Images duplicating when adding to Array - ios

Question

I am using DKImagePickerController to select multiple images, displaying them on my VC and them when I press a button they upload to Parse.
I load 7 images, but only the ones visible on the screen (Which is 4, as I am using a collectionView with a horizontal scroll) upload at the begining then if I scroll across to the end and upload again It uploads all 7 images. And if I scroll back and then forwards again the images seem to add up 7 at a time, so if I scrolled 4 times back and forth I would end up uploading 28 images when I only selected 7!!
I'm guessing it something to do with the way I add the images I have selected to the image Array which I am doing in the cellForItemAtIndexPath.
Here is my code below, if anyone has incounted this before or knows the issue you help is very much appreciated!
#IBOutlet weak var previewOrShareButton: UIBarButtonItem!
#IBOutlet weak var collectionView: UICollectionView!
#IBOutlet weak var cancelButton: UIBarButtonItem!
var assets: [DKAsset]?
var images = [UIImage]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func selectImage(sender: AnyObject) {
let pickerController = DKImagePickerController()
pickerController.didSelectAssets = { (assets: [DKAsset]) in
print("didSelectAssets")
self.assets = assets
self.collectionView.reloadData()
}
pickerController.defaultSelectedAssets = self.assets
pickerController.maxSelectableCount = 7
pickerController.allowMultipleTypes = false
self.presentViewController(pickerController, animated: true) {}
}
#IBAction func postButton(sender: AnyObject) {
let post = PFObject(className: "Post")
post["username"] = PFUser.currentUser()!.username
for i in self.images.indices {
let imageData = self.images[i].lowestQualityJPEGNSData
let imageFile = PFFile(name: "image.JPEG", data: imageData)
post["imageArray\(i)"] = imageFile
}
post.saveInBackgroundWithBlock ({(success:Bool, error:NSError?) -> Void in
if error == nil {
}})
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
return self.assets?.count ?? 0
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! BlogCollectionViewCell
let asset = self.assets![indexPath.row]
asset.fetchOriginalImageWithCompleteBlock { (image, info) -> Void in
cell.image.image = image
self.images.append(image!)
}
print(images)
return cell
}

Answer 1

Anything in your cellForRow will run every time a cell is scrolled to so it's fetching too many images. Ideally add the following to your viewDidLoad unless you need to the user to download the images then add this to a button:
for object in assets {
object.fetchOriginalImageWithCompleteBlock { (image, info) -> Void in
self.images.append(image!)
pickerController.reloadData()
}
}
That will load all of the images into the array and then you can populate your cells with the images:
cell.image = images[indexPath.row]

Answer 2

Yes you are doing it in wrong way, as you are fetching the images in cellForItemAtIndexPath and then adding the images in array in the same method. So when you scroll your UICollectionView then images will fetched and added to the array as cellForItemAtIndexPath will called when you scroll or reload your UICollectionView.
I will make some changes in your code, hope it will help you.
#IBAction func selectImage(sender: AnyObject) {
let pickerController = DKImagePickerController()
pickerController.didSelectAssets = { (assets: [DKAsset]) in
print("didSelectAssets")
assets.fetchOriginalImageWithCompleteBlock { (image, info) -> Void in
self.images.append(image!)
self.collectionView.reloadData()
}
}
pickerController.defaultSelectedAssets = self.assets
pickerController.maxSelectableCount = 7
pickerController.allowMultipleTypes = false
self.presentViewController(pickerController, animated: true) {}
}
and then cellForItemAtIndexPath will be
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! BlogCollectionViewCell
let asset = self.assets![indexPath.row]
cell.image.image = image
return cell
}