unity3D shareSDK 回调不起作用

Question

ShareResultEvent evt = new ShareResultEvent(ShareResultHandler);
ShareSDK.showShareMenu (null, content, 100, 100, MenuArrowDirection.Up, evt);

void ShareResultHandler (ResponseState state, PlatformType type, Hashtable shareInfo, Hashtable error, bool end)
    {
        if (state == ResponseState.Success)
        {
            print ("share result :");
            print (MiniJSON.jsonEncode(shareInfo));
        }
        else if (state == ResponseState.Fail)
        {
            print ("fail! error code = " + error["error_code"] + "; error msg = " + error["error_msg"]);
        }
    }

分享成功后，回调从未工作