public void AsyncLoad(string url, AsyncLoadCallBack.CallBack onAsyncRequestCallBack, object context)
{
url = url + GetExtension( );
//UnityEngine.Debug.Log( string.Format( " ## {0}", url ) );
AssetBundleCache cab = _cacheMgr.GetAssetBundle(url);
if (cab == null)
{
CreateRequest(url, onAsyncRequestCallBack, context);
return;
}
// 缓存中已有AB数据，检查一下依赖项量是否完成（有可能正在加载）
string[] dependsObj = GetAbDependencies(url);
if (dependsObj == null)
{
// 没有依赖项，缓存中已有AB数据，直接回调
if (onAsyncRequestCallBack != null)
{
onAsyncRequestCallBack(context, cab.AB);
}
return;
}
// 遍历依赖项是否在缓存中
bool isOk = true;
foreach (var one in dependsObj)
{
if (_cacheMgr.GetAssetBundle(one) != null)
{
continue;
}
isOk = false;
break;
}
if (isOk)
{
// 缓存中有全部数据，直接回调
if (onAsyncRequestCallBack != null)
{
onAsyncRequestCallBack(context, cab.AB);
}
return;
}
// AB包不全，需要创建requset
CreateRequest(url, onAsyncRequestCallBack, context);
}
private void CreateRequest(string url, AsyncLoadCallBack.CallBack onAsyncRequestCallBack, object context)
{
// ①：先创建一个回调
AsyncLoadCallBack callbackFun = new AsyncLoadCallBack(onAsyncRequestCallBack, context);
// ③是否已有加载数据，已有，注册一个回调函数，等待返回
if (_requests.ContainsKey(url))
{
_requests[url].Callbacks.Add(callbackFun);
return;
}
// ②：没有加载相关数据，新建一个异步请求，注册一个回调函数
// url可能已存在于缓存，需要请求的是依赖项
AsyncLoadRequest request =
new AsyncLoadRequest(url, AssetBundleMgr.GetInstance( ).GetAbDependencies(url));
request.Callbacks.Add(callbackFun);
_requests.Add(url, request);
AssetBundle ab = GetAb(url);
if (ab == null)
{
RegisterLoadedCallBack(url, request.UrlLoadedCallBack);
}
else
{
// 主ab包已经加载了，需要加载的是依赖包
string depsUrl = request.GetUnLoadUrl( );
RegisterLoadedCallBack(depsUrl, request.UrlLoadedCallBack);
url = depsUrl;
}
// ④：没有正在下载的相同url，排个队
if (!IsLoading(url))
{
_waitingQueue.Enqueue(url);
}
}
