微信小程序wx.downloadfile下载实现进度条

js:

 data: {
   add:'0',
  },

 daan:function(){ 
     const downloadTask = wx.downloadFile({
      url: 'https://6363-ccs-6g4z452b9e86fd77-1305582300.tcb.qcloud.la/gsdaan/gs2/gs2/%E9%AB%98%E7%AD%89%E6%95%B0%E5%AD%A6%E5%90%8C%E6%B5%8E%E7%AC%AC%E4%B8%83%E7%89%88%E4%B8%8B%E5%86%8C%E4%B9%A0%E9%A2%98%E5%85%A8%E8%A7%A3%E6%8C%87%E5%8D%97%20(1).pdf?sign=31962fd5102ac30d5a73eceeda62e2e2&t=1670580319',      //要预览的PDF的地址
      success: function (res) {
        if (res.statusCode === 200) {   //成功
          var Path = res.tempFilePath //返回的文件临时地址，用于后面打开本地预览所用
          wx.openDocument({
            filePath: Path, //要打开的文件路径
            success: function (res) {
              wx.hideLoading()
              console.log('打开PDF成功');
            }
          })
        }
      },
      fail: function (res) {
        wx.showToast({
          title: '加载失败',
        })
      }
    })

    //进度条
    downloadTask.onProgressUpdate((res)=>{ 
      if (res.progress === 100) {
         this.setData({
           add: '100'
         });
        return 
        } else {
          wx.showLoading({
            title: `正在进入...${res.progress}%`,
          })
          this.setData({
            add: res.progress
          });
        }
    })
  }

.wxml

<text class="title">正在进入：{{add}}%</text>