Cocos2d layer and touches priority management - cocos2d-iphone

Question

I have my main scene, above it i set a new layer with CCLayer ,this layer has a button.
but when i hit that button (CCMenu), the layer behind it is also get the touches and do stuff.
I want to enable ONLY the upper layer touches, not the one under it .
How can i do that ? (setting touch priority ? how ? )
edit:
my layer is like that :
-(CCLayer*)showHelpLayer
{
self.isTouchEnabled=YES;
[[CCDirector sharedDirector].touchDispatcher addTargetedDelegate:self priority:-256 swallowsTouches:YES];
...
...
[self addChild:menu];
[menu setHandlerPriority:-257];
return self;
}
and i am adding it to the main scene like that :
helpLayer *hlp=[[helpLayer alloc]init];
[hlp showHelpLayer];
[self addChild:hlp z:100];

Answer 1

you could toy with priorities, but it gets nasty. I only do that in very very specific, well contained circumstances. The best approach is to disable input on your "underneath scene(s)" before you push the new layer and control objects.
If you chose to play with priorities, remember that all menus default to this priority (cocos2D 2.xx) :
kCCMenuHandlerPriority = -128,
so if you play with priority, i would put the layer at -256 (swallowing touches) and setHandlerPriority to -257 for your menu. So anything that falls through your menu is caught by the layer and swallowed (ie not passed 'below').
example for priority approach. The fly-through menu is a class that extends CCNode and does this onEnter, after creating all menu objects in the init method :
- (void)onEnter {
[super onEnter];
MPLOGDEBUG(#"");
[[CCDirector sharedDirector].touchDispatcher addTargetedDelegate:self priority:-256 swallowsTouches:YES];
[_backMenu setHandlerPriority:-257];
[_toggleOptionsMenu setHandlerPriority:-257];
[_dialogMenu setHandlerPriority:-257];
[_labelMenu setHandlerPriority:-257];
}