     }
     
     
+    // MARK: Payment Transaction Observer Delegate Method
+    
+    func paymentQueue(queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
+        print("Purchase Made.")
+    }
+    
+    
     // MARK: Core Data Function
     
     func createArt(title: String, imageName: String, productIdentifier: String, purchased: Bool) {

import StoreKit


class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, SKProductsRequestDelegate {

    @IBOutlet weak var collectionView: UICollectionView!
    

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.gallery.count
    }
    
    
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("ArtCollectionViewCell", forIndexPath: indexPath) as! ArtCollectionViewCell
