I am writing my first iOS app in Swift and have been having some problems with the in-app purchases functionality. I think I've got the actual buy function working but I'm not sure about the restore functionality. I'm just providing one product which is a 'pro' version of the app. This is stored in the User Defaults location and having it unlocks the extra functionality. My restore function is confusing me, can someone have a look at it and tell me where I should be setting my User Defaults value? Should it be within the paymentQueueRestoreCompletedTransactionsFinished function or the paymentQueue function?
import UIKit
import StoreKit
class StoreController: UIViewController, SKProductsRequestDelegate,
SKPaymentTransactionObserver {
// Properties
var defaults = UserDefaults.standard
var list = [SKProduct]()
var p = SKProduct()
// Methods
override func viewDidLoad() {
super.viewDidLoad()
// Get list of products for the store
localTitle.isEnabled = false
localDescription.isEnabled = false
price.isEnabled = false
buy.isEnabled = false
restore.isEnabled = false
getProducts()
}
// Outlets
@IBOutlet weak var localTitle: UILabel!
@IBOutlet weak var localDescription: UILabel!
@IBOutlet weak var price: UILabel!
@IBOutlet weak var buy: UIButton!
@IBOutlet weak var restore: UIButton!
// Actions
@IBAction func buy(_ sender: UIButton) {
print("buy pressed")
for product in list {
let prodID = product.productIdentifier
if(prodID == "com.squidgylabs.pro") {
p = product
buyProduct()
}
}
}
@IBAction func restore(_ sender: UIButton) {
print("restore pressed")
SKPaymentQueue.default().add(self)
SKPaymentQueue.default().restoreCompletedTransactions()
}
// Methods
func getProducts() {
print("starting getproducts function")
if(SKPaymentQueue.canMakePayments()) {
print("IAP is enabled, loading")
let productID: NSSet = NSSet(objects: "com.squidgylabs.pro")
let request: SKProductsRequest = SKProductsRequest(productIdentifiers: productID as! Set<String>)
request.delegate = self
request.start()
} else {
print("please enable IAPS")
}
}
func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
print("starting productsrequest")
let myProduct = response.products
for product in myProduct {
print("product added")
list.append(product)
}
localTitle.isEnabled = true
localDescription.isEnabled = true
restore.isEnabled = true
buy.isEnabled = true
price.isEnabled = true
// Update labels
localTitle.text = list[0].localizedTitle
localDescription.text = list[0].localizedDescription
// Format the price and display
let formatter = NumberFormatter()
formatter.locale = Locale.current
formatter.numberStyle = .currency
if let formattedPrice = formatter.string(from: list[0].price){
price.text = formattedPrice
}
}
func paymentQueueRestoreCompletedTransactionsFinished(_ queue: SKPaymentQueue) {
print("starting paymentQueueResoreCompletedTransactionsFnished")
for transaction in queue.transactions {
let t: SKPaymentTransaction = transaction
let prodID = t.payment.productIdentifier as String
switch prodID {
case "com.squidgylabs.pro":
print("case is correct product ID in payment...finished")
default:
print("IAP not found")
}
}
}
func buyProduct() {
print("buy " + p.productIdentifier)
let pay = SKPayment(product: p)
SKPaymentQueue.default().add(self)
SKPaymentQueue.default().add(pay as SKPayment)
}
func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
print("entering func paymentQueue")
for transaction: AnyObject in transactions {
let trans = transaction as! SKPaymentTransaction
switch trans.transactionState {
case .purchased:
print("buy ok, unlock IAP HERE")
print(p.productIdentifier)
let prodID = p.productIdentifier
switch prodID {
case "com.squidgylabs.pro":
print("setting pro in defaults...")
defaults.set(true, forKey: "pro")
default:
print("IAP not found")
}
queue.finishTransaction(trans)
break
case .failed:
print("buy error")
queue.finishTransaction(trans)
break
case .restored:
print("case .restored in paymentQ")
SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
queue.finishTransaction(trans)
break
default:
print("Default")
break
}
}
}
}
It may be done like this.
public func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
for transaction in transactions {
switch transaction.transactionState {
case .purchased:
completePurchaseForTransaction(transaction)
case .restored:
completePurchaseForTransaction(transaction)
default:
break
}
}
private func completePurchaseForTransaction(_ transaction: SKPaymentTransaction) {
let productIdentifier = transaction.payment.productIdentifier
// Update UserDefaults here
SKPaymentQueue.default().finishTransaction(transaction)
}
You might consider using other class for StoreKit access instead of a UIViewController. Because
Your application should always expect to be notified of completed transactions.
https://developer.apple.com/documentation/storekit/skpaymentqueue/1506042-add
And View controllers come and go. It might even crash the app if you don't remove object you added as an observer to the SKPaymentQueue.
I have simple, well-documented StoreKit library on GitHub that you might check out to get the idea -- https://github.com/suvov/VSStoreKit