In App Purchase - App crash sometimes - ios

Question

I'm looking through the internet for days already and can not find solution to my problem. I have created an app and want you to remove the advertising through an in app purchase. My problem is that the app sometimes crashes when I click on the button "BuyProduct". I then get the error message "Thread 1: EXC_BAD_ACCESS (code = 1, address = 0x16e6f6980)" after the line [[SKPaymentQueue defaultQueue] addPayment:payment];.
Here my .h of my PurchasedViewController:
​#import <UIKit/UIKit.h>
#import <StoreKit/StoreKit.h>
#interface PurchasedViewController2 : UIViewController <SKPaymentTransactionObserver, SKProductsRequestDelegate>{
NSTimer *myTimer;
int countdown;
}
#property (strong, nonatomic) SKProduct *product;
#property (strong, nonatomic) NSString *productID;
#property (strong, nonatomic) IBOutlet UILabel *productTitle;
#property (strong, nonatomic) IBOutlet UITextView *productDescription;
#property (strong, nonatomic) IBOutlet UIButton *buyButton;
#property (weak, nonatomic) IBOutlet UIButton *goBack;
#property (weak, nonatomic) IBOutlet UILabel *labelGray;
#property (weak, nonatomic) IBOutlet UILabel *labelCountdown;
- (IBAction)GoBack:(id)sender;
- (IBAction)BuyProduct:(id)sender;
- (IBAction)Restore:(id)sender;
-(void)getProductID:(UIViewController *)viewController;
-(void)UnlockPurchase;
-(void)update;
#end
here the .m
​#import "PurchasedViewController2.h"
#import "ViewController.h"
#interface PurchasedViewController2 ()
#property (strong, nonatomic) ViewController *homeViewController;
#end
#implementation PurchasedViewController2
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
countdown = 5;
_labelCountdown.text = [NSString stringWithFormat:#"%i",countdown];
_goBack.enabled = FALSE;
myTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(update) userInfo:nil repeats:YES];
// Do any additional setup after loading the view.
}
-(void)update{
countdown--;
if (countdown >=0) {
_labelCountdown.text = [NSString stringWithFormat:#"%i",countdown];
}
if (countdown <=0) {
_labelCountdown.hidden = TRUE;
_labelGray.hidden = TRUE;
_goBack.enabled = TRUE;
[myTimer invalidate];
}
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
- (IBAction)GoBack:(id)sender {
[self dismissViewControllerAnimated:YES completion:NULL];
}
- (IBAction)BuyProduct:(id)sender {
SKPayment *payment = [SKPayment paymentWithProduct:_product];
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
[[SKPaymentQueue defaultQueue] addPayment:payment];
}
-(void)viewDidUnload{
[[SKPaymentQueue defaultQueue]removeTransactionObserver:self];
[super viewDidUnload];
}
- (IBAction)Restore:(id)sender {
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
[[SKPaymentQueue defaultQueue] restoreCompletedTransactions];
}
-(void)paymentQueueRestoreCompletedTransactionsFinished:(SKPaymentQueue *)queue{
[self UnlockPurchase];
}
-(void)getProductID:(ViewController *)viewController{
_homeViewController = viewController;
if ([SKPaymentQueue canMakePayments]) {
SKProductsRequest *request = [[SKProductsRequest alloc] initWithProductIdentifiers:[NSSet setWithObject:self.productID]];
request.delegate = self;
[request start];
}
else{
_productDescription.text = #"Please enable in app purchase in your setting";
}
}
#pragma mark _
#pragma mark SKProductsRequestDelegate
-(void) productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response{
NSArray *products = response.products;
if (products.count != 0) {
_product = products[0];
_buyButton.enabled = YES;
_productTitle.text = _product.localizedTitle;
_productDescription.text = _product.localizedDescription;
}
else{
_productTitle.text = #"Product Not Found";
}
products = response.invalidProductIdentifiers;
for (SKProduct *product in products) {
NSLog(#"Product not Found: %#", product);
}
}
-(void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions {
for (SKPaymentTransaction *transaction in transactions) {
switch (transaction.transactionState) {
case SKPaymentTransactionStatePurchased:[self UnlockPurchase];
[[SKPaymentQueue defaultQueue] finishTransaction:transaction];
break;
case SKPaymentTransactionStateFailed:NSLog(#"Transaction Failed");
[[SKPaymentQueue defaultQueue] finishTransaction:transaction];
default:
break;
}
}
}
-(void)UnlockPurchase{
_buyButton.enabled = NO;
[_buyButton setTitle:#"Purchased" forState:UIControlStateDisabled];
[_homeViewController Purchased];
}
#end
and here is my call of the view:
​- (IBAction)PurchaseItem:(id)sender {
_purchaseController = [[PurchasedViewController2 alloc] initWithNibName:nil bundle:nil];
_purchaseController.productID =#"PS.PileUp.RemoveAds";
[[SKPaymentQueue defaultQueue] addTransactionObserver:_purchaseController];
[self presentViewController:_purchaseController animated:YES completion:NULL];
[_purchaseController getProductID:self];
}
Thank you very munch

Answer 1

Thx i solve it. I change the GoBack Method to:
- (IBAction)GoBack:(id)sender {
[[SKPaymentQueue defaultQueue]removeTransactionObserver:self];
[self dismissViewControllerAnimated:YES completion:NULL];
}

Answer 2

It looks like you have a race condition between pressing the BuyProduct button and creation of the _product. In general, you should be finished the SKProductsRequest before allowing the user to tap BuyProduct. That is, do you know _product has the value you want when BuyProduct is pressed?