文件分享后，界面显示为0B，重要代码如下：

  /**
     * 分享文件
     */
    private void shareFile(ShareContent shareContent, int shareType) {
        WXFileObject fileObj = new WXFileObject();
        fileObj.setFilePath(shareContent.getFilePath());
        fileObj.setContentLengthLimit(1024*1024*10);
        Log.i("tobyy","==============bbbbb==="+shareContent.getFilePath());
//        fileObj.fileData = Util.inputStreamToByte(shareContent.getFilePath());//文件路径
//        fileObj.filePath =shareContent.getFilePath();
        WXMediaMessage msg = new WXMediaMessage(fileObj);
        msg.mediaObject=fileObj;
        msg.title = "title";
        msg.description="描述";
        SendMessageToWX.Req req = new SendMessageToWX.Req();
        req.transaction = buildTransaction("file");
        req.message = msg;
        req.scene =  shareType;
        mWXApi.sendReq(req);
    }