IWXAPI api = WXAPIFactory.createWXAPI(mContext, appId,false);
//        初始化 WXEmojiObject
            WXFileObject fileObj = new WXFileObject();
            fileObj.setContentLengthLimit(imagedata.length);

//            20720536
//            20720508
//            20718183
            Log.d(TAG, "length: "+imagedata.length);
            fileObj.fileData = imagedata;
            fileObj.filePath = path;

            WXMediaMessage msg = new WXMediaMessage(fileObj);
//            msg.mediaObject = fileObj;
            msg.title = title;
//            msg.description = description;
            //构造一个Req
            SendMessageToWX.Req req = new SendMessageToWX.Req();
            req.transaction = "file" + System.currentTimeMillis();

            req.message = msg;
            req.scene = SendMessageToWX.Req.WXSceneSession;
            api.sendReq(req);