// 文件预览
  pre_show: function (src, name, callback = false) {
    // console.log(src);
    // console.log(name);
    // console.log(callback);
    if (!(src && name)) {
      return false;
    }
    wx.showLoading({
      title: "下载中...",
      mask: true,
    });
    var fs = wx.getFileSystemManager();
    var df = wx.downloadFile({
      url: src,
      // filePath: `${wx.env.USER_DATA_PATH}/${name}`,
      success: function (params) {
        // console.log(params);
        if (params.statusCode === 200) {
          // 重新改写文件后缀
          fs.saveFile({
            tempFilePath: params.tempFilePath,
            // wx.env.USER_DATA_PATH 是微信提供了一个用户文件目录给开发者，开发者对这个目录有完全自由的读写权限
            filePath: `${wx.env.USER_DATA_PATH}/${name}`,
            success: function (params2) {
              // console.log(params2);
              // console.log(params2.savedFilePath) // params2.savedFilePath 为一个本地缓存文件路径
              if (callback != false) {
                callback(params2.savedFilePath);
                wx.hideLoading();
                df.offProgressUpdate();
                return false;
              }
              var src_arr = src.split(".");
              var ext = src_arr[src_arr.length - 1].toLowerCase();
              // console.log(ext);
              if (["doc", "docx", "xls", "xlsx", "ppt", "pptx", "pdf"].indexOf(ext) === -1) {
                // 预览图片
                wx.previewImage({
                  urls: [src],
                  complete: function (params4) {
                    // console.log(params4);
                    wx.hideLoading();
                    df.offProgressUpdate();
                  },
                });
              } else {
                // 预览文档
                wx.openDocument({
                  filePath: params2.savedFilePath,
                  showMenu: true,
                  complete: function (params4) {
                    // console.log(params4);
                    wx.hideLoading();
                    df.offProgressUpdate();
                  },
                });
              }

            },
          });
        }

      },
    });

    // df.onProgressUpdate(function (params) {
    //   // console.log(params);
    //   // wx.showLoading({
    //   //   title: "下载中..." + params.progress + "%",
    //   //   // title: JSON.stringify(params),
    //   //   mask: true,
    //   // });
    //   wx.showToast({
    //     title: JSON.stringify(params),
    //     mask: true,
    //     icon: "none",
    //   });
    // });

  },