使用Swift从Parse加载图像

Question

I've written my code for retrieving images from my Parse data console so that they will appear in my Storyboard for my Swift app, but I'm not sure how to make an IBOutlet connect to the UIImageView I added to my Storyboard so that the image from Parse will actually appear in its place. Here's the code I have so far in my ViewController:

var imageResources : Array<UIImage> = []

override func viewDidLoad() {
    super.viewDidLoad()


func loadImages(){

    var query2 = PFQuery(className: "VoteCount")
    query.findObjectsInBackgroundWithBlock ({(objects:[AnyObject]!, error: NSError!) in
        if(error == nil){
            let imageObjects = objects as [PFObject]
            for object in objects {
                let thumbNail = voteCount1["image"] as PFFile
                thumbNail.getDataInBackgroundWithBlock({
                    (imageData: NSData!, error: NSError!) -> Void in
                    if (error == nil) {
                        let image = UIImage(data:imageData)
                        self.imageResources.append(image!)
                        println(image)
                    }
                })
            }
        }
        else{
            println("Error in retrieving \(error)")
        }
        })
    }

}

What kind of IBOutlet do I make that connects to the UIImageView I've added to my Main.storyboard? I'm just not sure what to name it that will call the image from Parse that I'm trying to retrieve.

Answer 1

control-drag from your UIImageView to your Swift file, outside the methods but inside the implementation. name it myImageView.

You can't call println on an image.

Then after the line if (error == nil) { try the following

if let image = UIImage(data:imageData) {
    dispatch_async(dispatch_get_main_queue()) {
         self.myImageView.image = image
    }
}

Or something to that effect. You need to be sure:

1. the image exists
2. you do anything with UI updates on the main thread (that's what dispatch_async(dispatch_get_main_queue()) {} accomplishes

Try it and let me know if that helps. I'm on the road right now but when I get a chance to sit I'll circle back and check this out.

One last trick: you can put a breakpoint on lines where you get an image. Then when the application pauses, you can hover over the word image in the line if let image = UIImage(data:imageData) { and click on the eye icon in the popup. You should then be able to view the image from Parse. If the image doesn't appear when you click the eye icon, you probably have additional debugging to do (does the image exist, is your logic up to that point correct, etc).