It seems, that method is called twice, when collision happens . cocos2d-iphone - cocos2d-iphone

Question

I use this code to show game over menu after _hero sprite and _enemy sprite collide :
if (CGRectIntersectsRect(_hero.boundingBox,_enemy.boundingBox)) {
CCActionCallFunc *_callShowMenu=[CCActionCallFunc actionWithTarget:self selector:#selector(showMenu)];
[self runAction:_callShowMenu];
// EDIT : I also remove both sprites when collision happens.
[_hero removeFromParent];
[_enemy removeFromParent];
}
In _callShowMenu I just stop all actions and show a sprite with half transparent black background image and buttons.
Sometimes when collision happens, it seems to me, that _callShowMenu is called twice, because
background is completely black, like there is the same image behind. Has anyone had a similar problem? (Mostly background image is half-transparent, as it should be).
EDIT:
-(void)showMenu{
[[CCDirector sharedDirector] pause];
CCSprite *_halfTransparentBackground=[CCSprite spriteWithImageNamed:#"halfTransparentBackground.png"];
_halfTransparentBackground.position=ccp(160, 280);
[self addChild:_blackBack z:5];
}

Answer 1

I found a solution using BOOL. Actually everyone uses BOOL in this case, so I don't need to reinvent the wheel.
BOOL doNotCallMeTwice;
Somewhere in the didLoad method:
doNotCallMeTwice=NO;
In the collision detection method:
if (doNotCallMeTwice==NO) {
[self showMenu];
}
And finally:
-(void)showMenu{
doNotCallMeTwice=YES;
}
Possibly, showMenu was called twice(or much more times),because collision detection is in the update method.