simple image data passing from collection view to view controller fail

Question

This is seriously starting to drive me crazy, since it s really simple. I have a collectionviewcell that gets images from phone library

When i tap a cell, i get the index of the fetched collection (i m using Photo Framework), then send the selected image (through PHImageManage's imageFromAsset) to a new view controller, assign this image to a new UIimage property and then try to display it on my UIimageView outlet FAIL ! In the debug Window, I can see that the image is passing from the collectionviewcontroller to my FullImageViewController, and I dont understand why I get an error on my outlet (returns NIL for ever)

here s a bit of code, and a bug capture -- The collectioncontroller first

 func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell: PhotoCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(identifier, forIndexPath: indexPath) as! PhotoCollectionViewCell

 //   cell.contentView.backgroundColor = UIColor.redColor()
    let asset: PHAsset = photosAsset[indexPath.item] as! PHAsset

    PHImageManager.defaultManager().requestImageForAsset(asset, targetSize: cellSize, contentMode: .AspectFit, options: nil) { (reuslt:UIImage?, info:[NSObject : AnyObject]?) -> Void in
        if let image = reuslt {
            cell.displaythunmb(image)
        }
    }

    return cell

}

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {

    let asset=photosAsset[indexPath.item] as! PHAsset
    let size:CGSize = CGSizeMake(200, 200)

    PHImageManager.defaultManager().requestImageForAsset(asset, targetSize: size, contentMode: .AspectFit, options: nil) { (result:UIImage?, info:[NSObject : AnyObject]?) -> Void in
        let controller:FullImageViewController = FullImageViewController()
        if let image = result {
        controller.dislpayFullImage(image)
    }
    }

    performSegueWithIdentifier("gofull", sender: self)

}

and here's the fullImageViewController

class FullImageViewController: UIViewController {
var image:UIImage = UIImage()

@IBOutlet weak var fullimage: UIImageView!


override func viewDidLoad() {
    super.viewDidLoad()
    navigationController?.hidesBarsOnTap = true

}
override func viewWillAppear(animated: Bool) {
    //dislpayFullImage()

}

func dislpayFullImage(fullimg:UIImage){

    if let monimage:UIImage? = fullimg {
        image=monimage!
         fullimage.image = image
    }

}

}

this gives me "fatal error: unexpectedly found nil while unwrapping an Optional value" on the "fullimage.image = image" line

I've tried to unwrap, force unwrap and so on, nothing seems to work

In the debt window, when I follow the properties I have to following :

fullimg UIImage 0x00007ff3fb6506f0 0x00007ff3fb6506f0 self test.FullImageViewController 0x00007ff3fb6526e0 0x00007ff3fb6526e0 UIKit.UIViewController UIViewController
image UIImage 0x00007ff3fb6506f0 0x00007ff3fb6506f0

fullimage UIImageView! nil None

monimage UIImage? 0x00007ff3fb6506f0 0x00007ff3fb6506f0

Any idea where I m messing up >

Answer 1

You are creating an instance of FullImageViewController programmatically but you are using an IBOutlet in this view controller.

You probably want to instantiate it using storyboard, so you'll have to do something like this:

let storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
let destination = storyboard.instantiateViewControllerWithIdentifier("yourIdentifier") as! FullImageViewController

Don't forget to set the identifier for your FullImageViewController though.

EDIT: Since you're using a segue, you should handle passing the data in prepareForSegue(_:):

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "gofull" {
        let destination = segue.destinationViewController as! FullImageViewController
        destination.someImage = result
    }
}

But accessing fullimage before the view is loaded will still cause a crash, so you should try passing the value to fullimage in viewWillAppear or viewDidLoad.

In your FullImageViewController:

var someImage: UIImage?

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    if let image = someImage { fullimage.image = image }
}