微信小程序图片懒加载

原文链接： https://blog.csdn.net/zjy_android_blog/article/details/82726859

 

wxml: 

wxss:

/* pages/test/test.wxss */
.loadImg{
  width:100vw;
  height:46.3vw;
  transition: all .2s ease-in-out;
  opacity: 0;
}
.loadImg.active{
  opacity: 1
}

wxjs:

// pages/test/test.js
Page({
  data: {
    group: [
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/c67d9521db939fc8beb9a27b046ef1a3.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180914/02e62ee6cb44213c51976d00e4d21ab2.png",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      },
      {
        src: "https://csdnimg.cn/feed/20180913/8770caaf4959d5be0e6891c9f57efade.jpg",
        show: false,
        def: "https://img.alicdn.com/tps/i3/T1QYOyXqRaXXaY1rfd-32-32.gif"
      }
    ]
  },
  onLoad: function () {
    let group = this.data.group  // 获取原数据
    for (let i in group) {
      // 设置监听回调事件，当元素 .loadImg{{i}},进入页面20px内就触发回调事件，设置图片为真正的图片，通过show控制
      wx.createIntersectionObserver().relativeToViewport({ bottom: 20 }).observe('.loadImg' + i, (ret) => {
        if (ret.intersectionRatio > 0) {
          group[i].show = true
        }
        this.setData({ // 更新数据
          group
        })
      })
    }

  }
})

此文为转载，原作者博客：https://blog.csdn.net/zjy_android_blog/article/details/82726859