使用jQuery制作基础的Web图片轮播效果

Clarence 2016-04-22

首先看一下效果:

使用jQuery制作基础的Web图片轮播效果

就这么个意思,没截动图哈~

轮播效果分析:
轮播效果大致可以分为3个部分:轮播图片(图片或者是包含容器),控制轮播图显示的按钮(向左、向右按钮,索引按钮(例如上面效果图的顶部的数字按钮)),每隔一段时间轮流显示轮播图片。
轮播图的显示:要显示的轮播图显示,不需要显示的轮播图隐藏;通常将这些轮播图片以定位的方式重叠在一起,每次显示一张轮播图片。
控制按钮:鼠标点击或者移到索引按钮上面时,显示对应索引位置的轮播图;向上、向下按钮负责控制显示上一张、下一张轮播图片。
其它:一般索引按钮有激活状态和未激活状态共2种状态;鼠标移到轮播图片上面时应该停止自动轮播,鼠标离开时开始自动轮播。

轮播效果实现笔记:
jquery提供了丰富的选择器以及用来挑选元素的方法,这极大的简化了我们的开发,例如$(".slider-item").filter(".slider-item-selected")选择了当前处于激活状态的索引按钮。
两张轮播图的切换显示效果是通过jquery的fadeOut()和fadeIn()方法来实现的,具体的使用参照jquery的api;
CSS透明背景的实现:  background: rgba(0, 0, 0, 0.2);filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#33000000,endColorstr=#33000000); (可以参看下面的参看资料),兼容大部分主流浏览器包括IE;为什么不使用opacity呢?因为opacity会使文字也透明(子元素也会透明)。
HTML骨架很重要,你写的html的结果应该是良好的。

代码部分:

HTML:

<pre name="code" class="html"><div class="slider">

 <div class="slider-extra">
 <ul class="slider-nav">
  <li class="slider-item">1</li>
  <li class="slider-item">2</li>
  <li class="slider-item">3</li>
  <li class="slider-item">4</li>
 </ul>
 <div class="slider-page">
  <a class="slider-pre" href="javascript:;;"><</a>
  <a class="slider-next" href="javascript:;;">></a>
 </div>
 </div>
</div>

CSS:

* {
 padding: 0px;
 margin: 0px;
}
a {
 text-decoration: none;
}
ul {
 list-style: outside none none;
}
.slider, .slider-panel img, .slider-extra {
 width: 650px;
 height: 413px;
}
.slider {
 text-align: center;
 margin: 30px auto;
 position: relative;
}
.slider-panel, .slider-nav, .slider-pre, .slider-next {
 position: absolute;
 z-index: 8;
}
.slider-panel {
 position: absolute;
}
.slider-panel img {
 border: none;
}
.slider-extra {
 position: relative;
}
.slider-nav {
 margin-left: -51px;
 position: absolute;
 left: 50%;
 bottom: 4px;
}
.slider-nav li {
 background: #3e3e3e;
 border-radius: 50%;
 color: #fff;
 cursor: pointer;
 margin: 0 2px;
 overflow: hidden;
 text-align: center;
 display: inline-block;
 height: 18px;
 line-height: 18px;
 width: 18px;
}
.slider-nav .slider-item-selected {
 background: blue;
}
.slider-page a{
 background: rgba(0, 0, 0, 0.2);
 filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#33000000,endColorstr=#33000000);
 color: #fff;
 text-align: center;
 display: block;
 font-family: "simsun";
 font-size: 22px;
 width: 28px;
 height: 62px;
 line-height: 62px;
 margin-top: -31px;
 position: absolute;
 top: 50%;
}
.slider-page a:HOVER {
 background: rgba(0, 0, 0, 0.4);
 filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#66000000,endColorstr=#66000000);
}
.slider-next {
 left: 100%;
 margin-left: -28px;
}

JavaScript:

$(document).ready(function() {
 var length,
 currentIndex = 0,
 interval,
 hasStarted = false, //是否已经开始轮播
 t = 3000; //轮播时间间隔
 length = $('.slider-panel').length;
 
