in-app purchase in Swift with a single product

Step 0: In your iTunes Connect account, create an In-App purchase.

For Single purchases, use this method:

1. Import

import StoreKit

2. Conform to StoreKit Delegate

class YOURViewController: UIViewController, SKProductsRequestDelegate, SKPaymentTransactionObserver {

3. Use a user default to track transactions

let defaults = NSUserDefaults.standardUserDefaults()

4. Product ID. This one will be same as in your iTunes Connect in app purchase

var product_id: NSString?override func viewDidLoad() {            product_id = "YOUR_PRODUCT_ID"    super.viewDidLoad()    SKPaymentQueue.defaultQueue().addTransactionObserver(self)    //Check if product is purchased    if (defaults.boolForKey("purchased")){         // Hide a view or show content depends on your requirement       overlayView.hidden = true         } else if (!defaults.boolForKey("stonerPurchased")) {        print("false")                }}

5. Unlock Content. This is button action which will initialize purchase

@IBAction func unlockAction(sender: AnyObject) {   print("About to fetch the products")   // We check that we are allow to make the purchase.   if (SKPaymentQueue.canMakePayments()) {        var productID:NSSet = NSSet(object: self.product_id!);        var productsRequest:SKProductsRequest = SKProductsRequest(productIdentifiers: productID);        productsRequest.delegate = self;        productsRequest.start();        println("Fetching Products");    } else {        print("can't make purchases");    }    }

6. Helper Methods

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

7. Delegate Methods for IAP

func productsRequest (request: SKProductsRequest, didReceiveResponse response: SKProductsResponse) {    var count : Int = response.products.count    if (count>0) {        var validProducts = response.products        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: [AnyObject]!)    {    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)                defaults.setBool(true , forKey: "purchased")                overlayView.hidden = true                break;            case .Failed:                print("Purchased Failed");                SKPaymentQueue.defaultQueue().finishTransaction(transaction as SKPaymentTransaction)                break;            case .Restored:                print("Already Purchased");                SKPaymentQueue.defaultQueue().restoreCompletedTransactions()                default:                break;            }        }    }        }

Swift > 3.0

import StoreKitclass YOURVIEWController:UIViewController, SKProductsRequestDelegate, SKPaymentTransactionObserver {let product_id: NSString = "com.some.inappid" // <!-- Change it to your inapp id

In your viewDidLoad add

override func viewDidLoad() {    super.viewDidLoad()    SKPaymentQueue.default().add(self)

In your buy button action

@IBAction func buyNowAction(_ sender: UIButton) {    if (SKPaymentQueue.canMakePayments()) {        let productID:NSSet = NSSet(array: [self.product_id as NSString]);        let productsRequest:SKProductsRequest = SKProductsRequest(productIdentifiers: productID as! Set<String>);        productsRequest.delegate = self;        productsRequest.start();        print("Fetching Products");    } else {        print("can't make purchases");    }}

In Your Restore button action

// MARK: - Restore In App Purchase    @IBAction func restoreAction(_ sender: UIButton) {    if (SKPaymentQueue.canMakePayments()) {        SKPaymentQueue.default().add(self)        SKPaymentQueue.default().restoreCompletedTransactions()    } else {        // show error    }}

Add Delegates:

// SKProductRequest Delegatefunc productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {    print(response.products)    let count : Int = response.products.count    if (count>0) {        let validProduct: SKProduct = response.products[0] as SKProduct        if (validProduct.productIdentifier == self.product_id as String) {            print(validProduct.localizedTitle)            print(validProduct.localizedDescription)            print(validProduct.price)            self.buyProduct(product: validProduct)        } else {            print(validProduct.productIdentifier)        }    } else {        print("nothing")    }}func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {    for transaction:AnyObject in transactions {        if let trans:SKPaymentTransaction = transaction as? SKPaymentTransaction{            self.dismissPurchaseBtn.isEnabled = true            self.restorePurchaseBtn.isEnabled = true            self.buyNowBtn.isEnabled = true            switch trans.transactionState {            case .purchased:                print("Product Purchased")                //Do unlocking etc stuff here in case of new purchase                SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)                break;            case .failed:                print("Purchased Failed");                SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)                break;            case .restored:                print("Already Purchased")                //Do unlocking etc stuff here in case of restor                SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)            default:                break;            }        }    }}//If an error occurs, the code will go to this function    func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {        // Show some alert    }

