2022微信小程序开发中怎样做出城市选择

var city = require('../../utils/city.js');
var app = getApp()
Page({
 data: {
 searchLetter: [],
 showLetter: "",
 winHeight: 0,
 // tHeight: 0,
 // bHeight: 0,
 cityList: [],
 isShowLetter: false,
 scrollTop: 0,//置顶高度
 scrollTopId: '',//置顶id
 city: "上海市",
 hotcityList: [{ cityCode: 110000, city: '北京市' }, { cityCode: 310000, city: '上海市' }, { cityCode: 440100, city: '广州市' }, { cityCode: 440300, city: '深圳市' }, { cityCode: 330100, city: '杭州市' }, { cityCode: 320100, city: '南京市' }, { cityCode: 420100, city: '武汉市' }, { cityCode: 410100, city: '郑州市' }, { cityCode: 120000, city: '天津市' }, { cityCode: 610100, city: '西安市' }, { cityCode: 510100, city: '成都市' }, { cityCode: 500000, city: '重庆市' }]
 },
 onLoad: function () {
 // 生命周期函数--监听页面加载
 var searchLetter = city.searchLetter;
 var cityList = city.cityList();
 var sysInfo = wx.getSystemInfoSync();
 var winHeight = sysInfo.windowHeight;
 var itemH = winHeight / searchLetter.length;
 var tempObj = [];
 for (var i = 0; i < searchLetter.length; i++) {
  var temp = {};
  temp.name = searchLetter[i];
  temp.tHeight = i * itemH;
  temp.bHeight = (i + 1) * itemH;
  tempObj.push(temp)
 }
 this.setData({
  winHeight: winHeight,
  itemH: itemH,
  searchLetter: tempObj,
  cityList: cityList
 })
 },
 onReady: function () {
 // 生命周期函数--监听页面初次渲染完成
 },
 onShow: function () {
 // 生命周期函数--监听页面显示
 },
 onHide: function () {
 // 生命周期函数--监听页面隐藏
 },
 onUnload: function () {
 // 生命周期函数--监听页面卸载
 },
 onPullDownRefresh: function () {
 // 页面相关事件处理函数--监听用户下拉动作
 },
 onReachBottom: function () {
 // 页面上拉触底事件的处理函数
 },
 clickLetter: function (e) {
 console.log(e.currentTarget.dataset.letter)
 var showLetter = e.currentTarget.dataset.letter;
 this.setData({
  showLetter: showLetter,
  isShowLetter: true,
  scrollTopId: showLetter,
 })
 var that = this;
 setTimeout(function () {
  that.setData({
  isShowLetter: false
  })
 }, 1000)
 },
 //选择城市
 bindCity: function (e) {
 console.log("bindCity")
 this.setData({ city: e.currentTarget.dataset.city })
 },
 //选择热门城市
 bindHotCity: function (e) {
 console.log("bindHotCity")
 this.setData({
  city: e.currentTarget.dataset.city
 })
 },
 //点击热门城市回到顶部
 hotCity: function () {
 this.setData({
  scrollTop: 0,
 })
 }
})