在web页面上图片切换（焦点图）效果实在是太常见了，PC端、移动端到处都有它的身影。
上次写了个tab选项卡的效果，在这里延续一下，改成图片切换的效果。
如果不需要自动播放，稍微修改下html标签、和css样式，tab选项卡JS里动画持续时间、去掉点击切换事件部分就可以了。
html
<div class="mslide" id="slide"> <ul class="mcontent"> <li><a href="#a1"><img src="images/01.jpg" /></a></li> <li><a href="#a2"><img src="images/02.jpg" /></a></li> <li><a href="#a3"><img src="images/03.jpg" /></a></li> <li><a href="#a4"><img src="images/04.jpg" /></a></li> </ul> <ul class="mhead"> <li>1</li> <li>2</li> <li>3</li> <li>4</li> </ul> </div><!-- End mslide -->
css
body,div,ul,li{margin:0;padding:0;} ul,li{list-style: none;} body{font-size: 100%; font-family: Helvetica,STHeiti,Droid Sans Fallback;} .mslide { position:relative; width:100%; overflow:hidden; margin: 15px 0; } .mcontent { width:100%; overflow:hidden; } .mcontent li { width:100%; float:left; } .mcontent li img { width:100%; } .mhead { position:absolute; bottom:5px; left:0; z-index: 10; text-align:center; width:100%; height:15px; line-height:15px; } .mhead li { display:inline-block; width:10px; height:10px; border:1px solid #999; border-radius:6px; margin:0 3px; overflow:hidden; font-size:0; line-height:0; vertical-align: top; background: transparent; color:rgba(0,0,0,0); } .mhead li.current { background:#F00; }
JS
/** * LBS mTabs (修改成图片切换) * =================================================== * opts.mtab tabs外围容器/滑动事件对象(一个CSS选择器) * opts.mhead tabs标题容器/点击对象(一个CSS选择器) * opts.mcontent tabs内容容器/滑动切换对象(一个CSS选择器) * opts.index tabs索引(默认0) 指定显示哪个索引的标题、内容 * opts.current tabs当前项的类名(默认current) * =================================================== **/ ;(function(){ window.mTabs = function(opts){ if(typeof opts === undefined) return; this.mtab = document.querySelector(opts.mtab); this.mhead = document.querySelector(opts.mhead); this.mcontent = document.querySelector(opts.mcontent); this.mheads = this.mhead.children; this.mcontents = this.mcontent.children; this.length = this.mheads.length; if(this.length < 1) return; if(opts.index > this.length-1) opts.index = this.length-1; this.index = this.oIndex = opts.index || 0; this.current = opts.current || 'current'; this.touch = {}; this.init(); } mTabs.prototype = { init: function(opts){ this.set(); this.initset(); this.bind(); }, initset: function(){ for(var i = 0; i < this.length; i++){ this.mheads[i].index = i; this.mheads[i].className = this.mheads[i].className.replace(this.current,''); this.mcontents[i].className = this.mcontents[i].className.replace(this.current,''); } this.mheads[this.index].className += ' '+this.current; this.mcontents[this.index].className += ' '+this.current; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; }, set: function(){ this.width = document.documentElement.clientWidth || document.body.clientWidth; this.mcontent.style.width = this.length * this.width + 'px'; for(var i = 0; i < this.length; i++) this.mcontents[i].style.width = this.width + 'px'; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; }, bind: function(){ var _this = this; this.mtab.addEventListener("touchstart",function(e){ _this.touchStart(e); }, false); this.mtab.addEventListener("touchmove",function(e){ _this.touchMove(e); }, false); this.mtab.addEventListener("touchend",function(e){ _this.touchEnd(e); }, false); this.mtab.addEventListener("touchcancel",function(e){ _this.touchEnd(e); }, false); this.mcontent.addEventListener('webkitTransitionEnd',function(){ _this.transitionEnd(); }, false); window.addEventListener("resize", function(){ setTimeout(function(){ _this.set(); },100); }, false); window.addEventListener("orientationchange",function(){ setTimeout(function(){ _this.set(); },100); }, false); }, touchStart: function(e){ this.touch.x = e.touches[0].pageX; this.touch.y = e.touches[0].pageY; this.touch.time = Date.now(); this.touch.disX = 0; this.touch.disY = 0; this.touch.fixed = ''; }, touchMove: function(e){ if(this.touch.fixed === 'up') return; e.stopPropagation(); if(e.touches.length > 1 || e.scale && e.scale !