/// <summary>
        /// 加载AB包
        /// </summary>
        public IEnumerator LoadAssetBundle()
        {
            //使用www下载
            using (WWW www = new WWW(_abDownloadPath))
            {
                yield return(www);

                if (www.progress >= 1)
                {
                    AssetBundle ab = www.assetBundle;
                    if (ab != null)
                    {
                        //实例化下一级的引用
                        assetLoader = new AssetLoader_1(ab);

                        //调用委托
                        if (_loadCompleteHandle != null)
                        {
                            _loadCompleteHandle(_abName);
                        }

                        www.Dispose();
                    }
                    else
                    {
                        Debug.LogError("www下载AB包失败");
                    }
                }
            }
        }
 public SingleABLoader_2(string firstDirName, string abName, UnityAction <string> loadComplete)
 {
     assetLoader         = null;
     _firstDirName       = firstDirName;
     _abName             = abName;
     _abDownloadPath     = RuntimeABPath.GetWWWPath() + "/" + _firstDirName + "/" + abName;
     _loadCompleteHandle = loadComplete;
 }