Detect Cancel Button Tap for "Confirm Your In-App Purchase" UIAlert - iphone

Question

I implemented in-app purchase based on this tutorial. The problem I experience is that I cannot detect when Cancel button is pressed on the "Confirm Your In-App Purchase" alert, which is a part of StoreKit framework.
Some sources suggest -(void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions is called when Cancel is pressed but in my case it never runs. My set up is the ViewController which imports IAPManager:NSObject class which conforms to SKProductRequestDelegate and SKPaymentTransactionObserver. Product is successfully being requested but transaction observer is never calling paymentQueue.
How can I make it work so I can detect Cancel button?

Answer 1

in delegate method i look at the tutorial failedtransaction does nothing if user cancels. but you can add it like that.
- (void)failedTransaction:(SKPaymentTransaction *)transaction
{
if (transaction.error.code != SKErrorPaymentCancelled)
{
// error!
NSLog(#"Something went Wrong!");
[self finishTransaction:transaction wasSuccessful:NO];
NSLog(#"transaction error :%#", transaction.error.localizedDescription);
}
else
{
NSLog(#"Cancelled");
// this is fine, the user just cancelled
[[SKPaymentQueue defaultQueue] finishTransaction:transaction];
}
}

Answer 2

This line had to be added to make it work:
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
Thanks all for your help.

Answer 3

I haven't used StoreKit, but I'm guessing that your SKRequestDelegate will receive the message request:didFailWithError: if the user cancels.