== 1) return; this.touch.disX = e.touches[0].pageX - this.touch.x; this.touch.disY = e.touches[0].pageY - this.touch.y; if(this.touch.fixed === ''){ if( Math.abs(this.touch.disY) > Math.abs(this.touch.disX) ){ this.touch.fixed = 'up'; }else{ this.touch.fixed = 'left'; } } if(this.touch.fixed === 'left'){ e.preventDefault(); if( (this.index === 0 && this.touch.disX > 0) || (this.index === this.length-1 && this.touch.disX < 0) ) this.touch.disX /= 4; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + ( this.touch.disX - this.index * this.width ) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + ( this.touch.disX - this.index * this.width ) + "px,0,0)"; } }, touchEnd: function(e){ if(this.touch.fixed === 'left'){ var _this = this, X = Math.abs(this.touch.disX); this.mcontent.style.webkitTransition = this.mcontent.style.transition = 'all 400ms'; if( (Date.now() - this.touch.time > 100 && X > 10) || X > this.width/2 ){ this.touch.time = Date.now(); this.touch.disX > 0 ? this.index-- : this.index++; this.index < 0 && (this.index = 0); this.index > this.length - 1 && (this.index = this.length - 1); if(this.index !== this.oIndex) this.replace(); } //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; } }, transitionEnd: function(){ this.mcontent.style.webkitTransition = this.mcontent.style.transition = 'all 0ms'; }, replace: function(){ this.mheads[this.index].className += ' '+this.current; this.mheads[this.oIndex].className = this.mheads[this.oIndex].className.replace(this.current,'').trim(); this.mcontents[this.index].className += ' '+this.current; this.mcontents[this.oIndex].className = this.mcontents[this.oIndex].className.replace(this.current,'').trim(); this.oIndex = this.index; } } }());
效果预览 (Chrome的移动模式、移动设备)
- 1
- 2
- 3
- 4
这个根据tab选项卡修改而成的图片切换能适应大部分web页面的需求。点击下载
现在来加上自动播放功能，在上面的html，css基础上做出一点修改，每次手动写入导航的指示的html标签太麻烦了，让程序来判断有几张图片，然后创建几个导航指示，这样html结构更简洁。
html
<div class="mslide" id="slideIMG"> <ul class="mcontent"> <li><a href="#a1"><img src="images/01.jpg" /></a></li> <li><a href="#a2"><img src="images/02.jpg" /></a></li> <li><a href="#a3"><img src="images/03.jpg" /></a></li> <li><a href="#a4"><img src="images/04.jpg" /></a></li> </ul> </div><!-- End mslide -->
css
body,div,ul,li{margin:0;padding:0;} ul,li{list-style: none;} body{font-size: 100%; font-family: Helvetica,STHeiti,Droid Sans Fallback;} .mslide { position:relative; width:100%; overflow:hidden; margin: 15px 0; } .mcontent { width:100%; overflow:hidden; } .mcontent li { width:100%; float:left; } .mcontent li img { width:100%; } .mhead { position:absolute; bottom:5px; left:0; z-index: 10; text-align:center; width:100%; height:15px; line-height:15px; } .mhead li { display:inline-block; width:10px; height:10px; border:1px solid #999; border-radius:6px; margin:0 3px; overflow:hidden; font-size:0; line-height:0; vertical-align: top; background: transparent; color:rgba(0,0,0,0); } .mhead li.current { background:#F00; }
JS代码和tab选项卡大部分相似，增加了自动播放、创建导航指示。
先贴JS出代码，供参考
/** * LBS mSlideIMG 顺序版-自动 * Date: 2014-5-11 * =================================================== * opts.mslide 外围容器/滑动事件对象(一个CSS选择器) * opts.mcontent 内容容器/滑动切换对象(一个CSS选择器) * opts.index 索引(默认0) 指定显示哪个索引的导航指示、图片项 * opts.navclass 导航容器的类名(默认mnav) * opts.current 当前项的类名(默认current) * opts.auto 是否自动播放 默认false * opts.delay 自动播放间隔时间 默认5秒 自动播放时有效 * opts.duration 动画持续时间 默认400ms * =================================================== **/ ;(function(){ window.mSlideIMG = function(opts){ if(typeof opts === undefined) return; this.mslide = document.querySelector(opts.mslide); this.mcontent = document.querySelector(opts.mcontent); this.mcontents = this.mcontent.children; this.mnav = null; this.mnavs = []; this.length = this.mcontents.length; if(this.length < 1) return; if(opts.index > this.length-1) opts.index = this.length-1; this.index = this.oIndex = opts.index || 0; this.current = opts.current || 'current'; this.navclass = opts.navclass || 'mnav'; this.duration = opts.duration || 400; this.auto = !!opts.auto || false; this.auto && (this.delay = opts.delay || 5); this.timer = null; this.touch = {}; this.init(); } mSlideIMG.prototype = { init: function(opts){ this.set(); this.initset(); this.bind(); }, initset: function(){ this.create(); for(var i = 0; i < this.length; i++){ if(getComputedStyle(this.mcontents[i],null).position === 'absolute') this.mcontents[i].style.position = 'relative'; if(getComputedStyle(this.mcontents[i],null).cssFloat !