微信小程序 详解页面跳转与返回并回传数据

<view class="flex-wrp">
    <text style="width: 32%;">选择城市</text>
    <input style="width: 68%;" type="text" bindtap="city" placeholder="请选择城市" value="{{cityname}}"/>
   </view>

page({
 data: {
  cityname:"深圳"  #用来回传的关键字，默认深圳
 },
 city: function(e){
  wx.navigateto({
    url: '../city/city'
  })
 }

})

citynameclick: function (event) {
  var cityname = event.currenttarget.dataset.cityname;
  console.log(cityname);

  var pages = getcurrentpages();
  var currpage = pages[pages.length - 1];  //当前页面
  var prevpage = pages[pages.length - 2]; //上一个页面

  //直接调用上一个页面的setdata()方法，把数据存到上一个页面中去
  prevpage.setdata({
   cityname: cityname
  })

  wx.navigateback();
 },