JavaScript 图片切换展示效果

http://www.cnblogs.com/cloudgamer/archive/2008/07/06/1236770.html
代码效果

代码下载
test.htm (7714)
说明
首先需要一个容器，设置它的overflow为hidden，position为relative；
容器里面还要一个滑动对象，设置它的position为absolute；
在initialize()函数里初始化一些属性。

在切换之前先执行Start()函数，进行相关设置，
主要是设置Index属性(索引)和_target属性(目标值)：

if(this.Index < 0){
    this.Index = this._count - 1;
} else if  (this.Index >= this._count){ this.Index = 0; }

this._target = -1 * this._parameter * this.Index;

接着就执行Move()函数开始移动了，原理通过设置滑动对象的top(或left)来做出移动的效果，
而减速的效果就需要执行GetStep()函数来获取步长：

var iStep = (iTarget - iNow) / this.Step;

用目标值减当前值再除以一个参数，得到步长，
这样取得的步长在当前值越接近目标值时会越来越小，也做成了减速的效果，
然后在top(或left)的设置中加上这个步长，并设置定时器继续Move()，直到到达目标值：

this._slider.style[style] = (iNow + iStep) + "px";
this._timer = setTimeout(function(){ oThis.Move(); }, this.Time);

下面例子里的容器结构：
Code

<div class="container" id="idTransformView">
  <ul class="slider" id="idSlider">
    <li><img src="http://shundebk.cn/temp/1.jpg"/></li>
    <li><img src="http://shundebk.cn/temp/2.jpg"/></li>
    <li><img src="http://shundebk.cn/temp/3.gif"/></li>
  </ul>
  <ul class="num" id="idNum">
    <li>1</li>
    <li>2</li>
    <li>3</li>
  </ul>
</div>

要美观的话需要css设置一下：

.container, .container *{margin:0; padding:0;}

.container{width:408px; height:168px; overflow:hidden;}

.slider{position:absolute;}
.slider li{ list-style:none;display:inline;}
.slider img{ width:408px; height:168px; display:block;}

.slider2{width:2000px;}
.slider2 li{float:left;}

.num{ position:absolute; right:5px; bottom:5px;}
.num li{
    float: left;
    color: #FF7300;
    text-align: center;
    line-height: 16px;
    width: 16px;
    height: 16px;
    font-family: Arial;
    font-size: 12px;
    cursor: pointer;
    overflow: hidden;
    margin: 3px 1px;
    border: 1px solid #FF7300;
    background-color: #fff;
}
.num li.on{
    color: #fff;
    line-height: 21px;
    width: 21px;
    height: 21px;
    font-size: 16px;
    margin: 0 1px;
    border: 0;
    background-color: #FF7300;
    font-weight: bold;
}

样式的设置跟程序也有一定关系，例如宽和高，这里就不说明了。

接着就可以实例化了：

var tv = new TransformView ("idTransformView", "idSlider", 168, 3, {
    onStart : function(){ Each(objs, function(o, i) { o.className = tv.Index == i ? "on" : ""; })  }//按钮样式
});

这里主要有4个参数，分别是容器对象、滑动对象、切换参数和切换数量。
当程序是上下切换时，切换参数切换的高度，当左右切换时，是切换的宽度。
切换数量就是有多少个切换对象了，例如上面的例子就是3个。
最后的参数是一些设置：
属性: 默认值//说明
Up: true,//是否向上(否则向左)
Step: 5,//滑动变化率
Time: 10,//滑动延时
Auto: true,//是否自动转换
Pause: 2000,//停顿时间(Auto为true时有效)
onStart: function(){},//开始转换时执行
onFinish: function(){}//完成转换时执行
例子里设置了onStart属性，作用是在切换开始时，设置按钮的样式