 //将除了第一张图片隐藏
 $('.slider-panel:not(:first)').hide();
 //将第一个slider-item设为激活状态
 $('.slider-item:first').addClass('slider-item-selected');
 //隐藏向前、向后翻按钮
 $('.slider-page').hide();
 
 //鼠标上悬时显示向前、向后翻按钮,停止滑动,鼠标离开时隐藏向前、向后翻按钮,开始滑动
 $('.slider-panel, .slider-pre, .slider-next').hover(function() {
 stop();
 $('.slider-page').show();
 }, function() {
 $('.slider-page').hide();
 start();
 });
 
 $('.slider-item').hover(function(e) {
 stop();
 var preIndex = $(".slider-item").filter(".slider-item-selected").index();
 currentIndex = $(this).index();
 play(preIndex, currentIndex);
 }, function() {
 start();
 });
 
 $('.slider-pre').unbind('click');
 $('.slider-pre').bind('click', function() {
 pre();
 });
 $('.slider-next').unbind('click');
 $('.slider-next').bind('click', function() {
 next();
 });
 
 /**
 * 向前翻页
 */
 function pre() {
 var preIndex = currentIndex;
 currentIndex = (--currentIndex + length) % length;
 play(preIndex, currentIndex);
 }
 /**
 * 向后翻页
 */
 function next() {
 var preIndex = currentIndex;
 currentIndex = ++currentIndex % length;
 play(preIndex, currentIndex);
 }
 /**
 * 从preIndex页翻到currentIndex页
 * preIndex 整数,翻页的起始页
 * currentIndex 整数,翻到的那页
 */
 function play(preIndex, currentIndex) {
 $('.slider-panel').eq(preIndex).fadeOut(500)
  .parent().children().eq(currentIndex).fadeIn(1000);
 $('.slider-item').removeClass('slider-item-selected');
 $('.slider-item').eq(currentIndex).addClass('slider-item-selected');
 }
 
 /**
 * 开始轮播
 */
 function start() {
 if(!hasStarted) {
  hasStarted = true;
  interval = setInterval(next, t);
 }
 }
 /**
 * 停止轮播
 */
 function stop() {
 clearInterval(interval);
 hasStarted = false;
 }
 
 //开始轮播
 start();
});

首先是初始化部分:将除了第一张轮播图片意外的图片都隐藏,并且隐藏向前、向后按钮,使第一个索引按钮处于激活状态。
事件部分:通过jquery的hover()绑定鼠标上悬以及离开时的事件处理, jquery的bind()方法绑定鼠标点击事件处理向前、向后翻动、
轮播控制:pre(), next(), play(), start()开始自动轮播,stop()停止自动轮播。
上面的js写的比较散,结构也不太好,读起来也比较费力,也不易使用,耦合度较高。下篇将给出一个纯粹的jquery轮播插件, 该插件可以定制各种效果,方便的配置以及可扩展。

下面是整体的代码:
index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>jquery轮播效果图 - by RiccioZhang</title>
<script type="text/javascript" src="scripts/jquery-1.9.1.js"></script>
<style type="text/css">
 * {
 padding: 0px;
 margin: 0px;
 }
 a {
 text-decoration: none;
 }
 ul {
 list-style: outside none none;
 }
 .slider, .slider-panel img, .slider-extra {
 width: 650px;
 height: 413px;
 }
 .slider {
 text-align: center;
 margin: 30px auto;
 position: relative;
 }
 .slider-panel, .slider-nav, .slider-pre, .slider-next {
 position: absolute;
 z-index: 8;
 }
 .slider-panel {
 position: absolute;
 }
 .slider-panel img {
 border: none;
 }
 .slider-extra {
 position: relative;
 }
 .slider-nav {
 margin-left: -51px;
 position: absolute;
 left: 50%;
 bottom: 4px;
 }
 .slider-nav li {
 background: #3e3e3e;
 border-radius: 50%;
 color: #fff;
 cursor: pointer;
 margin: 0 2px;
 overflow: hidden;
 text-align: center;
 display: inline-block;
 height: 18px;
 line-height: 18px;
 width: 18px;
 }
 .slider-nav .slider-item-selected {
 background: blue;
 }
 .slider-page a{
 background: rgba(0, 0, 0, 0.2);
 filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#33000000,endColorstr=#33000000);
 color: #fff;
 text-align: center;
 display: block;
 font-family: "simsun";
 font-size: 22px;
 width: 28px;
 height: 62px;
 line-height: 62px;
 margin-top: -31px;
 position: absolute;
 top: 50%;
 }
 .slider-page a:HOVER {
 background: rgba(0, 0, 0, 0.4);
 filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#66000000,endColorstr=#66000000);
 }
 .slider-next {
 left: 100%;
 margin-left: -28px;
 }
</style>
<script type="text/javascript">
 $(document).ready(function() {
 var length,
  currentIndex = 0,
  interval,
  hasStarted = false, //是否已经开始轮播
  t = 3000; //轮播时间间隔
 length = $('.slider-panel').length;
 
