有些授权是这样的，需要调用 openSetting 那个 api 来引导用户打开设置权限页面，一般配合 wx.showModal 使用

因为有些机型，特别是Android拒绝后就进入静默状态，不会再弹出

你可以试下这个代码：

/**
     * 获取用户保存相册权限
     */
    getPhotosAuthorize: function () {
      let self = this;
      wx.getSetting({
        success(res) {
          console.log(res)
          if (!res.authSetting['scope.writePhotosAlbum']) {
            wx.authorize({
              scope: 'scope.writePhotosAlbum',
              success() {
                console.log('授权成功')
                self.saveImg();
              },
              //用户拒绝
              fail() {
                //self.secondGetPhoteAuthor();
              }
            })
          } else {
            self.saveImg();
          }
        }
      })
    },
/**
     * 二次弹窗获取 相册权限
     */
    secondGetPhoteAuthor(){
      let self = this;
      wx.showModal({
        title: '保存海报',
        content: '需要你提供保存相册权限',
        success: function (res) {
          if (res.confirm) {
            wx.openSetting({
              success(settingdata) {
                console.log(settingdata)
                if (settingdata.authSetting['scope.writePhotosAlbum']) {
                  console.log('获取 相册 权限成功，给出再次点击图片保存到相册的提示。');
                  self.saveImg()
                } else {
                  wx.hideLoading();
                  util.showToast("保存失败");
                  console.log('获取 相册 权限失败，给出不给权限就无法正常使用的提示')
                }
              }
            })
          } else {
            wx.hideLoading();
            util.showToast("保存失败");
          }
        }
      });
    },