Yesterday I was toying around with incorporating an iAd banner to my Cocos2D game. It was quite a struggle since the two didn’t play nicely together.

The first issue was that Cocos2D’s CCGLView – which is the director’s primary view – doesn’t support auto layout. Initially I used a scene to manage iAd’s ADBannerView – whenever an advertisement is ready then the scene will add the banner view as a subview of the director’s view and place some constraints to it. However the game crashed just after the constraints were added:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Auto Layout still required after executing -layoutSubviews. CCGLView's implementation of -layoutSubviews needs to call super.'

Upon closer inspection, apparently [CCGLView layoutSubview] doesn’t call [UIView layoutSubview] and that what caused the crash. I could modify CCGLView to add this call and perhaps submit a patch to the Cocos2D team – but then it’ll take quite some time to get it incorporated to the main distribution, if the patch got approved at all (and that’s a big “if”).

Facing this then I tried adding the banner view to the director’s parent view. However this failed with a “ADBannerView must be part of a view hierarchy managed by a UIViewController”. Then I was stuck again.

Fortunately after googling around I found a way to send a message to the superclass’ superclass (i.e. the grandparent class) by making use of an Objective-C runtime function. Then it’s quite straightforward to make a subclass of CCGLView that supports autolayout:

//
//  BSGLView.h
//  AirKill
//
//  Created by Sasmito Adibowo on 07-06-14.
//  Basil Salad Software, http://basilsalad.com
//
//  This code is in the public domain.

#import "CCGLView.h"

@interface BSGLView : CCGLView

@end

//
//  BSGLView.m
//  AirKill
//
//  Created by Sasmito Adibowo on 07-06-14.
//  Basil Salad Software, http://basilsalad.com
//
//  This code is in the public domain.
//

#import <objc/message.h>
#import "BSGLView.h"

@implementation BSGLView


-(void)layoutSubviews
{
    // We need this because CCGLView doesn't call UIView layoutSubviews and we need to add subviews
    
    Class granny = [[self superclass] superclass];
    struct objc_super theSuper = {self, granny};
    objc_msgSendSuper(&theSuper,_cmd);
    
    [super layoutSubviews];
}

@end

I then added used this class instead for CCDirector’s view and it now works nicely hosting a banner view on top of the game.

PS: you can use this gist instead to download the code above instead of taking the trouble to copy-paste it from this post.

That’s all for now. until next time!