@implementation Game
{
    SPButton *_button;
}

- (id)init
{
    if (self = [super init])
    {
        // create a button
        SPTexture *buttonTexture = [SPTexture textureWithContentsOfFile:@"button.png"];
        _button = [SPButton buttonWithUpState:buttonTexture];
        [self addChild:_button];
        
        // here's the interesting part:
        [_button addEventListener:@selector(onButtonTriggered:) atObject:self
                          forType:SP_EVENT_TYPE_TRIGGERED];
    }
    return self;
}

- (void)onButtonTriggered:(SPEvent *)event
{
    NSLog(@"The button was triggered!");
}