Weird bug in my Cocos2d Game

Question

I am done making a very simple Cocos2d educational game for kids. The game shows the user bubbles with letter or number and a voice tells the user to pop the particular letter or alphabet. The game works fine most of the time but sometimes the game says "Pop the Letter R". and then when you try to touch and pop it does not pop. This happens 10% of the time which is preventing me to submit the app to app store. I am not really sure where I am missing.

The method that selects random alphabets or numbers:

The options in the below code can be a NSMutableArray of which consists of alphabets from A to Z.

-(void) populateRandomBubbles:(NSMutableArray *) options 
{
    int randomNumber;
    int randomBubbleColor; 
    NSString *option = @"";

    for(int i=0;i<self.gamePlaySettings.noOfBubblesToDisplay;i++) 
    {
        randomNumber = arc4random() % options.count; 
        randomBubbleColor = arc4random() % self.bubbleColors.count; 
        option = [options objectAtIndex:randomNumber];

        CGPoint point = [self getRandomPointOnScreen]; 

        // add first bubble 
        Bubble *bubble = [[Bubble alloc] initWithColor:[self getRandomBubbleColor]];
        bubble.delegate = self; 
        bubble.text = option; 
        bubble.soundFile = [[option stringByAppendingPathExtension:@"caf"] lowercaseString];
        bubble.sprite.position = point; 

        bubble.tag = [option characterAtIndex:0];

        [bubble setStringForLabel:bubble.text];

        if([self getChildByTag:bubble.tag] == nil)
        {
            if(  (int) (self.bubbles.count) < self.gamePlaySettings.noOfBubblesToDisplay)
            {
                [self.bubbles addObject:bubble];
            }
        }
        else 
        {
            i--;
        }
    }

    // set the randomly selected alphabet 

    randomNumber = arc4random() % self.bubbles.count; 

    Bubble *bubble = [self.bubbles objectAtIndex:randomNumber];
    bubble.isSelected = YES;

    // play sound 
    [self.environment playSoundByFileName:bubble.soundFile];

}

The Bubble class is defined below:

@implementation Bubble

@synthesize soundFile,text,isSelected,color,label,delegate = _delegate;

-(id) initWithColor:(NSString *)bubbleFile
{
    self = [super init];
    self.sprite = [CCSprite spriteWithFile:bubbleFile];
    [self addChild:self.sprite];
    return self; 
}

-(void) pop
{

    CCParticleExplosion *explosion = [[CCParticleExplosion alloc] init];
    explosion.position = self.sprite.position;
    [explosion setAutoRemoveOnFinish:YES];
    [self.parent addChild:explosion];
    [self.parent removeChild:self cleanup:YES];

    Environment *environment = [[Environment alloc] init]; 
    [environment playPopSound];
}

- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {

    if([self containsTouchLocation:touch]) 
    {   
        // if this is the correct bubble then pop the bubble 

        if(self.isSelected) 
        {

            [self pop];
            [_delegate onBubblePop:self];

        }
        return YES;
    }

    return NO; 
}

The BaseNode is defined below:

@implementation BaseNode

@synthesize sprite;

-(void) onEnter
{
    [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES];
    [super onEnter];
}

-(void) onExit
{
    [[CCTouchDispatcher sharedDispatcher] removeDelegate:self];
    [super onExit];
}

- (CGRect)rect
{
    CGSize s = [self.sprite.texture contentSize];
    return CGRectMake(-s.width / 2, -s.height / 2, s.width, s.height);
}

- (BOOL)containsTouchLocation:(UITouch *)touch
{
    BOOL isCollided = CGRectContainsPoint([self.sprite boundingBox], [self convertTouchToNodeSpace:touch]);

    return isCollided; 

}

Any ideas where the bug is?

UPDATE 1:

The following code which is also pasted in the original makes sure that there are no duplicates. It seems to be working fine since I have never encountered any duplicate.

 if([self getChildByTag:bubble.tag] == nil)
        {
            if(  (int) (self.bubbles.count) < self.gamePlaySettings.noOfBubblesToDisplay)
            {
                [self.bubbles addObject:bubble];
            }
        }

Answer 1

I might have solved the problem. I think the problem was that I was never making a check to ensure that the objects in the bubbles collection are unique. The updated code is below:

NSArray *bubbleAlreadyInArray = [self.bubbles filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"tag == %d",bubble.tag]];


        if([self getChildByTag:bubble.tag] == nil)
        {
            if(  (int) (self.bubbles.count) < self.gamePlaySettings.noOfBubblesToDisplay)
            {
                // only add to the bubbles array if not already added!
                if(bubbleAlreadyInArray.count == 0)
                {
                [self.bubbles addObject:bubble];
                }
            }
        }
        else 
        {
            i--;
        }

I wonder if there is a better way than using NSPredicate but for now it works fine and does not get duplicates.

Answer 2

it's actually here...

[self.parent removeChild:self cleanup:YES];

needs to be

[self.parent removeChild:self.sprite cleanup:YES];

Answer 3

Try using this to ensure that you do not have any duplicates

int length = [YOURBUBBLEARRAY count];
NSMutableArray *indexes = [[NSMutableArray alloc] initWithCapacity:length];
for (int i=0; i<length; i++) [indexes addObject:[NSNumber numberWithInt:i]];
NSMutableArray *shuffle = [[NSMutableArray alloc] initWithCapacity:length];
while ([indexes count])
{
    int index = rand()%[indexes count];
    [shuffle addObject:[YOURBUBBLEARRAY objectAtIndex:index]];
    [indexes removeObjectAtIndex:index];
}
[indexes release];

Bubble *bubble = [shuffle objectAtIndex:randomNumber];

Hope that helps

Answer 4

The game works fine most of the time but sometimes the game says "Pop the Letter R".

The question is... are you popping the correct letter r? There's nothing in your code that avoids using duplicates. It's possible that there are two r's on the screen at the same time, and pressing one of them isn't triggering the action on the other.

Bubble *bubble = [self.bubbles objectAtIndex:randomNumber];

isn't setting both bubbles if there are duplicates.