<style type="text/css">
.container, .container *{margin:0; padding:0;}
.container{width:408px; height:168px; overflow:hidden;}
.slider{position:absolute;}
.slider li{ list-style:none;display:inline;}
.slider img{ width:408px; height:168px; display:block;}
.slider2{width:2000px;}
.slider2 li{float:left;}
.num{ position:absolute; right:5px; bottom:5px;}
.num li{
float: left;
color: #FF7300;
text-align: center;
line-height: 16px;
width: 16px;
height: 16px;
font-family: Arial;
font-size: 12px;
cursor: pointer;
overflow: hidden;
margin: 3px 1px;
border: 1px solid #FF7300;
background-color: #fff;
}
.num li.on{
color: #fff;
line-height: 21px;
width: 21px;
height: 21px;
font-size: 16px;
margin: 0 1px;
border: 0;
background-color: #FF7300;
font-weight: bold;
}
</style>
<div class="container" id="idTransformView">
<ul class="slider" id="idSlider">
    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_1.jpg" />

    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_2.jpg" />
    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_3.gif" /> </li>
</ul>
<ul class="num" id="idNum">
    <li>1 </li>
    <li>2 </li>
    <li>3 </li>
</ul>

</div>
<font face="Verdana">alibaba的按钮有一个延迟的功能，应该加个定时器，但这个不是重点就省了吧。<br />
<br />
</font><font face="Verdana">扩展成能左右切换：</font><br />
<div class="container" id="idTransformView2">
<ul class="slider slider2" id="idSlider2">
    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_1.jpg" /> </li>
    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_2.jpg" /> </li>
    <li><img alt="" src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_3.gif" /> </li>

</ul>
<ul class="num" id="idNum2">
    <li>1 </li>
    <li>2 </li>
    <li>3 </li>
</ul>
</div>
<br />
<font face="Verdana">其他扩展功能：</font><br />
<br />

<div><input id="idStop" type="button" value=" 停止自动 " /> <input id="idStart" type="button" value=" 开始自动 " /> <br />
<br />
<input id="idPre" type="button" value=" <- 上一个 " /> <input id="idNext" type="button" value=" 下一个 - /> "> <br />
<br />
切换速度： <input id="idFast" type="button" value=" + 加 速 " /> <input id="idSlow" type="button" value=" - 减 速 " /> <br />
<br />
停顿时间： <input id="idAdd" type="button" value=" + 加时间 " /> <input id="idReduce" type="button" value=" - 减时间 " /> <br />

<br />
<input id="idReset" type="button" value=" Reset " /> </div>
<script type="text/javascript">
var $ = function (id) {
 return "string" == typeof id ? document.getElementById(id) : id;
};
var Class = {
  create: function() {
 return function() {
   this.initialize.apply(this, arguments);
 }
  }
}
Object.extend = function(destination, source) {
 for (var property in source) {
  destination[property] = source[property];
 }
 return destination;
}
var TransformView = Class.create();
TransformView.prototype = {
  //容器对象,滑动对象,切换参数,切换数量
  initialize: function(container, slider, parameter, count, options) {
 if(parameter <= 0 || count <= 0) return;
 var oContainer = $(container), oSlider = $(slider), oThis = this;
 this.Index = 0;//当前索引

 this._timer = null;//定时器
 this._slider = oSlider;//滑动对象
 this._parameter = parameter;//切换参数
 this._count = count || 0;//切换数量
 this._target = 0;//目标参数

 this.SetOptions(options);

 this.Up = !!this.options.Up;
 this.Step = Math.abs(this.options.Step);
 this.Time = Math.abs(this.options.Time);
 this.Auto = !!this.options.Auto;
 this.Pause = Math.abs(this.options.Pause);
 this.onStart = this.options.onStart;
 this.onFinish = this.options.onFinish;

 oContainer.style.overflow = "hidden";
 oContainer.style.position = "relative";

 oSlider.style.position = "absolute";
 oSlider.style.top = oSlider.style.left = 0;

