IAP consumable triggers twice when buying once - iphone

Question

"not solved yet..."
I'm having an issue with my iap consumable packages. The thing is that when I buy one, it duplicates the purchase, making another one without requesting it. The alert View appears double also.
A curious thing: this errors only happens when I make an ipa of my app, and not when debugging it! I can't understand why...
Here is the productPurchase method implemented in my main menu where I put the IAP buttons:
- (void)productPurchased:(NSNotification *)notification {
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
NSString * productIdentifier = notification.object;
NSString* plistPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"XXXXX.plist"];
if(plistPath != nil){
int playerSilverCoins = [defaults integerForKey:#"userSilverCoins"];
int playerGoldCoins = [defaults integerForKey:#"userGoldenCoins"];
NSArray *coinsItems = [NSArray arrayWithContentsOfFile:plistPath];
for (NSDictionary *coinItem in coinsItems) {
if ([[coinItem objectForKey:#"productId"] isEqualToString:productIdentifier]) {
playerSilverCoins = playerSilverCoins + [[coinItem objectForKey:#"silverCoins"] integerValue];
playerGoldCoins = playerGoldCoins + [[coinItem objectForKey:#"goldenCoins"] integerValue];
[defaults setInteger:playerSilverCoins forKey:#"userSilverCoins"];
[defaults setInteger:playerGoldCoins forKey:#"userGoldenCoins"];
[defaults synchronize];
NSLog(#"product bought: %#" , productIdentifier);
NSString *message = nil;
if([[coinItem objectForKey:#"goldenCoins"] integerValue] == 0)
message = [NSString stringWithFormat:#"You have bought %d silver coins", [[coinItem objectForKey:#"silverCoins"] integerValue]];
else
message = [NSString stringWithFormat:#"You have bought %d golden coins and %d silver coins", [[coinItem objectForKey:#"goldenCoins"] integerValue],[[coinItem objectForKey:#"silverCoins"] integerValue]];
UIAlertView * alert = [[UIAlertView alloc]initWithTitle:#"XXXXX" message:message delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil, nil];
[alert show];
[alert release];
NSNumber* achievementContributor = [defaults objectForKey:#"AchievementContributor"];
if ([achievementContributor intValue] != 1 ) {
[[GameCenterAchievement sharedGameCenterAchievement] checkAchievements:_kContributor];
[defaults setObject:[NSNumber numberWithInt:1] forKey:#"AchievementContributor"];
[[GKAchievementHandler defaultHandler] notifyAchievementTitle:#"Contributor"
andMessage:#"Buy a coin pack"];
}
break;
}
}
}
}
I don't know if there's a problem there, or on my IAP classes where I implement the transactions, restore, etc. If someone needs more code, just ask for it. Thanks!

Answer 1

Make sure you are adding observer only ones.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(productPurchased:) name:IAPHelperProductPurchasedNotification object:nil];
Adding listener multiply times will cause a multiple calls of your callback method.
If you are reusing your class - remember to removeObserver after you dealloc it - it won't do it on it's own.