# In-App Purchase

# Single IAP in Swift 2

After creating an IAP in iTunesConnect:

In the view controller that you want to buy in

import StoreKit

and add the relevant delegates

class ViewController: UIViewController, SKProductsRequestDelegate, SKPaymentTransactionObserver {

declare a variable with the product id from iTunesConnect

var product_id: NSString?

override func viewDidLoad() {
    
    
    product_id = "YOUR_PRODUCT_ID"
    super.viewDidLoad()
    SKPaymentQueue.defaultQueue().addTransactionObserver(self)

   //Check if product is purchased
   if (NSUserDefaults.standardUserDefaults().boolForKey("purchased")){
   
       // Hide ads
       adView.hidden = true
        
   } else {
       print("Should show ads...")
        
   }

}

wire a button to a function to purchase the IAP

@IBAction func unlockAction(sender: AnyObject) {
    
   print("About to fetch the product...")

// Can make payments
if (SKPaymentQueue.canMakePayments())
    {
        let productID:NSSet = NSSet(object: self.product_id!);
        let productsRequest:SKProductsRequest = SKProductsRequest(productIdentifiers: productID as! Set<NSString>);
        productsRequest.delegate = self;
        productsRequest.start();
        println("Fetching Products");
    }else{
        print("Can't make purchases");
    }

}

And here are some helper methods

func buyProduct(product: SKProduct){
    println("Sending the Payment Request to Apple");
    let payment = SKPayment(product: product)
    SKPaymentQueue.defaultQueue().addPayment(payment);
    
 }

the delegate methods that must be declared

func productsRequest (request: SKProductsRequest, didReceiveResponse response: SKProductsResponse) {

    let count : Int = response.products.count
    if (count>0) {
        var validProduct: SKProduct = response.products[0] as SKProduct
        if (validProduct.productIdentifier == self.product_id) {
            print(validProduct.localizedTitle)
            print(validProduct.localizedDescription)
            print(validProduct.price)
            buyProduct(validProduct);
        } else {
            print(validProduct.productIdentifier)
        }
    } else {
        print("nothing")
    }
}


func request(request: SKRequest!, didFailWithError error: NSError!) {
    print("Error Fetching product information");
}

    func paymentQueue(_ queue: SKPaymentQueue,
updatedTransactions transactions: [SKPaymentTransaction])

{
    print("Received Payment Transaction Response from Apple");
    
    for transaction:AnyObject in transactions {
        if let trans:SKPaymentTransaction = transaction as? SKPaymentTransaction{
            switch trans.transactionState {
            case .Purchased:
                print("Product Purchased");
                SKPaymentQueue.defaultQueue().finishTransaction(transaction as! SKPaymentTransaction)
                // Handle the purchase
                NSUserDefaults.standardUserDefaults().setBool(true , forKey: "purchased")
                adView.hidden = true
                break;
            case .Failed:
                print("Purchased Failed");
                SKPaymentQueue.defaultQueue().finishTransaction(transaction as! SKPaymentTransaction)
                break;
                
        

            case .Restored:
                print("Already Purchased");
               SKPaymentQueue.defaultQueue().restoreCompletedTransactions() 


                 // Handle the purchase
                    NSUserDefaults.standardUserDefaults().setBool(true , forKey: "purchased")
                    adView.hidden = true
                    break;
            default:
                break;
            }
        }
    }
    
}

And then the code to restore a non-consumable in app purchase

if (SKPaymentQueue.canMakePayments()) {
  SKPaymentQueue.defaultQueue().restoreCompletedTransactions()
}

# Set Up in iTunesConnect

In iTunesConnect, select the app which you want to add an IAP to.

Click on features and you will see this:

enter image description here

Click the plus. You will then need to select which type of IAP you want to make.

Then you will need to fill out all of the information for your IAP.

enter image description here

If you have any trouble you can consult the IAP Set Up Guide.

# Most basic steps for purchasing/subscribing a user to an IAP

Assuming you know the productID:

First

import StoreKit

Then in your code

let productID: Set = ["premium"]
let request = SKProductsRequest(productIdentifiers: productID)
request.delegate = self
request.start()

and in the SKProductsRequestDelegate:

func productsRequest(request: SKProductsRequest, didReceiveResponse response: SKProductsResponse) {
    if response.products.count > 0 {
        let product = response.products[0]
        let payment = SKPayment(product: product)
        SKPaymentQueue.defaultQueue().addPayment(payment)
    }
}