Swallow touches, unless touching a child of my current layer - iphone

Question

I am writing a pause menu using a CCLayer. I need the layer to swallow touches so that you cannot press the layer below, however I also need to be able to use the buttons on the pause layer itself.
I can get the layer to swallow touches, but the menu won't work either.
Here is my code:
pauseLayer.m
#import "PauseLayer.h"
#implementation PauseLayer
#synthesize delegate;
+ (id) layerWithColor:(ccColor4B)color delegate:(id)_delegate
{
return [[[self alloc] initWithColor:color delegate:_delegate] autorelease];
}
- (id) initWithColor:(ccColor4B)c delegate:(id)_delegate {
self = [super initWithColor:c];
if (self != nil) {
NSLog(#"Init");
self.isTouchEnabled = YES;
CGSize wins = [[CCDirector sharedDirector] winSize];
delegate = _delegate;
[self pauseDelegate];
CCSprite * background = [CCSprite spriteWithFile:#"pause_background.png"];
[self addChild:background];
CCMenuItemImage *resume = [CCMenuItemImage itemFromNormalImage:#"back_normal.png"
selectedImage:#"back_clicked.png"
target:self
selector:#selector(doResume:)];
resume.tag = 10;
CCMenu * menu = [CCMenu menuWithItems:resume,nil];
[menu setPosition:ccp(0,0)];
[resume setPosition:ccp([background boundingBox].size.width/2,[background boundingBox].size.height/2)];
[background addChild:menu];
[background setPosition:ccp(wins.width/2,wins.height/2)];
}
return self;
}
-(void)pauseDelegate
{
NSLog(#"pause delegate");
if([delegate respondsToSelector:#selector(pauseLayerDidPause)])
[delegate pauseLayerDidPause];
}
-(void)doResume: (id)sender
{
if([delegate respondsToSelector:#selector(pauseLayerDidUnpause)])
[delegate pauseLayerDidUnpause];
[self.parent removeChild:self cleanup:YES];
}
- (void)onEnter {
[[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:INT_MIN+1 swallowsTouches:YES];
[super onEnter];
}
- (void)onExit {
[[CCTouchDispatcher sharedDispatcher] removeDelegate:self];
[super onExit];
}
- (BOOL)ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
return YES;
}
-(void)dealloc
{
[super dealloc];
}
#end

Answer 1

why dont you just disable touches on the game layer?
like in the onEnter method disable the touches on the game layer..and onExit re enable them
something like
-onEnter{
gameLayer.isTouchEnabled=NO;
....
}
-onExit{
gameLater.isTouchEnabled=YES;
...
}
also you wont need CCTouchDispatcher

Answer 2

According to your code, the problem is the modal layer is swallowing events even if it's for the own children.
To solve this problem, you have to set the touch priority of the children even higher than the modal layer itself.
In other words, set the menu's touch priority value below modal layer's.
There are two solutions.
Simply override "CCMenu::registerWithTouchDispatcher()" method and set the priority higher from the beginning.
Change menu's touch priority using "setPriority" method of the touchDispatcher or "setHandlerPriority" of menu itself.
To achieve second solution, you have to pay attention to the timing.
"CCMenu::registerWithTouchDispatcher()" is called somewhere AFTER "onEnter" and "onEnterTransitionDidFinish".
So, use "scheduleOnce" or something like that.
Sample codes.
- (id) initWithColor:(ccColor4B)c delegate:(id)_delegate {
self = [super initWithColor:c];
if (self != nil) {
//your codes...... put CCMenu in instance
[self scheduleOnce:#selector(setMenuPriority:) delay:0];
}
return self;
}
- (void) setMenuPriority (ccTime)dt {
[[[CCDirector sharedDirector] touchDispatcher] setPriority:INT_MIN forDelegate:menu];
//priority "INT_MIN" because you set the layer's priority to "INT_MIN+1".
}
PS: My english is not so good, so if there are loose sentences, correction will be very pleased :)

Answer 3

The problem is, that the layer/node hierarchy is not considered when propagating touches.
The touches are handed from the touch handler with the smallest priority value to the ones with the highest.
The touches are not forwarded anymore, once one of the responders swallows the touch.
You can use an approach similar to CCMenu. CCMenu handles all touches and detects which CCMenuItemhas been selected, based on the position of these items.
If you implement this the same way, you let your PauseLayer handle and swallow all touches and use a seperate mechanism to determine which child element in your PauseLayer has been selected.
Example Implementation: CCMenu Subclass
I have implemented a solution in this repository:
https://github.com/Ben-G/MGWU-Widgets/tree/master/Projectfiles/Components/CCMenuBlocking
That component is a CCMenuSubclass that swallows all touches and does not forward them.
Example Implementation: CCNode
Here is a more general solution of a CCNode that swallows touches and only forwards them to its own children:
https://github.com/Ben-G/MGWU-Widgets/blob/master/Projectfiles/Components/Popup/PopUp.m