resCount resTotal为文件统计，resTotal需在init中赋值，赋值大小必须与pathList文件夹下文件总和相等，否则会加载不全。
pathList中的路径为相对Resources文件夹下的路径，所以为了方便起见，不建议在Resources下直接存放资源文件

头文件

#ifndef LoadingScene_hpp
#define LoadingScene_hpp

#include <stdio.h>
#include "cocos2d.h"
class LoadingScene : public cocos2d::Layer
{
private:
    unsigned int resCount;
    unsigned int resTotal;
    std::list<std::string> pathList;
public:
    static cocos2d::Scene* createScene();
    virtual bool init();
    std::list<std::string> getFilesFromPath(std::string path);
    void loadResources();
    void loadCallback(cocos2d::Ref* pSender);

    CREATE_FUNC(LoadingScene);
};

#endif /* LoadingScene_hpp */

源文件

#include "LoadingScene.hpp"
//以下是遍历文件所需头文件
#include <sys/stat.h>
#include "dirent.h"
#include "unistd.h"

USING_NS_CC;

Scene* LoadingScene::createScene()
{
    auto scene = Scene::create();
    auto layer = LoadingScene::create();
    scene->addChild(layer);
    return scene;
}
bool LoadingScene::init()
{
    resCount = 0;
    resTotal = 100;
    pathList.clear();
    pathList.push_back("images");
    pathList.push_back("images/images2");
    this->loadResources();
    return true;
}
std::list<std::string> LoadingScene::getFilesFromPath(std::string path)
{
    std::list<std::string> files;
    std::string filePath = FileUtils::getInstance()->fullPathForFilename(path);
    DIR *dp;
    struct dirent *entry;
    struct stat statbuf;
    dp=opendir(filePath.c_str());
    chdir(filePath.c_str());
    while((entry=readdir(dp))!=NULL)
    {
        stat(entry->d_name,&statbuf);
        if(!S_ISREG(statbuf.st_mode))
            continue;
        files.push_back(path+"/"+entry->d_name);
    }
    return files;
}
void LoadingScene::loadResources()
{
    CCLOG("start loading");
    while(pathList.size()>0)
    {
        std::list<std::string> files=getFilesFromPath(pathList.back());
        while(files.size()>0)
        {
            Director::getInstance()->getTextureCache()->addImageAsync(files.back(), CC_CALLBACK_1(LoadingScene::loadCallback, this));
            CCLOG("loading %s",files.back().c_str());
            files.pop_back();
        }
        pathList.pop_back();
    }
}
void LoadingScene::loadCallback(cocos2d::Ref *pSender)
{
    resCount++;
    if (resCount == resTotal)
    {
        //加载完成就切换场景
    }
}