In-App Purchase

In-App Purchases


In-App Purchases: How to implement a space shooter with SpriteKit and SWIFT – Part 8

 
 

 

 

Tutorial Overview: How to implement a space shooter with SpriteKit and SWIFT

  • Part 1: Initial project setup, sprite creation and movement using SKAction and SKConstraint
  • Part 2: Adding enemies, bullets and shooting with SKAction and SKConstraint
  • Part 3: Adding a HUD with SKLabelNode and SKSpriteNode
  • Part 4: Adding basic game logic and collision detection
  • Part 5: Adding particles and sound 
  • Part 6: GameCenter integration
  • Part 7: iAd integration
  • Part 8: In-App Purchases

Adding In-App Purchases:

Welcome to part 8 of my swift programming tutorial. Today I’ll show how to implement In-App Purchases:

InApp01 InApp02

 

As a starting point you can download the sample project from my GitHub repository.  

Let’s start:

1. Create In-App Purchases in iTunes Connect

You need a paid Apple Developer Account to execute the next steps. For details about the process to upload Apps to iTunes Connect check tutorial part 6.

  Browse to iTunes Connect and open your App: InApp2 Choose In-App Purchases and click on Create New: InApp3 You see several different types of possible purchases. In this tutorial I’ll show a ‚Consumable‚ and a ‚Non-Consumable‚ purchase. InApp4 Create the Consumable purchase: InApp5 Enter Reference NameProduct ID and Price Tier: InApp6 Add Display Name and Description at least for one language: InApp7 Additionally a screenshot is needed for the review team: InApp8 Now do the same for the Non-Consumable purchase: InApp9 InApp14 The final result should look like this: InApp15  

2. Implement In-App Purchases

Open your project in XCode (sample project is available here), navigate to the Capabilities configuration page and enable In-App Purchases: InApp12 Xcode will include the StoreKit framework and add the In-App Purchase entitlement automatically.

2.1. Add a button to trigger the purchases:

Open the createHUD method in GameScene.swift and add this code snippet to add a ‚$$$‘ button to the header: InApp13

 
 
 
func createHUD() {
 
        …
 
        // Add a $ Button for In-App Purchases:
        var purchaseButton = SKLabelNode()
        purchaseButton.position = CGPointMake(hud.size.width/1.5, 1)
        purchaseButton.text=„$$$“
        purchaseButton.fontSize=hud.size.height
        purchaseButton.horizontalAlignmentMode = SKLabelHorizontalAlignmentMode.Center
        purchaseButton.name=„PurchaseButton“

Add these two lines to touchesBegan to call inAppPurchase:

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        /* Called when a touch begins */
 
        for touch in (touches as! Set<UITouch>) {
            var location = touch.locationInNode(self)
            var node = self.nodeAtPoint(location)
            if (node.name == „PauseButton“) || (node.name == „PauseButtonContainer“) {
              showPauseAlert()
            } else if (node.name == „PurchaseButton“) {
                inAppPurchase()
            } else {
            …

Add an empty inAppPurchase method:

    func inAppPurchase() {
    }

2.2. Implement Puchase

All changes will be done in GameScene.swift. Import the StoreKit framework: import StoreKit Add the StoreKit protocols:

class GameScene: SKScene, SKPhysicsContactDelegatee, SKPaymentTransactionObserver, SKProductsRequestDelegate  {

Add these lines at the end of the didMoveToView method to initialise the purchase objects and to check if the new feature is already purchased:

// In-App Purchase
initInAppPurchases()
checkAndActivateGreenShip()

I’ve documented the missing methods in the code itself:

    // ———————————
    // —- Handle In-App Purchases —-
    // ———————————
 
    private var request : SKProductsRequest!
    private var products : [SKProduct] = [] // List of available purchases
    private var greenShipPurchased = false // Used to enable/disable the ‚green ship‘ feature
 
    // Open a menu with the available purchases
    func inAppPurchase() {
 
        var alert = UIAlertController(title: „In App Purchases“, message: „“, preferredStyle: UIAlertControllerStyle.Alert)
 
        self.gamePaused = true
 
        // Add an alert action for each available product
        for (var i = 0; i < products.count; i++) {
 
            var currentProduct = products[i]
            if !(currentProduct.productIdentifier == „MySecondGameGreenShip“ && greenShipPurchased) {
 