In app Purchas delegate Method :

func buyInApp(){    if (SKPaymentQueue.canMakePayments())    {        let productID:NSSet = NSSet(object: "com.valueedge.plane_post");        let productsRequest:SKProductsRequest = SKProductsRequest(productIdentifiers: productID as! Set<String>);        productsRequest.delegate = self;        productsRequest.start();    }    else    {        MBProgressHUD.hideHUDForView(self.view, animated: true)    }}func productsRequest (request: SKProductsRequest, didReceiveResponse response: SKProductsResponse){    let count : Int = response.products.count    if (count>0)    {        let validProduct: SKProduct = response.products[0] as SKProduct        if (validProduct.productIdentifier == "com.valueedge.plane_post")        {            buyProduct(validProduct);        }        else        {            MBProgressHUD.hideHUDForView(self.view, animated: true)        }    }    else    {        MBProgressHUD.hideHUDForView(self.view, animated: true)    }}func buyProduct(product: SKProduct){    let payment = SKPayment(product: product)    SKPaymentQueue.defaultQueue().addPayment(payment)    SKPaymentQueue.defaultQueue().addTransactionObserver(self)}func paymentQueue(queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]){    for transaction:AnyObject in transactions    {        if let trans:SKPaymentTransaction = transaction as? SKPaymentTransaction        {            switch trans.transactionState            {            case .Purchased:                self.PaymentSuccess("Apple", details: "Apple(In-App)")                print("In App Payment Success")                SKPaymentQueue.defaultQueue().finishTransaction(transaction as! SKPaymentTransaction)                MBProgressHUD.hideHUDForView(self.view, animated: true)                break            case .Failed:                MBProgressHUD.hideHUDForView(self.view, animated: true)                SKPaymentQueue.defaultQueue().finishTransaction(transaction as! SKPaymentTransaction)                let alert = UIAlertController(title: "Planes Only", message: "Payment failed", preferredStyle: .Alert)                alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: {(action:UIAlertAction!) in                }))                self.presentViewController(alert, animated: true, completion: nil)                break            case .Restored :                SKPaymentQueue.defaultQueue().finishTransaction(transaction as! SKPaymentTransaction)                MBProgressHUD.hideHUDForView(self.view, animated: true)                break            default:                MBProgressHUD.hideHUDForView(self.view, animated: true)                break            }        }    }}func restore(){    SKPaymentQueue.defaultQueue().addTransactionObserver(self)    SKPaymentQueue.defaultQueue().restoreCompletedTransactions()    MBProgressHUD.showHUDAddedTo(self.view, animated: true)}func paymentQueueRestoreCompletedTransactionsFinished(queue: SKPaymentQueue){    for transact:SKPaymentTransaction in queue.transactions    {        if transact.transactionState == SKPaymentTransactionState.Restored        {            //let t: SKPaymentTransaction = transact as SKPaymentTransaction            //let prodID = t.payment.productIdentifier as String            //restore prodID            SKPaymentQueue .defaultQueue().finishTransaction(transact)            MBProgressHUD.hideHUDForView(self.view, animated: true)        }    }}func paymentQueue(queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: NSError){    for transaction:SKPaymentTransaction  in queue.transactions    {        if transaction.transactionState == SKPaymentTransactionState.Restored        {            SKPaymentQueue.defaultQueue().finishTransaction(transaction)            MBProgressHUD.hideHUDForView(self.view, animated: true)            break        }    }    MBProgressHUD.hideHUDForView(self.view, animated: true)}func request(request: SKRequest, didFailWithError error: NSError){    MBProgressHUD.hideHUDForView(self.view, animated: true)}

In app button Clicked event :

@IBAction func In_App_Payment_Clicked(sender: AnyObject){    MBProgressHUD.showHUDAddedTo(self.view, animated: true)    self.buyInApp()}

For development in app purchase app even in simple way you need to resolve next subtasks which not relate to coding:

1. • Register as developer and creating an App ID under https://developer.apple.com/account/
   • select Certificates, IDs & Profiles.
   • select Identifiers > App IDs, and click + to create a new App ID.
   • make sure that In-App Purchase is enabled for your App ID.
2. • Fill out the agreement and bank info. For that login to https://itunesconnect.apple.com/
   • Important step - double check the Agreements, Tax, and Banking section. All of them should be filled out. In other case in app purchase will not work. You will get failed response from the server.
3. • Creating an App in iTunes Connect. For that just click to My Apps button under https://itunesconnect.apple.com/
   • Creating In-App Purchase Products. In your case Consumable or non Consumable. For managing Consumable or non Consumable code will be similar.
4. Create sandbox user or users. Creating an App in iTunes Connect. For that just go to https://itunesconnect.apple.com/ click to select Users and Roles button, then click the Sandbox Testers tab. Create the user-> and go to the test email and confirm user from email!
5. For starting the development and checking the connection between itunesconnect and your app you can use simulator. But when you will try to buy the product you need to use real device.
6. Mandatory for ios app with in app purchase to have not only buy button the "restore purchases" button should be developed too. (for example in Android app it is not mandatory, Android app check it in different way). In case if user remove his app and install it again he want to restore already purchases items. For that "restore purchases" should be developed.
7. • The last step is development and testing you can use next tutorial to get some useful example how to implement restore purchase button. - https://www.raywenderlich.com/122144/in-app-purchase-tutorial
   • Also listen some youtube video to make in app purchase more clearer for you - you can use next video which is really great - https://youtu.be/o3hJ0rY1NNw
   • That's it.