 //将除了第一张图片隐藏
 $('.slider-panel:not(:first)').hide();
 //将第一个slider-item设为激活状态
 $('.slider-item:first').addClass('slider-item-selected');
 //隐藏向前、向后翻按钮
 $('.slider-page').hide();
 
 //鼠标上悬时显示向前、向后翻按钮,停止滑动,鼠标离开时隐藏向前、向后翻按钮,开始滑动
 $('.slider-panel, .slider-pre, .slider-next').hover(function() {
  stop();
  $('.slider-page').show();
 }, function() {
  $('.slider-page').hide();
  start();
 });
 
 $('.slider-item').hover(function(e) {
  stop();
  var preIndex = $(".slider-item").filter(".slider-item-selected").index();
  currentIndex = $(this).index();
  play(preIndex, currentIndex);
 }, function() {
  start();
 });
 
 $('.slider-pre').unbind('click');
 $('.slider-pre').bind('click', function() {
  pre();
 });
 $('.slider-next').unbind('click');
 $('.slider-next').bind('click', function() {
  next();
 });
 
 /**
  * 向前翻页
  */
 function pre() {
  var preIndex = currentIndex;
  currentIndex = (--currentIndex + length) % length;
  play(preIndex, currentIndex);
 }
 /**
  * 向后翻页
  */
 function next() {
  var preIndex = currentIndex;
  currentIndex = ++currentIndex % length;
  play(preIndex, currentIndex);
 }
 /**
  * 从preIndex页翻到currentIndex页
  * preIndex 整数,翻页的起始页
  * currentIndex 整数,翻到的那页
  */
 function play(preIndex, currentIndex) {
  $('.slider-panel').eq(preIndex).fadeOut(500)
  .parent().children().eq(currentIndex).fadeIn(1000);
  $('.slider-item').removeClass('slider-item-selected');
  $('.slider-item').eq(currentIndex).addClass('slider-item-selected');
 }
 
 /**
  * 开始轮播
  */
 function start() {
  if(!hasStarted) {
  hasStarted = true;
  interval = setInterval(next, t);
  }
 }
 /**
  * 停止轮播
  */
 function stop() {
  clearInterval(interval);
  hasStarted = false;
 }
 
 //开始轮播
 start();
 });
</script>
</head>
<body>
 <div class="slider">
 <div class="slider-extra">
  <ul class="slider-nav">
  <li class="slider-item">1</li>
  <li class="slider-item">2</li>
  <li class="slider-item">3</li>
  <li class="slider-item">4</li>
  </ul>
  <div class="slider-page">
  <a class="slider-pre" href="javascript:;;"><</a>
  <a class="slider-next" href="javascript:;;">></a>
  </div>
 </div>
 </div>
</body>
</html>