                // Get the localized price
                let numberFormatter = NSNumberFormatter()
                numberFormatter.numberStyle = .CurrencyStyle
                numberFormatter.locale = currentProduct.priceLocale
 
                // Add the alert action
                alert.addAction(UIAlertAction(title: currentProduct.localizedTitle + “ „ + numberFormatter.stringFromNumber(currentProduct.price)!, style: UIAlertActionStyle.Default)  { _ in
 
                    // Perform the purchase
                    self.buyProduct(currentProduct)
                    self.gamePaused = false
                    })
            }
        }
 
        // Offer the restore option only if purchase info is not available
        if(greenShipPurchased == false) {
            alert.addAction(UIAlertAction(title: „Restore“, style: UIAlertActionStyle.Default)  { _ in
                self.restorePurchasedProducts()
                self.gamePaused = false
                })
        }
 
        alert.addAction(UIAlertAction(title: „Cancel“, style: UIAlertActionStyle.Default) { _ in
            self.gamePaused = false
            })
 
        // Show the alert
        self.view?.window?.rootViewController?.presentViewController(alert, animated: true, completion: nil)
    }
 
    // Initialize the App Purchases
    func initInAppPurchases() {
        SKPaymentQueue.defaultQueue().addTransactionObserver(self)
 
        // Get the list of possible purchases
        if self.request == nil {
            self.request = SKProductsRequest(productIdentifiers: Set([„MySecondGameGreenShip“,„MySecondGameDonate“]))
            self.request.delegate = self
            self.request.start()
        }
    }
 
    // Request a purchase
    func buyProduct(product: SKProduct) {
        let payment = SKPayment(product: product)
        SKPaymentQueue.defaultQueue().addPayment(payment)
    }
 
    // Restore purchases
    func restorePurchasedProducts() {
        SKPaymentQueue.defaultQueue().restoreCompletedTransactions()
    }
 
    // StoreKit protocoll method. Called when the AppStore responds
    func productsRequest(request: SKProductsRequest!, didReceiveResponse response: SKProductsResponse!) {
        self.products = response.products as! [SKProduct]
        self.request = nil
    }
 
    // StoreKit protocoll method. Called when an error happens in the communication with the AppStore
    func request(request: SKRequest!, didFailWithError error: NSError!) {
        println(error)
        self.request = nil
    }
 
    // StoreKit protocoll method. Called after the purchase
    func paymentQueue(queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!) {
 
        for transaction in transactions as! [SKPaymentTransaction] {
            switch (transaction.transactionState) {
 
            case .Purchased:
                if transaction.payment.productIdentifier == „MySecondGameGreenShip“ {
                    handleGreenShipPurchased()
                }
                queue.finishTransaction(transaction)
 
            case .Restored:
                if transaction.payment.productIdentifier == „MySecondGameGreenShip“ {
                    handleGreenShipPurchased()
                }
                queue.finishTransaction(transaction)
 
            case .Failed:
                println(„Payment Error: %@“, transaction.error)
                queue.finishTransaction(transaction)
            default:
                println(„Transaction State: %@“, transaction.transactionState)
            }
        }
    }
 
    // Called after the purchase to provide the ‚green ship‘ feature
    func handleGreenShipPurchased() {
        greenShipPurchased = true
        checkAndActivateGreenShip()
        // persist the purchase locally
        NSUserDefaults.standardUserDefaults().setBool(true, forKey: „MySecondGameGreenShip“)
    }
 
    // Called after applicattion start to check if the ‚green ship‘ feature was purchased
    func checkAndActivateGreenShip() {
        if NSUserDefaults.standardUserDefaults().boolForKey(„MySecondGameGreenShip“) {
            greenShipPurchased = true
            heroSprite.color = UIColor.greenColor()
            heroSprite.colorBlendFactor=0.8
        }
    }
 

Test and upload to iTunes Connect

You need a Sandbox Test User to test the purchases. I’ve described the steps to create one in part 6. InApp16

  Testing is only possible on a real device. If you try a purchase in the simulator, you’ll receive an error message: AppStore is not available. And don’t forget to set the checkmarks on your purchases to include them to your them to your application bundle, before submitting  a new version in iTunesConnect.  

That’s all for today. The SourceCode of this tutorial is available at GitHubTo see In-App Purchase in action you can download my free game in the AppStore. The In-App Purchase update will be released in the next days.
 
 

Cheers,
Stefan

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