how to close layer that showed in other layer in cocos2d-iphone - cocos2d-iphone

Question

I have one layer called alayer, and there is a button called abutton, when click the button, another layer called blayer will show in alayer, not replaceScene, please look at the following code,
alayer.m
-(void)abuttonclicked:(id)sender
{
blayer *blayer = [blayer node];
blayer.position = ccp(1,1);
[self addChild:blayer];
}
blayer.m has a button called bbutton and string value called bstring, I want to click the b button, it will close blayer (remove blayer from alayer), and pass the string value bstring to alayer, please look at following code,
-(void)bbuttonclicked:(id)sender
{
// how can do here to close its self(remove its self from alayer), and pass the bstring to alayer?
}
thanks.
ps. I can use NSUserDefault to pass the string value, but I think it's a bad way to do this, is there another way to pass value?

Answer 1

maybe to pass the string you could declare and implement a property in ALayer.h/.m
#property(nonatomic,copy) NSString *stringFromLayerB;
to remove bLayer when bButtonClicked :
-(void)bbuttonclicked:(id)sender
{
ALayer *lay = (ALayer*) self.parent;
lay.stringFromLayerB = #"Whatever you want to set";
[self removeFromParentAndCleanup:YES];
}
There are other ways to do this. You could implement a callback mechanism , use notifications, some kind of delegate protocol binding BLayer and ALayer. All depends what your real (unsaid) requirements are.

Answer 2

Considering your scenario, I think its better to use NSNotificationCenter.
You can post notification from blayer when the button is tapped and add an observer in alayer to respond exactly how to want.
Add [[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receivedNotification:) name:#"BlayerNotification" object:nil]; in alayer's init and [[NSNotificationCenter defaultCenter] removeObserver:self]; in its dealloc.
Its selector like:
- (void)receivedNotification:(NSNotification *)notification {
NSString *string = (NSString *)notification.object;
NSLog (#"String received %#", string);
}
Now you can post notification from blayer when hte button is clicked:
-(void)bbuttonclicked:(id)sender {
[[NSNotificationCenter defaultCenter] postNotificationName:#"BlayerNotification" object:self];
[self removeFromParentAndCleanup:YES];
}