var that = this;
    wx.authorize({
      scope: 'scope.camera',
      success () {
        console.log('同意调取摄像头授权')
      }
    })


    wx.getSetting({
      success(res) {
        if (res.authSetting['scope.camera']) {
          console.log(' camera 已授权')
          wx.scanCode({
            onlyFromCamera:false,//相册或相机获取二维码
            success (res) {}
              else
            {
              console.log('camera 未授权')
                     }
// 现在申请权限拉不起来，无法打开摄像头扫码