Collection View displays duplicates on refresh and then deletes them - ios

Question

I'm working with a collectionView right now and when I activate the refresh control, it adds a duplicate picture to the data source set for every picture in the set, and then makes it disappear and things go back to normal by the time the refresh control is done. Here's a YouTube video I uploaded to clearly show you what is going on.
https://youtu.be/Q9ZFd-7tSRw
It would seem logical that the data source set would be getting the same data from the API I am using, then displaying it, the duplicate data then getting deleting from the array, and then the collection view being reloaded once more before the refresh control goes away. That's not how I want it to work obviously, but perhaps I have coded it wrong.
viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView!.registerClass(PhotoBrowserCollectionViewCell.self, forCellWithReuseIdentifier: PhotoBrowserCellIdentifier)
self.cellLoadingIndicator.backgroundColor = goldenWordsYellow
self.cellLoadingIndicator.hidesWhenStopped = true
if self.revealViewController() != nil {
revealViewControllerIndicator = 1
menuButton.target = self.revealViewController()
menuButton.action = "revealToggle:"
self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
}
self.revealViewController().rearViewRevealWidth = 280
collectionView!.delegate = self
collectionView!.dataSource = self
goldenWordsRefreshControl = UIRefreshControl()
goldenWordsRefreshControl.backgroundColor = goldenWordsYellow
goldenWordsRefreshControl.tintColor = UIColor.whiteColor()
self.collectionView!.addSubview(goldenWordsRefreshControl)
navigationController?.setNavigationBarHidden(false, animated: true)
navigationItem.title = "Pictures"
setupView()
populatePhotos()
self.dateFormatter.dateFormat = "dd/MM/yy"
self.cellLoadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
self.cellLoadingIndicator.color = goldenWordsYellow
self.cellLoadingIndicator.center = (self.collectionView?.center)!
self.collectionView!.addSubview(cellLoadingIndicator)
self.collectionView!.bringSubviewToFront(cellLoadingIndicator)
/*
self.dateFormatter.dateStyle = NSDateFormatterStyle.ShortStyle
self.dateFormatter.timeStyle = NSDateFormatterStyle.ShortStyle
let currentDateAndTime = NSDate()
let updateString = "Last updated at " + self.dateFormatter.stringFromDate(currentDateAndTime)
self.goldenWordsRefreshControl.attributedTitle = NSAttributedString(string: updateString)
*/
}
populatePhotos:
func populatePhotos() {
if populatingPhotos {
return
}
populatingPhotos = true
self.cellLoadingIndicator.startAnimating()
self.temporaryPictureObjects.removeAllObjects()
Alamofire.request(GWNetworking.Router.Pictures(self.currentPage)).responseJSON() { response in
if let JSON = response.result.value {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)) {
var nodeIDArray : [Int]
if (JSON .isKindOfClass(NSDictionary)) {
for node in JSON as! Dictionary<String, AnyObject> {
let nodeIDValue = node.0
var lastItem : Int = 0
self.nodeIDArray.addObject(nodeIDValue)
if let pictureElement : PictureElement = PictureElement(title: "Picture", nodeID: 0, timeStamp: 0, imageURL: "http://goldenwords.ca/sites/all/themes/custom/gw/logo.png", author: "Staff", issueNumber: "Issue # error", volumeNumber: "Volume # error") {
pictureElement.title = node.1["title"] as! String
pictureElement.nodeID = Int(nodeIDValue)!
let timeStampString = node.1["revision_timestamp"] as! String
pictureElement.timeStamp = Int(timeStampString)!
if let imageURL = node.1["image_url"] as? String {
pictureElement.imageURL = imageURL
}
if let author = node.1["author"] as? String {
pictureElement.author = author
}
if let issueNumber = node.1["issue_int"] as? String {
pictureElement.issueNumber = issueNumber
}
if let volumeNumber = node.1["volume_int"] as? String {
pictureElement.volumeNumber = volumeNumber
}
lastItem = self.temporaryPictureObjects.count // Using a temporary set to not handle the dataSource set directly (safer).
self.temporaryPictureObjects.addObject(pictureElement)
let indexPaths = (lastItem..<self.temporaryPictureObjects.count).map { NSIndexPath(forItem: $0, inSection: 0) }
}
}
/* Sorting the elements in order of newest to oldest (as the array index increases] */
let timeStampSortDescriptor = NSSortDescriptor(key: "timeStamp", ascending: false)
self.pictureObjects.sortUsingDescriptors([timeStampSortDescriptor])
}
dispatch_async(dispatch_get_main_queue()) {
self.pictureObjects = self.temporaryPictureObjects
self.collectionView!.reloadData()
self.cellLoadingIndicator.stopAnimating()
self.currentPage++
self.populatingPhotos = false
}
}
}
}
}
handleRefresh:
func handleRefresh() {
goldenWordsRefreshControl.beginRefreshing()
self.pictureObjects.removeAllObjects()
self.currentPage = 0
self.cellLoadingIndicator.startAnimating()
self.picturesCollectionView.bringSubviewToFront(cellLoadingIndicator)
self.populatingPhotos = false
populatePhotos()
self.cellLoadingIndicator.stopAnimating()
goldenWordsRefreshControl.endRefreshing()
}
cellForItemAtIndexPath:
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(PhotoBrowserCellIdentifier, forIndexPath: indexPath) as! PhotoBrowserCollectionViewCell
if let pictureObject = pictureObjects.objectAtIndex(indexPath.row) as? PictureElement {
let title = pictureObject.title ?? "" // if pictureObject.title == nil, then we return an empty string
let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(pictureObject.timeStamp))
let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)
let author = pictureObject.author ?? ""
let issueNumber = pictureObject.issueNumber ?? ""
let volumeNumber = pictureObject.volumeNumber ?? ""
let nodeID = pictureObject.nodeID ?? 0
let imageURL = pictureObject.imageURL ?? "http://goldenwords.ca/sites/all/themes/custom/gw/logo.png"
cell.request?.cancel()
if let image = self.imageCache.objectForKey(imageURL) as? UIImage {
cell.imageView.image = image
} else {
cell.imageView.image = nil
cell.request = Alamofire.request(.GET, imageURL).responseImage() { response in
if let image = response.result.value {
self.imageCache.setObject(response.result.value!, forKey: imageURL)
if cell.imageView.image == nil {
cell.imageView.image = image
}
}
}
}
}
return cell
}