Why is my array out of bounds? - ios

Question

I am trying to incorporate an in-app purchase. For some reason I am getting a fatal error that states 'fatal error: Index out of range' with an array that holds the SKProduct products. I have one nonconsumable in app purchase, but may decide to add more later. I am trying to access the PREMIUM_PRODUCT_ID product so I can make a purchase. The error occurs when the purchaseMyProduct function is called. Any ideas in why the iapProducts array is out of bounds? Thanks for your help!
The fatal error occurs on this line purchaseMyProduct(product: iapProducts[0])
import UIKit
import StoreKit
class Settings: UIViewController, SKProductsRequestDelegate,
SKPaymentTransactionObserver {
let PREMIUM_PRODUCT_ID = "---------------"
var productID = ""
var productsRequest = SKProductsRequest()
var iapProducts = [SKProduct]()
var nonConsumablePurchaseMade = UserDefaults.standard.bool(forKey: "nonConsumablePurchaseMade")
#IBOutlet weak var adsBtn: UIButton!
#IBAction func restorePurchase(_ sender: Any) {
SKPaymentQueue.default().add(self)
SKPaymentQueue.default().restoreCompletedTransactions()
// Check your In-App Purchases
print("NON CONSUMABLE PURCHASE MADE: \(nonConsumablePurchaseMade)")
// Fetch IAP Products available
fetchAvailableProducts()
UIAlertView(title: "IAP Tutorial",
message: "You've successfully restored your purchase!",
delegate: nil, cancelButtonTitle: "OK").show()
}
#IBAction func review(_ sender: Any) {
UIApplication.shared.openURL(NSURL(string: "-----------------")! as URL)
}
#IBAction func removeAds(_ sender: Any) {
//UIApplication.shared.openURL(NSURL(string: "----------------")! as URL)
purchaseMyProduct(product: iapProducts[0])
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
...
func paymentQueueRestoreCompletedTransactionsFinished(_ queue: SKPaymentQueue) {
nonConsumablePurchaseMade = true
UserDefaults.standard.set(nonConsumablePurchaseMade, forKey: "nonConsumablePurchaseMade")
/*UIAlertView(title: "IAP Tutorial",
message: "You've successfully restored your purchase!",
delegate: nil, cancelButtonTitle: "OK").show()*/
}
func fetchAvailableProducts() {
// Put here your IAP Products ID's
let productIdentifiers = NSSet(objects:
PREMIUM_PRODUCT_ID
)
productsRequest = SKProductsRequest(productIdentifiers: productIdentifiers as! Set<String>)
productsRequest.delegate = self
productsRequest.start()
}
func productsRequest (_ request:SKProductsRequest, didReceive response:SKProductsResponse) {
if (response.products.count > 0) {
iapProducts = response.products
// 1st IAP Product (Consumable) ------------------------------------
let firstProduct = response.products[0] as SKProduct
// Get its price from iTunes Connect
let numberFormatter = NumberFormatter()
numberFormatter.formatterBehavior = .behavior10_4
numberFormatter.numberStyle = .currency
numberFormatter.locale = firstProduct.priceLocale
let price1Str = numberFormatter.string(from: firstProduct.price)
// Show its description
//consumableLabel.text = firstProduct.localizedDescription + "\nfor just \(price1Str!)"
// ------------------------------------------------
// 2nd IAP Product (Non-Consumable) ------------------------------
let secondProd = response.products[0] as SKProduct
// Get its price from iTunes Connect
numberFormatter.locale = secondProd.priceLocale
let price2Str = numberFormatter.string(from: secondProd.price)
// Show its description
//nonConsumableLabel.text = secondProd.localizedDescription + "\nfor just \(price2Str!)"
// ------------------------------------
}
}
func canMakePurchases() -> Bool { return SKPaymentQueue.canMakePayments() }
func purchaseMyProduct(product: SKProduct) {
if self.canMakePurchases() {
let payment = SKPayment(product: product)
SKPaymentQueue.default().add(self)
SKPaymentQueue.default().add(payment)
print("PRODUCT TO PURCHASE: \(product.productIdentifier)")
productID = product.productIdentifier
// IAP Purchases dsabled on the Device
} else {
UIAlertView(title: "IAP Tutorial",
message: "Purchases are disabled in your device!",
delegate: nil, cancelButtonTitle: "OK").show()
}
}
func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
for transaction:AnyObject in transactions {
if let trans = transaction as? SKPaymentTransaction {
switch trans.transactionState {
case .purchased:
SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
// The Consumable product (10 coins) has been purchased -> gain 10 extra coins!
if productID == PREMIUM_PRODUCT_ID {
// Save your purchase locally (needed only for Non-Consumable IAP)
nonConsumablePurchaseMade = true
UserDefaults.standard.set(nonConsumablePurchaseMade, forKey: "nonConsumablePurchaseMade")
//premiumLabel.text = "Premium version PURCHASED!"
UIAlertView(title: "IAP Tutorial",
message: "You've successfully unlocked the Premium version!",
delegate: nil,
cancelButtonTitle: "OK").show()
}
break
case .failed:
SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
break
case .restored:
SKPaymentQueue.default().finishTransaction(transaction as! SKPaymentTransaction)
break
default: break
}}}
}
}

Answer 1

Your code is way too long, so I took the liberty of making an educated guess what is relevant:
import UIKit
import StoreKit
class Settings: UIViewController, SKProductsRequestDelegate,
SKPaymentTransactionObserver {
var iapProducts = [SKProduct]()
#IBAction func removeAds(_ sender: Any) {
purchaseMyProduct(product: iapProducts[0])
}
}
When you declare iapProducts, you are creating an empty array that contains no values.
Then, in your removeAds function, you are telling it to do something with the first element.
I am going to take a wild guess that nothing exists, so you are forcing it to access an object that doesn't exist.
Try the following and see if it fixes your issue.
var iapProducts: [SKProduct]?
#IBAction func removeAds(_ sender: Any) {
guard let product = iapProducts?.first else { return }
purchaseMyProduct(product: product)
}
This accomplishes two things:
It makes your [SKProduct] array an optional
The guard statement safely unwraps the first product, so only if one exists, will it try to call your purchaseMyProduct function. Otherwise, it just exits