温馨提示：

errMsg: "openSetting:fail can only be invoked by user TAP gesture."

• wx.openSetting 不能直接在程序中调用，但是可以通过 wx.showModal 拉起。

小程序获取某项权限

• 【相关链接】微信小程序：开放能力/用户信息/授权
• 【相关链接】表单组件/button , open-type : openSetting
• uni -> wx ， 有些地方写的是 uni 直接替换为 wx
• 可以把 scope.userLocation 替换为其他值，或者封装一下，变成通用的获取权限方式
• 封装时，别忘记，把 "需要您授权获取地理位置权限" 也封装一下，这个是弹窗的提示信息
• 提示： 这里的几个方法 promise 返回的是数组，arr[0] 有值，就是出错了；arr[1]才是success时返回的结果值，想要获取的结果值都存放在 arr[1] 中。

// (1) uni.getSetting -> (2) uni.authorize -> (3) uni.showModal -> (4) uni.openSetting
//授权获取地理位置权限
async getAuth_userLocation(){
  try {
    //(1)getSetting
    const authSetting = await uni.getSetting();
    if (authSetting['scope.userLocation']) {
      return true;
    } else {
      //(2)authorize
      const resAuthorize = await uni.authorize({ scope: 'scope.userLocation' })
      //resAuthorize[0]:拒绝,resAuthorize[1]:接受;
      if (resAuthorize[1]) {
        return true;
      } else {
        //(3)showModal
        const resShowModal = await uni.showModal({ title: '授权', content: '需要您授权获取地理位置权限' });
        //resShowModal[0]: null, resShowModal[1]: `confirm`,`cancel`都定义在"resShowModal[1]"中
        if (resShowModal[1]) {
          if (resShowModal[1].confirm) {
            //(4)openSetting
            const resOpenSetting = await uni.openSetting();
            //resOpenSetting[0]: null, resOpenSetting[1]: `authSetting`定义在"resOpenSetting[1]"中
            if (resOpenSetting[1]) {
              const authSetting = resOpenSetting[1].authSetting;
              if (authSetting && authSetting['scope.userLocation']) {
                return true;
              } else {
                return false;
              }
            } else {
              return false;
            }
          }
          if (resShowModal[1].cancel) {
            return false;
          }
        } else {
          return false;
        }
      }
    }
  } catch (err) {
    console.log(err);
    return false;
  }
},

原来的写法

getCameraAuth(){
  const that = this;
  // 获取摄像头权限
  // (1) uni.getSetting -> (2) uni.authorize -> (3) uni.showModal -> (4) uni.openSetting
  uni.getSetting({
    success(res) {
      const authSetting = res.authSetting;
      if (authSetting['scope.camera']) {
        // 已经授权
        that.is_camera_auth = true;
      } else {
        // 未授权
        uni.authorize({
          scope: 'scope.camera',
          success(resSuccess) {
            // 同意授权
            that.is_camera_auth = true;
          },fail(resFail) {
            console.log("resFail: ", resFail);
            // 引导用户授权
            uni.showModal({
              title: '授权',
              content: '需要您授权获取摄像头权限',
              success: function (res) {
                if (res.confirm) {
                  uni.openSetting({
                    success(resOpenSetting) {
                      // resOpenSetting: {errMsg: "openSetting:ok", authSetting: {scope.camera: false}}
                      //console.log("resOpenSetting: ", resOpenSetting)
                      const authSetting = resOpenSetting.authSetting
                      if (authSetting && authSetting['scope.camera']) {
                        that.is_camera_auth = true;
                      } else {
                        uni.showToast({icon:'none', title: '您拒绝授权小程序获取摄像头权限', duration: 1500});
                      }
                    }
                  });
                } else if (res.cancel) {
                  uni.showToast({icon:'none', title: '您拒绝授权小程序获取摄像头权限', duration: 1500});
                }
              }
            });
          }
        });
      }
    }
  });
},

• 这是原来的嵌套写法，没有上面的 Promise 版本方便；放在这里作为参照。