至此一个简单的jquery轮播效果就完成了,当然还有很多需要改进的地方。

使用插件实现
上面的效果看起来还令人满意,唯一不足的就是:每次需要轮播效果时,要将代码复制粘贴过去,如果有些部分需要修改(例如:轮播时的动画效果,前一篇使用的是jquery的淡入淡出效果,如果改成滑动效果,不可避免的要修改js代码),那么就需要对js代码进行修改,对我所写的jquery轮播效果的js代码不熟悉的程序员来说,修改这些js确实很困难。轮播插件所要实现的目标之一就是插件可以灵活配置(不光只是本篇文章的插件),程序员只需要写少量的代码就可以实现丰富的功能,这当然是一件很好的事情。本篇文章的轮播插件的html和css部分需要程序员自己编写,而实现效果的js只需要少量的编写。
这里我们使用到的zslider插件在GitHub上开源:
github:https://github.com/ricciozhang/zslider_v1
嗯,我们来看代码:

(function($, window, document) { 
  //---- Statics 
  var DEFAULT_ANIMATE_TYPE = 'fade',  
    ARRAY_SLICE = [].slice, 
    ARRAY_CONCAT = [].concat 
    ; 
   
  //---- Methods 
  function concatArray() { 
    var deep = false, 
      result = []; 
    if(arguments.length > 0 &&  
        arguments[arguments.length - 1] === true) { 
      deep = true; 
    } 
    for(var i = 0; i < arguments.length; i++) { 
      if(!!arguments[i].length) { 
        if(deep) { 
          for(var j = 0; j < arguments[i].length; j++) { 
            //recursive call 
            result = ARRAY_CONCAT.call(result,  
                concatArray(arguments[i][j], true)); 
          } 
        } else { 
          result = ARRAY_CONCAT.call(result, arguments[i]); 
        } 
      } else if(i != arguments.length - 1 ||  
          (arguments[arguments.length - 1] !== true && 
              arguments[arguments.length - 1] !== false)) { 
        result.push(arguments[i]); 
      } 
    } 
    return result; 
  } 
 
  //----- Core 
  $.fn.extend({ 
    zslider: function(zsliderSetting, autoStart) { 
      var itemLenght = 0, 
        currItemIndex = 0, 
        started = false, 
        oInterval = {}, 
        setting = { 
          intervalTime: 3000, 
          step: 1, 
          imagePanels: $(), 
          animateConfig: { 
            atype: 'fade', 
            fadeInSpeed: 500, 
            fadeOutSpeed: 1000 
          }, 
          panelHoverStop: true, 
          ctrlItems: $(), 
          ctrlItemActivateType: 'hover' || 'click', 
          ctrlItemHoverCls: '', 
          flipBtn: {}, 
          panelHoverShowFlipBtn: true, 
          callbacks: { 
            animate: null 
          } 
        }, 
        that = this 
        ; 
       
      //core methods 
      var slider = { 
          pre: function() { 
            var toIndex = itemLenght +  
              (currItemIndex - setting.step) % itemLenght; 
            slider.to(toIndex); 
          }, 
          next: function() { 
            var toIndex = (currItemIndex + setting.step) % itemLenght; 
            slider.to(toIndex); 
          }, 
          to: function(toIndex) { 
            //handle the index value 
            if(typeof toIndex === 'function') { 
              toIndex = toIndex.call(that, concatArray(setting.imagePanels, true),  
                    concatArray(setting.ctrlItems, true), 
                      currItemIndex, step); 
            } 
            if(window.isNaN(toIndex)) { 
              toIndex = 0; 
            } 
            toIndex = Math.round(+toIndex) % itemLenght; 
            if(toIndex < 0) { 
              toIndex = itemLenght + toIndex; 
            } 
             
            var currentPanel = setting.imagePanels.eq(currItemIndex), 
            toPanel = setting.imagePanels.eq(toIndex), 
            currrntCtrlItem = setting.ctrlItems.eq(currItemIndex) 
            toCtrlItem = setting.ctrlItems.eq(toIndex) 
            ; 
            if(!setting.callbacks.animate ||  
                setting.callbacks.animate.call(that,  
                    concatArray(setting.imagePanels, true),  
                      concatArray(setting.ctrlItems, true), 
                        currItemIndex, toIndex) === true) { 
              currrntCtrlItem.removeClass(setting.ctrlItemHoverCls); 
              toCtrlItem.addClass(setting.ctrlItemHoverCls); 
               
              toPanel.fadeIn(setting.animateConfig.fadeInSpeed); 
              currentPanel.fadeOut(setting.animateConfig.fadeOutSpeed); 
            } 
             
