cocos2dx 4.0升级后，图片不显示

Cocos2d-x
#1

引擎从3.0升级到4.0后，脚本里tImage = ccui.ImageView:create()创建的控件，加载下载到本地的一张未加密的图片，怎么就显示不出来了，升级前是可以显示的，下面的代码有什么问题吗？
static void setImageViewNoEncrypt(Node* node, std::string path)
{
cocos2d::ui::ImageView * tImg = dynamic_cast<cocos2d::ui::ImageView *>(node);
if (tImg)
{
std::string _filePath = FileUtils::getInstance()->fullPathForFilename(path);
Data data = FileUtils::getInstance()->getDataFromFile(_filePath);

		if (!data.isNull())
		{
			cocos2d::Image * image = new Image();
			bool isOK = image->initWithImageData(data.getBytes(), data.getSize());
			if (isOK)
			{
				Texture2D* tRet = new Texture2D();
				bool isImage = tRet->initWithImage(image);
				if (isImage)
				{
					Sprite* imageRenderer = static_cast<Sprite*>(tImg->getVirtualRenderer());
					imageRenderer->setTexture(tRet);

					Rect rect = Rect::ZERO;
					rect.size = tRet->getContentSize();
					imageRenderer->setTextureRect(rect);
					CCSize tSize = imageRenderer->getContentSize();

					tImg->updateSizeAndPosition();
				}
				CC_SAFE_RELEASE(tRet);
			}

			CC_SAFE_RELEASE(image);

		}

	}
#2

用这个方法获取数据：
ssize_t readlen
unsigned char * buffer = NULL;
buffer = data .takeBuffer(&readlen)

std::string _filePath = FileUtils::getInstance()->fullPathForFilename(path);
Data data = FileUtils::getInstance()->getDataFromFile(_filePath);
修改成
Data data = FileUtils::getInstance()->getDataFromFile(path);