首先得写一个登录验证的界面  具体可参考以下链接
https://blog.csdn.net/weidong_y/article/details/79636386
然后在app.json中写上

  onLaunch: function() {    // 展示本地存储能力    var logs = wx.getStorageSync('logs') || []    logs.unshift(Date.now())    wx.setStorageSync('logs', logs)    const that = this    // 登录    wx.login({      success: res = {        const code= res.code        // 发送 res.code 到后台换取 openId, sessionKey, unionId`        wx.getSetting({          success: res = {            if (res.authSetting['scope.userInfo']) {              // 已经授权，可以直接调用 getUserInfo 获取头像昵称，不会弹框              wx.getUserInfo({                success: res = {                  // 可以将 res 发送给后台解码出 unionId                  console.log(res)                  this.globalData.userInfo = res.userInfo                  console.log(this.globalData.urls)                  wx.request({                    url: this.globalData.urls + "/api/login/get_openid",                    method: "POST",                    header: {                      "content-type": "application/x-www-form-urlencoded",                      'content-type': 'application/json' // 默认值                    },                    data: {                      code: code,                      nickname: this.globalData.userInfo.nickName,                      gender: this.globalData.userInfo.gender,                      avatarUrl: this.globalData.userInfo.avatarUrl                    },                    success: res = {                      console.log(res)                      //  that.globalData.openid = res.data.openid                      console.log(this.globalData.userInfo.nickName)                    }                  })                  // 由于 getUserInfo 是网络请求，可能会在 Page.onLoad 之后才返回                  // 所以此处加入 callback 以防止这种情况                  if (this.userInfoReadyCallback) {                    this.userInfoReadyCallback(res)                  }                }              })            }          }        })            }    })      },

注意 箭头函数的使用 因为如果不用箭头函数里面的this指向能把你绕崩了 使用箭头函数的好处是箭头函数没有自己的this 只能继承它外面那一层的this指向

想要实现登录验证  一般情况下 打开小程序时默认的页面为首页 如果没有验证过 则跳到验证页面 在验证页面点击允许后在跳回首页  验证的方法是在登录页面的onLoade函数中设置getstroge 在验证页面设置 setstorge