jQuery如何实现上拉刷新功能

发布时间：2020-07-29 10:26:58 来源：亿速云阅读：222 作者：小猪栏目：web开发

这篇文章主要讲解了jQuery如何实现上拉刷新功能，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。

技术要点：

1、jQuery的插件写法

2、上拉刷新步骤分解

3、css样式

jQuery的插件写法：

$.fn.pluginName = function() {
  return this.each(function () {
    fn();
  })
};

上拉刷新步骤分解：

上拉刷新可以分解成三个部分：一是开始（start），记录当前鼠标的位置；二是移动（move），根据下拉的位移响应不同的视图；三是结束（end），刷新页面。

;!function ($) {
  "use strict";
  var PTR = function (ele) {
    this.container = $(ele);
    this.container.addClass('pull-to-refresh');
    this.distance = 60; // 设置参考的下拉位移
    this.attachEvent();
  };
  // 判断是否有touch事件发生
  var isTouch = (function () {
    var isSupportTouch = !!'ontouchstart' in document || window.documentTouch;
    return isSupportTouch;
  })();
  var touchEvents = {
    start: isTouch &#63; 'touchstart': 'mousedown',
    move: isTouch &#63; 'touchmove':'mousemove',
    end: isTouch &#63; 'touchend': 'mouseup'
  };
  // 获取事件发生时相对于文档的距离（含滚动距离）
  function getTouchPosition(e) {
     var e = e.orinalEvent || e;
     console.log(e)
     if(e.type === 'touchstart' || e.type === 'touchmove' || e.type === 'touchend') {
       return {
         x: e.targetTouches[0].pageX,
         y: e.targetTouches[0].pageY
       }
     }else {
       return {
         x: e.pageX,
         y: e.pageY
       }
     }
  };
  PTR.prototype.touchStart = function (e) {
    var p = getTouchPosition(e);
    this.start = p;
    this.diffX = this.diffY = 0;
  };
  PTR.prototype.touchMove = function (e) {
    if(this.container.hasClass('refreshing')) return;
    if(!this.start) return false;
    var p = getTouchPosition(e);
    this.diffX = p.x - this.start.x;
    this.diffY = p.y - this.start.y;
    if(this.diffY < 0) return;
    this.container.addClass('touching');
    e.preventDefault();
    e.stopPropagation();
    // 设置container的位移小于页面滚动的距离，给人一种用力下拉的错觉，提升用户体验
    this.diffY = Math.pow(this.diffY, .8);
    this.container.css('transform', 'translate3d(0,'+ this.diffY +'px, 0)');
    if(this.diffY < this.distance) {
      this.container.removeClass('pull-up').addClass('pull-down')
    }else {
      this.container.removeClass('pull-down').addClass('pull-up')
    }
  };
  PTR.prototype.touchEnd = function (e) {
    var _this = this;
    this.start = false;
    this.container.removeClass('pull-down');
    this.container.removeClass('pull-up');
    this.container.removeClass('touching');
    this.container.css('transform','');
    if(this.diffY >= this.distance) {
      this.container.addClass('refreshing');
      this.container.trigger('pull-to-refresh')
    }
  };
  // 事件处理程序，通过$.proxy(fn, content)绑定执行函数的上下文。
  PTR.prototype.attachEvent = function () {
    var ele = this.container;
    ele.on(touchEvents.start, $.proxy(this.touchStart, this));
    ele.on(touchEvents.move, $.proxy(this.touchMove, this));
    ele.on(touchEvents.end, $.proxy(this.touchEnd, this));
  };
  // 实例化构造函数
  var pullToRefresh = function (ele) {
    new PTR(ele)
  };
  var pullToRefreshDone = function (ele) {
    $(ele).removeClass('refreshing');
  };
  // jQuery 插件编写的一般模式
  $.fn.pullToRefresh = function () {
    // return 是插件可链式调用
    // this 在这里是一个jQuery对象，相当于$(ele)。因为在即时执行函数作用域中，没必要用“$(this)”的方式来把this包裹到一个jQuery对象中，因为this本身已经是被包装好的jQuery对象。
    // this.each()使插件代码为多元素集合中的每个元素单独起作用
    return this.each(function () {
      pullToRefresh(this);
    })
  };
  $.fn.pullToRefreshDone = function () {
    return this.each(function () {
      pullToRefreshDone(this);
    })
  }

}(window.jQuery);

HTML代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <link rel="stylesheet" href="pull-to-refresh.css" rel="external nofollow" >
  <style>
    p {
      margin-top: 0;
    }
  </style>
</head>
<body>
<div class="pull-to-refresh_layer">
  <div class="pull-to-refresh-arrow">↓</div>
  <div class="pull-to-refresh-preloader"></div>
  <div class="down">下拉刷新</div>
  <div class="up">释放刷新</div>
  <div class="refresh">正在刷新</div>
</div>
<div>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus amet aperiam, architecto at aut
    beatae dignissimos eaque est ex fugi
    at incidunt inventore natus nemo nostru
    m omnis quos repellat ut voluptas!
  </p>

</div>
<script src="../jquery-1.8.3.min.js"></script>
<script src="pull-to-refresh.js"></script>
<script>
  $(function () {
    $(document.body).pullToRefresh().on('pull-to-refresh', function () {
      setTimeout(function () {
        $(document.body).pullToRefreshDone();
      }, 2000)
    });
  })
</script>
</body>
</html>

CSS代码如下：

.pull-to-refresh {
  margin-top: -50px;
  transition: transform .4s;
}
.pull-to-refresh .pull-to-refresh-preloader,
.pull-to-refresh .up,
.pull-to-refresh .refresh {
  display: none;
}
.pull-to-refresh.refreshing {
  transform: translate3d(0,50px,0);
}

.refreshing .pull-to-refresh-arrow,
.refreshing .down,
.refreshing .up {
  display: none;
}
.refreshing .refresh,
.refreshing .pull-to-refresh-preloader {
  display: inline-block;
}
.pull-to-refresh_layer {
  height: 30px;
  line-height: 30px;
  padding-bottom: 10px;
}
.pull-down .pull-to-refresh_layer .up,
.pull-down .pull-to-refresh_layer .refresh {
  display: none;
}
.pull-down .pull-to-refresh_layer .down{
  display: inline-block;
}
.pull-up .pull-to-refresh_layer .up{
  display: inline-block;
}

.pull-up .pull-to-refresh_layer .down,
.pull-up .pull-to-refresh_layer .refresh {
  display: none;
}

.pull-up .pull-to-refresh-arrow {
  transform: rotate(180deg) translate3d(0, 0, 0);
}
.pull-to-refresh-arrow {
  display: inline-block;
  z-index: 10;
  margin-right: 4px;
  transition-duration: 300ms;
  transform: rotate(0deg) translate3d(0, 0, 0);
}

.pull-to-refresh_layer {
  display: inline-block;
}
.pull-to-refresh-preloader {
  display: inline-block;
}
.pull-down {

}
.pull-up {

}
.down {
  display: inline-block;
}
.up {
  display: inline-block;
}
.refresh {
  display: inline-block;
}

看完上述内容，是不是对jQuery如何实现上拉刷新功能有进一步的了解，如果还想学习更多内容，欢迎关注亿速云行业资讯频道。

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