 //无缝切换
 //oContainer.appendChild(oSlider.cloneNode(true));
  },
  //设置默认属性
  SetOptions: function(options) {
 this.options = {//默认值
  Up:   true,//是否向上(否则向左)
  Step:  5,//滑动变化率
  Time:  10,//滑动延时
  Auto:  true,//是否自动转换
  Pause:  2000,//停顿时间(Auto为true时有效)
  onStart: function(){},//开始转换时执行
  onFinish: function(){}//完成转换时执行
 };
 Object.extend(this.options, options || {});
  },
  //开始切换设置
  Start: function() {
 if(this.Index < 0){
  this.Index = this._count - 1;
 } else if (this.Index >= this._count){ this.Index = 0; }

 this._target = -1 * this._parameter * this.Index;
 this.onStart();
 this.Move();
  },
  //移动
  Move: function() {
 clearTimeout(this._timer);
 var oThis = this, style = this.Up ? "top" : "left", iNow = parseInt(this._slider.style[style]) || 0, iStep = this.GetStep(this._target, iNow);

 if (iStep != 0) {
  this._slider.style[style] = (iNow + iStep) + "px";
  this._timer = setTimeout(function(){ oThis.Move(); }, this.Time);
 } else {
  this._slider.style[style] = this._target + "px";
  this.onFinish();


  //if(this.Index > this._count){


  //this._slider.style[style] = "0px";


  //}



  if (this.Auto) { this._timer = setTimeout(function(){ oThis.Index++; oThis.Start(); }, this.Pause); }
 }
  },
  //获取步长
  GetStep: function(iTarget, iNow) {
 var iStep = (iTarget - iNow) / this.Step;
 if (iStep == 0) return 0;
 if (Math.abs(iStep) < 1) return (iStep > 0 ? 1 : -1);
 return iStep;
  },
  //停止
  Stop: function(iTarget, iNow) {
 clearTimeout(this._timer);
 this._slider.style[this.Up ? "top" : "left"] = this._target + "px";
  }
};
window.onload=function(){
 function Each(list, fun){
  for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); }
 };

 var objs = $("idNum").getElementsByTagName("li");

 var tv = new TransformView("idTransformView", "idSlider", 168, 3, {
  onStart : function(){ Each(objs, function(o, i){ o.className = tv.Index == i ? "on" : ""; }) }//按钮样式
 });

 tv.Start();

 Each(objs, function(o, i){
  o.onmouseover = function(){
   o.className = "on";
   tv.Auto = false;
   tv.Index = i;
   tv.Start();
  }
  o.onmouseout = function(){
   o.className = "";
   tv.Auto = true;
   tv.Start();
  }
 })

 ////////////////////////test2

 var objs2 = $("idNum2").getElementsByTagName("li");

 var tv2 = new TransformView("idTransformView2", "idSlider2", 408, 3, {
  onStart: function(){ Each(objs2, function(o, i){ o.className = tv2.Index == i ? "on" : ""; }) },//按钮样式
  Up: false
 });

 tv2.Start();

 Each(objs2, function(o, i){
  o.onmouseover = function(){
   o.className = "on";
   tv2.Auto = false;
   tv2.Index = i;
   tv2.Start();
  }
  o.onmouseout = function(){
   o.className = "";
   tv2.Auto = true;
   tv2.Start();
  }
 })

 $("idStop").onclick = function(){ tv2.Auto = false; tv2.Stop(); }
 $("idStart").onclick = function(){ tv2.Auto = true; tv2.Start(); }
 $("idNext").onclick = function(){ tv2.Index++; tv2.Start(); }
 $("idPre").onclick = function(){ tv2.Index--;tv2.Start(); }
 $("idFast").onclick = function(){ if(--tv2.Step <= 0){tv2.Step = 1;} }
 $("idSlow").onclick = function(){ if(++tv2.Step >= 10){tv2.Step = 10;} }
 $("idReduce").onclick = function(){ tv2.Pause-=1000; if(tv2.Pause <= 0){tv2.Pause = 0;} }
 $("idAdd").onclick = function(){ tv2.Pause+=1000; if(tv2.Pause >= 5000){tv2.Pause = 5000;} }

 $("idReset").onclick = function(){
  tv2.Step = Math.abs(tv2.options.Step);
  tv2.Time = Math.abs(tv2.options.Time);
  tv2.Auto = !!tv2.options.Auto;
  tv2.Pause = Math.abs(tv2.options.Pause);
 }

}
</script><br />

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2008-07-26_072727.gif
test.htm