//开始异步加载AssetBundle类型的资源
//远程下载文件到内存中成为AssetBundle镜像，再开辟内存从AssetBundle镜像中创建出指定Asset，最后卸载掉AB镜像内存，只保留Asset对象
private static IEnumerator BeginAssetBundleLoadAsync(ResourceItem item)
{
var isMainifest = IsManifest(item.Path);
var path = AssetPathConfig.GetAssetPathWWW(!isMainifest ? item.Path.ToLower() : item.Path);
item.SetLoadState(EResItemLoadState.Loading);
//if (item.Path.Contains("atlas")) LoggerHelper.Error("begin atlas path: " + item.Path);
var www = new WWW(path);
yield return www;
if (string.IsNullOrEmpty(www.error))
{
item.SetLoadState(EResItemLoadState.Completed);
//Debug.LogError("load success, path: " + www.url);
if (!item.IsSaveAssetBundle || !IsSaveBundle(item.Path))
{
Object mainAsset = null;
var bundle = www.assetBundle;
if (isMainifest)
{
//LoggerHelper.Error("is mainifest: " + item.Path);
mainAsset = bundle.LoadAsset("AssetBundleManifest");
item.SetMainAsset(mainAsset);
}
else
{
mainAsset = bundle.mainAsset;
if (mainAsset == null)
{
var assets = bundle.LoadAllAssets();
if (assets == null || assets.Length == 0)
{
Debug.LogError("load no assets, path: " + item.Path);
yield break;
}
mainAsset = assets[0];
item.SetMainAsset(mainAsset);
item.SetAssets(assets);
}
}
item.LaunchCallBack();
if (bundle != null)
bundle.Unload(false);
www.Dispose();
}
else
{
item.SetAssetBundle(www.assetBundle);
//if (item.Path.StartsWith("atlas")) LoggerHelper.Error("after atlas path: " + item.Path);
item.LaunchCallBack();
www.Dispose();
}
}
else
{
item.SetLoadState(EResItemLoadState.Error);
Debug.LogError(string.Format("加载资源失败：{0}\n{1}", www.url, www.error));
item.LaunchCallBack();
}
//按需清除ResourceItem缓存
if (item.IsClearAfterLoaded)
{
Clear(item.Path);
GarbageCollect();
}
}