse data?

1 Answers1