Swift Image retrieving from Parse sdk

Question

I'm currently writing a social networking application in Swift. Inside my app I have feature that a user can send a message to the timeline with a image attached. I want to be able to retrieve the image and preview it using a UIImageView inside my timeline. I wrote the following function but I'm receiving a "unexpected found nil while unwrapping a Optional Value" error. I'm hoping somebody in the community can point out what I'm doing wrong.

func loadImages()
{
    var query = PFQuery(className: "imagesUploaded")
    query.orderByDescending("objectID")

    query.findObjectsInBackgroundWithBlock {
        (objects:[AnyObject]!,error:NSError!) -> Void in
        if error == nil {
            let imagesobjects = objects as [PFObject]

            for object : PFObject in objects as [PFObject] {
                let image = object["filename"] as PFFile

                image.getDataInBackgroundWithBlock {
                    (imageData:NSData!, error:NSError!) -> Void in
                    if error == nil {
                        let finalimage = UIImage(data: imageData)
                        self.timelineImages.append(finalimage!)
                        self.timelineimage.image = finalimage?
                    }
                }
            }
        }
    }
}

Answer 1

Given that the error is happening around these lines:

self.timelineImages.append(finalimage!)
self.timelineimage.image = finalimage?

I would suggest it is either finalimage , timelineImages or timelineimage .

For finalimage I would use if let :

if let finalimage = UIImage(data: imageData) {
    self.timelineImages.append(finalimage)
    self.timelineimage.image = finalimage
}

This safely runs the code only if finalimage got a value.

If one of the others is coming back as nil you can solve that with ? . thus your final code looks like this:

if let finalimage = UIImage(data: imageData) {
    self.timelineImages?.append(finalimage)
    self.timelineimage?.image = finalimage
}