不能改变背景的颜色我有这个简单的类:这是C++文件:#include"HelloWorldScene.h"USING_NS_CC;HelloWorld::HelloWorld(){;}Scene*HelloWorld::createScene(){//'scene'isanautoreleaseobjectautoscene=Scene::create();//'layer'isanautoreleaseobjectautolayer=HelloWorld::create();//addlayerasachildtoscenescene->addChild(layer);//retur