CODEWITHSUNDEEP
iphonecrashcocos2d-iphoneremovechildtouch-event
Mazyod
Mazyod

Reputation: 22559

Cocos2D removeChildByTag crash?

Summary of the problem: After I launch the app, and press "New Game", I use CCDirector to transition to the GameScene. There, I add 32 GamePiece objects, where these objects handle touch events as follows:

@interface GamePiece : NSObject <CCTargetedTouchDelegate>{  

    CCSprite* sprite;

    NSInteger row;
    NSInteger column;

}

//-(void)moveToRow:(NSInteger)newRow column:(NSInteger)newColumn;
-(id)initWithRow:(NSInteger)aRow column:(NSInteger)aColumn tag:(NSInteger)tag parent:(CCNode*)parent;
+(id)gamePieceWithRow:(NSInteger)aRow column:(NSInteger)aColumn tag:(NSInteger)tag parent:(CCNode*)parent;

@end

GamePiece.m:

...
- (BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    CGPoint touchLocation = [GameScene locationFromTouch:touch];

    CCLOG(@"(%i, %i)", row, column); //<-----THIS!!!

    //Crash never makes it here....

    // Check if this touch is on the Spider's sprite.
    BOOL isTouchHandled = CGRectContainsPoint([sprite boundingBox], touchLocation);
    if (isTouchHandled){        
        id parent = sprite.parent;
        [parent gamePieceSelected:self inRow:row column:column];
    }

    return isTouchHandled;
}

...

- (void)dealloc {
    [[CCTouchDispatcher sharedDispatcher] removeDelegate:self]; //Important...
    [super dealloc];
}
@end

Ok, so After I load 32 pieces, I load even more pieces using the method:

[parent gamePieceSelected:self inRow:row column:column];

as follows: (GameScene.m)

-(void)gamePieceSelected:(GamePiece*)aGamePiece inRow:(NSInteger)row column:(NSInteger)column{
    [self removeChildByTag:18 cleanup:YES];
    //Array of index Path!!! row = row, section = column
    NSArray* moves = [self availableMovesForRow:row column:column];

    for(NSIndexPath* index in moves){ //Please forgive me for using NSIndexPath!! 
        [GamePiece gamePieceWithRow:[index row] column:[index section] tag:18 parent:self];
    }
}

So basically, when you tap a GamePiece, I add other GamePiece objects with tag = 18. I then use this tag to remove the "new" GamePiece objects, and add other ones..

My problem?

After taping a GamePiece, "new" game pieces appear appropriately, but it crashes after I tap more than once! I mean, I tap a GamePiece, the new gamePieces appears. Then, if I tap another GamePiece, I put my hand on my heart waiting for a crash.. Sometimes it crashes, other times it doesn't... The third time, fourth, fifth ... etc. I managed a highscore of 10 taps before it crashed :P ... so random....

My theory:

See the comment line //<------THIS, the CCLOG gets called an arbitrary number of times each time I tap the screen until it finds the GamePiece that satisfies the if statement, which is kinda normal, since I have many GamePiece objects loaded at the same time..

When it crashes (without any stack trace or messages), this CCLOG gets called a few times, and never makes it inside the if statement!! I think it is because it's trying to send a touch message to a GamePiece that has been removed by removeChildWithTag: .. But I already call [[CCTouchDispatcher sharedDispatcher] removeDelegate:self]; in dealloc, which leads to a very important fact:

If I wait a few seconds after taping a GamePiece before I tap another one, I have a higher chance of not crashing!!

It feels like I am giving it time to call dealloc, and remove the touch delegate...

EDIT: It occurred to me to add a CCLOG in dealloc, and it was never called... END EDIT

And am not sure if this is obvious, but if I DON'T remove the newly added GamePieces, the game never crashes... But I need to remove them :P

Please help, I have been fighting this issue for days >.

Upvotes: 2

Views: 633

Answers (1)

Mazyod
Mazyod

Reputation: 22559

THIS!!:

[[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:-1 swallowsTouches:YES]; //Important...

was the biggest mistake EVER!!

This neat piece of code:

[[CCTouchDispatcher sharedDispatcher] removeDelegate:self];

actually retains the delegate... and I never reach dealloc, and never removeDelegate from the touch dispatcher and cause a catastrophe ...

EDIT:

Ok, someone wants to know where I ended up removing the delegate! And I am surprised that I didn't mention that!

- (void)onExit {
    [[CCTouchDispatcher sharedDispatcher] removeDelegate:self];
    // Never forget this!!
    [super onExit];
}

Upvotes: 2

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