怎么样使用jQuery制作基础的Web图片轮播效果?
首先看一下效果:
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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