createWithSpriteFrameName nullptr

bool WelcomeLayer::init()
{
  bool bl = Layer::init();
  //缓存纹理 
  SpriteFrameCache::getInstance()->addSpriteFramesWithFile("gameArts-hd.plist"); 
  //加入背景
  Sprite *background = Sprite::createWithSpriteFrameName("background_2.png");
  this->addChild(background);
//  background->setAnchorPoint(Point(0, 0));
  return bl;
}

文件资源错误！