/// isKeyboardEnabled setter
void CCLayer::setKeyboardEnabled(bool enabled)
{
    if (enabled != _keyboardEnabled)
    {
        _keyboardEnabled = enabled;

        CCDirector* pDirector = CCDirector::sharedDirector();
        if (enabled)
        {
            pDirector->getKeyboardDispatcher()->setKeyPressDelegate( CC_CALLBACK_1(CCLayer::keyPressed, this) );
            pDirector->getKeyboardDispatcher()->setKeyReleaseDelegate( CC_CALLBACK_1(CCLayer::keyReleased, this) );
        }
        else
        {
            pDirector->getKeyboardDispatcher()->setKeyPressDelegate(nullptr);
            pDirector->getKeyboardDispatcher()->setKeyReleaseDelegate(nullptr);
        }
    }
}