H5基于iScroll实现下拉刷新，上拉加载更多

前言

      前一段有个手机端的项目需要用到下拉刷新和上拉加载更多的效果，脑海里第一反映就是微博那种效果，刚开始的理解有些偏差，以为下拉也是追加数据，上拉也是追加数据，后请教同事后发现其实下拉只是刷新最新数据而已，上拉是追加数据。

 

使用技巧

      1、引用iScroll.js， 在初始化时添加两个事件监听：touchMove、DOMContentLoaded。

      2、实现iScroll插件的onScrollEnd事件， 也就是在这个事件里调用你自己的ajax方法实现数据的刷新和追加。

      3、上拉加载更多请求后台时就相当于分页请求数据，这时候需要在ajax请求时发送pageIndex参数，而初始化加载时需要从后台返回一个pageCount以便前台判断。

      4、最关键的就是实现下拉刷新方法(pullDownAction)和上拉加载更多(pullUpAction)方法。

 

效果图

 

实现方法

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var     myScroll,     pullDownEl, pullDownOffset,     pullUpEl, pullUpOffset,     generatedCount = 0;   /**  * 下拉刷新 （自定义实现此方法）  * myScroll.refresh(); 数据加载完成后，调用界面更新方法  */ function pullDownAction () {     setTimeout(function () {            var el, li, i;         el = document.getElementById('thelist');           for (i=0; i<3; i++) {             li = document.createElement('li');             li.innerText = 'Generated row ' + (++generatedCount);             el.insertBefore(li, el.childNodes[0]);         }                   myScroll.refresh();     //数据加载完成后，调用界面更新方法      }, 1000);   }   /**  * 滚动翻页 （自定义实现此方法）  * myScroll.refresh();      // 数据加载完成后，调用界面更新方法  */ function pullUpAction () {     setTimeout(function () {    // <-- Simulate network congestion, remove setTimeout from production!         var el, li, i;         el = document.getElementById('thelist');           for (i=0; i<3; i++) {             li = document.createElement('li');             li.innerText = 'Generated row ' + (++generatedCount);             el.appendChild(li, el.childNodes[0]);         }                   myScroll.refresh();     //数据加载完成后，调用界面更新方法     }, 1000);   }   /**  * 初始化iScroll控件  */ function loaded() {     pullDownEl = document.getElementById('pullDown');     pullDownOffset = pullDownEl.offsetHeight;     pullUpEl = document.getElementById('pullUp');       pullUpOffset = pullUpEl.offsetHeight;           myScroll = new iScroll('wrapper', {         scrollbarClass: 'myScrollbar',         useTransition: false,         topOffset: pullDownOffset,         onRefresh: function () {             if (pullDownEl.className.match('loading')) {                 pullDownEl.className = '';                 pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新...';             } else if (pullUpEl.className.match('loading')) {                 pullUpEl.className = '';                 pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载更多...';             }         },         onScrollMove: function () {             if (this.y > 5 && !pullDownEl.className.match('flip')) {                 pullDownEl.className = 'flip';                 pullDownEl.querySelector('.pullDownLabel').innerHTML = '松手开始更新...';                 this.minScrollY = 0;             } else if (this.y < 5 && pullDownEl.className.match('flip')) {                 pullDownEl.className = '';                 pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新...';                 this.minScrollY = -pullDownOffset;             } else if (this.y < (this.maxScrollY - 5) && !pullUpEl.className.match('flip')) {                 pullUpEl.className = 'flip';                 pullUpEl.querySelector('.pullUpLabel').innerHTML = '松手开始更新...';                 this.maxScrollY = this.maxScrollY;             } else if (this.y > (this.maxScrollY + 5) && pullUpEl.className.match('flip')) {                 pullUpEl.className = '';                 pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载更多...';                 this.maxScrollY = pullUpOffset;             }         },         onScrollEnd: function () {             if (pullDownEl.className.match('flip')) {                 pullDownEl.className = 'loading';                 pullDownEl.querySelector('.pullDownLabel').innerHTML = '加载中...';                                pullDownAction();   // ajax call             } else if (pullUpEl.className.match('flip')) {                 pullUpEl.className = 'loading';                 pullUpEl.querySelector('.pullUpLabel').innerHTML = '加载中...';                                pullUpAction(); // ajax call             }         }     });           setTimeout(function () { document.getElementById('wrapper').style.left = '0'; }, 800); }   //初始化绑定iScroll控件 document.addEventListener('touchmove', function (e) { e.preventDefault(); }, false); document.addEventListener('DOMContentLoaded', loaded, false);