In-App purchase is used to purchase additional content or upgrade features with respect to an application.

Steps Involved

Step 1 − In iTunes connect, ensure that you have a unique App ID and when we create the application update with the bundle ID and code signing in Xcode with corresponding provisioning profile.

Step 2 − Create a new application and update application information. You can know more about this in apple”s Add new apps documentation.

Step 3 − Add a new product for in-app purchase in Manage In-App Purchase of your application”s page.

Step 4 − Ensure you setup the bank details for your application. This needs to be setup for In-App purchase to work. Also, create a test user account using Manage Users option in iTunes connect page of your app.

Step 5 − The next steps are related to handling code and creating UI for our In-App purchase.

Step 6 − Create a single view application and enter the bundle identifier is the identifier specified in iTunes connect.

Step 7 − Update the ViewController.xib as shown below −

Step 8 − Create IBOutlets for the three labels and the button naming them as productTitleLabel, productDescriptionLabel, productPriceLabel and purchaseButton respectively.

Step 9 − Select your project file, then select targets and then add StoreKit.framework.

Step 10 − Update ViewController.h as follows −

#import <UIKit/UIKit.h>
#import <StoreKit/StoreKit.h>

@interface ViewController : UIViewController<
SKProductsRequestDelegate,SKPaymentTransactionObserver> {
   SKProductsRequest *productsRequest;
   NSArray *validProducts;
   UIActivityIndicatorView *activityIndicatorView;
   IBOutlet UILabel *productTitleLabel;
   IBOutlet UILabel *productDescriptionLabel;
   IBOutlet UILabel *productPriceLabel;
   IBOutlet UIButton *purchaseButton;
}

- (void)fetchAvailableProducts;
- (BOOL)canMakePurchases;
- (void)purchaseMyProduct:(SKProduct*)product;
- (IBAction)purchase:(id)sender;

@end

Step 11 − Update ViewController.m as follows −

#import "ViewController.h"
#define kTutorialPointProductID 
@"com.tutorialPoints.testApp.testProduct"

@interface ViewController ()
@end

@implementation ViewController

- (void)viewDidLoad {
   [super viewDidLoad];
   
   // Adding activity indicator
   activityIndicatorView = [[UIActivityIndicatorView alloc]
   initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
   activityIndicatorView.center = self.view.center;
   [activityIndicatorView hidesWhenStopped];
   [self.view addSubview:activityIndicatorView];
   [activityIndicatorView startAnimating];
   
   //Hide purchase button initially
   purchaseButton.hidden = YES;
   [self fetchAvailableProducts];
}

- (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
   // Dispose of any resources that can be recreated.
}

-(void)fetchAvailableProducts {
   NSSet *productIdentifiers = [NSSet 
   setWithObjects:kTutorialPointProductID,nil];
   productsRequest = [[SKProductsRequest alloc] 
   initWithProductIdentifiers:productIdentifiers];
   productsRequest.delegate = self;
   [productsRequest start];
}

- (BOOL)canMakePurchases {
   return [SKPaymentQueue canMakePayments];
}

- (void)purchaseMyProduct:(SKProduct*)product {
   if ([self canMakePurchases]) {
      SKPayment *payment = [SKPayment paymentWithProduct:product];
      [[SKPaymentQueue defaultQueue] addTransactionObserver:self];
      [[SKPaymentQueue defaultQueue] addPayment:payment];
   } else {
      UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:
      @"Purchases are disabled in your device" message:nil delegate:
      self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
      [alertView show];
   }
}
-(IBAction)purchase:(id)sender {
   [self purchaseMyProduct:[validProducts objectAtIndex:0]];
   purchaseButton.enabled = NO; 
}

#pragma mark StoreKit Delegate

-(void)paymentQueue:(SKPaymentQueue *)queue 
updatedTransactions:(NSArray *)transactions {
   for (SKPaymentTransaction *transaction in transactions) {
      switch (transaction.transactionState) {
         case SKPaymentTransactionStatePurchasing:
            NSLog(@"Purchasing");
         break;
         
         case SKPaymentTransactionStatePurchased:
            if ([transaction.payment.productIdentifier 
            isEqualToString:kTutorialPointProductID]) {
               NSLog(@"Purchased ");
               UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:
               @"Purchase is completed succesfully" message:nil delegate:
               self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
               [alertView show];
            }
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
         break;
            
         case SKPaymentTransactionStateRestored:
            NSLog(@"Restored ");
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
         break;
            
         case SKPaymentTransactionStateFailed:
            NSLog(@"Purchase failed ");
         break
         default:
         break;
      }
   }
}

-(void)productsRequest:(SKProductsRequest *)request 
didReceiveResponse:(SKProductsResponse *)response {
   SKProduct *validProduct = nil;
   int count = [response.products count];
   
   if (count>0) {
      validProducts = response.products;
      validProduct = [response.products objectAtIndex:0];
      
      if ([validProduct.productIdentifier 
         isEqualToString:kTutorialPointProductID]) {
         [productTitleLabel setText:[NSString stringWithFormat:
            @"Product Title: %@",validProduct.localizedTitle]];
         [productDescriptionLabel setText:[NSString stringWithFormat:
            @"Product Desc: %@",validProduct.localizedDescription]];
         [productPriceLabel setText:[NSString stringWithFormat:
            @"Product Price: %@",validProduct.price]];
      }
   } else {
      UIAlertView *tmp = [[UIAlertView alloc]
         initWithTitle:@"Not Available"
         message:@"No products to purchase"
         delegate:self
         cancelButtonTitle:nil
         otherButtonTitles:@"Ok", nil];
         [tmp show];
   }
   
   [activityIndicatorView stopAnimating];
   purchaseButton.hidden = NO;
}
@end

Note

You have to update kTutorialPointProductID to the productID you have created for your In-App Purchase. You can add more than one product by updating the productIdentifiers”s NSSet in fetchAvailableProducts. Similary, handle the purchase related actions for product IDs you add.

Output

When we run the application, we”ll get the following output −

Ensure you had logged out of your account in the settings screen. On clicking the Initiate Purchase, select Use Existing Apple ID. Enter your valid test account username and password. You will be shown the following alert in a few seconds.

Once your product is purchased successfully, you will get the following alert. You can see relevant code for updating the application features where we show this alert.