Question

I want to receive a message so that I can show a “Processing…” overlay while the app is communicating with the App Store to complete the In App Purchase. Is there a callback that will fire only once the user has entered their credentials so that I’m not showing the “Processing…” behind the UIAlertView?

Answer 1

Turns out there is a callback for exactly this, I just missed it. The SKPaymentTransactionObserver‘s method paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions will get called whenever the transaction state changes, including when it changes to SKPaymentTransactionStatePurchasing, so you can do something like this:

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions
{
    for (SKPaymentTransaction *transaction in transactions)
    {
    if (transaction.transactionState == SKPaymentTransactionStatePurchasing) {
        // do your stuff
    }
}