            //set the current item index 
            currItemIndex = toIndex; 
          }, 
          start: function() { 
            if(!started) { 
              started = true; 
              oInterval =  
                window.setInterval(slider.next, setting.intervalTime); 
            } 
          }, 
          stop: function() { 
            if(started) { 
              started = false; 
              window.clearInterval(oInterval); 
            } 
          }, 
          isStarted: function() { 
            return started; 
          } 
      }; 
      function initData() { 
        if(zsliderSetting) { 
          var temp_callbacks = zsliderSetting.callbacks; 
           
          $.extend(setting, zsliderSetting); 
          $.extend(setting.callbacks, temp_callbacks); 
           
          itemLenght = setting.imagePanels.length; 
        } 
        //convert to the jquery object 
        setting.imagePanels = $(setting.imagePanels); 
        setting.ctrlItems = $(setting.ctrlItems); 
        setting.flipBtn.container = $(setting.flipBtn.container); 
        setting.flipBtn.preBtn = $(setting.flipBtn.preBtn); 
        setting.flipBtn.nextBtn = $(setting.flipBtn.nextBtn); 
      } 
      function initLook() { 
        //show the first image panel and hide other 
        setting.imagePanels.hide(); 
        setting.imagePanels.filter(':first').show(); 
        //activate the first control item and deactivate other 
        setting.ctrlItems.removeClass(setting.ctrlItemHoverCls); 
        setting.ctrlItems.filter(':first').addClass(setting.ctrlItemHoverCls); 
        $(that).css('overflow', 'hidden'); 
        if(setting.panelHoverShowFlipBtn) { 
          showFlipBtn(false); 
        } 
      } 
      function initEvent() { 
        $(concatArray(setting.imagePanels,  
            setting.flipBtn.preBtn, setting.flipBtn.nextBtn, true)).hover(function() { 
          if(setting.panelHoverStop) { 
            slider.stop(); 
          } 
          if(setting.panelHoverShowFlipBtn) { 
            showFlipBtn(true); 
          } 
        }, function() { 
          slider.start(); 
          if(setting.panelHoverShowFlipBtn) { 
            showFlipBtn(false); 
          } 
        }); 
        if(setting.ctrlItemActivateType === 'click') { 
          setting.ctrlItems.unbind('click'); 
          setting.ctrlItems.bind('click', function() { 
            slider.to($(this).index()); 
          }); 
        } else { 
          setting.ctrlItems.hover(function() { 
            slider.stop(); 
            slider.to($(this).index()); 
          }, function() { 
            slider.start(); 
          }); 
        } 
        setting.flipBtn.preBtn.unbind('click'); 
        setting.flipBtn.preBtn.bind('click', function() { 
          slider.pre(); 
        }); 
        setting.flipBtn.nextBtn.unbind('click'); 
        setting.flipBtn.nextBtn.bind('click', function() { 
          slider.next(); 
        }); 
      } 
      function init() { 
        initData(); 
         
        initLook(); 
         
        initEvent(); 
      } 
       
      function showFlipBtn(show) { 
        var hasContainer = setting.flipBtn.container.length > 0, 
          eles; 
        eles = hasContainer ? setting.flipBtn.container : 
          //to the dom array: 
          /*ARRAY_CONCAT.call(ARRAY_SLICE.apply(setting.flipBtn.preBtn), 
              ARRAY_SLICE.apply(setting.flipBtn.nextBtn));*/ 
          concatArray(setting.flipBtn.preBtn,  
                  setting.flipBtn.nextBtn, true); 
        if(show) { 
          $(eles).show(); 
        } else { 
          $(eles).hide(); 
        } 
      } 
       
      init(); 
      if(arguments.length < 2 || !!autoStart){ 
        slider.start(); 
      } 
      return slider; 
    } 
  }); 
})(jQuery, window, document);

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