微信小程序实现页面下拉刷新和上拉加载功能详解

let col1H = 0;
let col2H = 0;
Page({
 data: {
  scrollH: 0,
  imgWidth: 0,
  loadingCount: 0,
  images: [],
  col1: [],
  col2: []
 },
 onLoad: function () {
  wx.getSystemInfo({
   success: (res) => {
    let ww = res.windowWidth;
    let wh = res.windowHeight;
    let imgWidth = ww * 0.48;
    let scrollH = wh;
    this.setData({
     scrollH: scrollH,
     imgWidth: imgWidth
    });
    //加载首组图片
    this.loadImages();
   }
  })
 },
 PullDownRefresh:function(){
  console.log("页面下拉2");
 },
  onShow: function () {
   console.log("页面显示");
 },
 /**
  * 生命周期函数--监听页面隐藏
  */
 onHide: function () {
  console.log("页面隐藏");
 },
 /**
  * 用户点击右上角分享
  */
 onShareAppMessage: function () {
  console.log("点击分享");
 },
 onImageLoad: function (e) {
  let imageId = e.currentTarget.id;
  let oImgW = e.detail.width;     //图片原始宽度
  let oImgH = e.detail.height;    //图片原始高度
  let imgWidth = this.data.imgWidth; //图片设置的宽度
  let scale = imgWidth / oImgW;    //比例计算
  let imgHeight = oImgH * scale;   //自适应高度
  let images = this.data.images;
  let imageObj = null;
  for (let i = 0; i