微信小程序实现页面下拉刷新和上拉加载功能详解

本文实例讲述了微信小程序实现页面下拉刷新和上拉加载功能。分享给大家供大家参考，具体如下：

web手机端或app中经常会有下拉刷新，上拉加载这些功能。

微信小程序中如何实现下拉刷新，上拉加载的功能。

实现思路：

1.监听界面的下拉刷新事件和上拉加载事件

• bindscrolltolower 监听上拉加载
• bindscrolltoupper 监听下拉刷新

2.下拉刷新时清空数据列表，并重新请求数据进行界面展示。

3.上拉加载增量请求数据，增量增加数据列表，增量界面展示

效果图：

实现代码：

waterfall.wxml:

<!--pages/waterfall/waterfall.wxml-->
<view style="display:none">
 <image wx:for="{{images}}" wx:key="id" id="{{item.id}}" src="{{item.pic}}" bindload="onimageload"></image>
</view>
<scroll-view scroll-y="true" style="height:{{scrollh}}px" bindscrolltolower="loadimages" bindscrolltoupper="pulldownrefresh">
 <view style="width:100%">
  <view class="img_item">
   <view wx:for="{{col1}}" wx:key="id">
    <image src="{{item.pic}}" style="width:100%;height:{{item.height}}px"></image>
   </view>
  </view>
  <view class="img_item">
   <view wx:for="{{col2}}" wx:key="id">
    <image src="{{item.pic}}" style="width:100%;height:{{item.height}}px"></image>
   </view>
  </view>
 </view>
</scroll-view>

waterfall.js：

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 < images.length; i++) {
   let img = images[i];
   if (img.id === imageid) {
    imageobj = img;
    break;
   }
  }
  imageobj.height = imgheight;
  let loadingcount = this.data.loadingcount - 1;
  let col1 = this.data.col1;
  let col2 = this.data.col2;
  //判断当前图片添加到左列还是右列
  if (col1h <= col2h) {
   col1h += imgheight;
   col1.push(imageobj);
  } else {
   col2h += imgheight;
   col2.push(imageobj);
  }
  let data = {
   loadingcount: loadingcount,
   col1: col1,
   col2: col2
  };
  //当前这组图片已加载完毕，则清空图片临时加载区域的内容
  if (!loadingcount) {
   data.images = [];
  }
  this.setdata(data);
 },
 loadimages: function () {
  let images = [
   { pic: "../../images/1.png", height: 0 },
   { pic: "../../images/2.png", height: 0 },
   { pic: "../../images/3.png", height: 0 },
   { pic: "../../images/4.png", height: 0 },
   { pic: "../../images/5.png", height: 0 },
   { pic: "../../images/6.png", height: 0 },
   { pic: "../../images/7.png", height: 0 },
   { pic: "../../images/8.png", height: 0 },
   { pic: "../../images/9.png", height: 0 },
   { pic: "../../images/10.png", height: 0 },
   { pic: "../../images/11.png", height: 0 },
   { pic: "../../images/12.png", height: 0 },
   { pic: "../../images/13.png", height: 0 },
   { pic: "../../images/14.png", height: 0 }
  ];
  console.log("dasddasd" + images);
  let baseid = "img-" + (+new date());
  for (let i = 0; i < images.length; i++) {
   images[i].id = baseid + "-" + i;
  }
  this.setdata({
   loadingcount: images.length,
   images: images
  });
 }
})

希望本文所述对大家微信小程序设计有所帮助。