== 'left') this.mcontents[i].style.cssFloat = 'left'; } this.mnavs[this.index].className = this.current; this.mcontents[this.index].className += ' '+this.current; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; }, set: function(){ this.width = document.documentElement.clientWidth || document.body.clientWidth; this.mcontent.style.width = this.length * this.width + 'px'; for(var i = 0; i < this.length; i++) this.mcontents[i].style.width = this.width + 'px'; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; }, create: function(){ this.mnav = document.createElement('ul'), li = null, i = 0; for(; i < this.length; i++){ li = document.createElement('li'); li.innerHTML = i+1; this.mnavs.push(li); this.mnav.appendChild(li); } this.mnav.className = this.navclass; this.mslide.appendChild(this.mnav); }, bind: function(){ var _this = this; this.mslide.addEventListener("touchstart",function(e){ _this.touchStart(e); _this.auto && _this.stop(); }, false); this.mslide.addEventListener("touchmove",function(e){ _this.touchMove(e); _this.auto && _this.stop(); }, false); this.mslide.addEventListener("touchend",function(e){ _this.touchEnd(e); _this.auto && _this.start(); }, false); this.mslide.addEventListener("touchcancel",function(e){ _this.touchEnd(e); _this.auto && _this.start(); }, false); this.mcontent.addEventListener('webkitTransitionEnd',function(){ _this.transitionEnd(); }, false); window.addEventListener("resize", function(){ setTimeout(function(){ _this.set(); },100); }, false); window.addEventListener("orientationchange",function(){ setTimeout(function(){ _this.set(); },100); }, false); this.auto && this.start(); }, touchStart: function(e){ this.touch.x = e.touches[0].pageX; this.touch.y = e.touches[0].pageY; this.touch.time = Date.now(); this.touch.disX = 0; this.touch.disY = 0; this.touch.fixed = ''; }, touchMove: function(e){ if(this.touch.fixed === 'up') return; e.stopPropagation(); if(e.touches.length > 1 || e.scale && e.scale !== 1) return; this.touch.disX = e.touches[0].pageX - this.touch.x; this.touch.disY = e.touches[0].pageY - this.touch.y; if(this.touch.fixed === ''){ if( Math.abs(this.touch.disY) > Math.abs(this.touch.disX) ){ this.touch.fixed = 'up'; }else{ this.touch.fixed = 'left'; } } if(this.touch.fixed === 'left'){ e.preventDefault(); if( (this.index === 0 && this.touch.disX > 0) || (this.index === this.length-1 && this.touch.disX < 0) ) this.touch.disX /= 4; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + ( this.touch.disX - this.index * this.width ) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + ( this.touch.disX - this.index * this.width ) + "px,0,0)"; } }, touchEnd: function(e){ if(this.touch.fixed === 'left'){ var _this = this, X = Math.abs(this.touch.disX); if( (Date.now() - this.touch.time > 100 && X > 10) || X > this.width/2 ){ this.touch.time = Date.now(); this.touch.disX > 0 ? this.index-- : this.index++; this.index < 0 && (this.index = 0); this.index > this.length - 1 && (this.index = this.length - 1); if(this.index !== this.oIndex) this.replace(); } this.mcontent.style.webkitTransition = this.mcontent.style.transition = 'all '+ this.duration +'ms'; //this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translateX(" + (-this.index * this.width) + "px)"; this.mcontent.style.webkitTransform = this.mcontent.style.transform = "translate3d(" + (-this.index * this.width) + "px,0,0)"; } }, transitionEnd: function(){ this.mcontent.style.webkitTransition = this.mcontent.style.transition = 'all 0ms'; }, replace: function(){ this.mnavs[this.index].className = this.current; this.mnavs[this.oIndex].className = ''; this.mcontents[this.index].className += ' '+this.current; this.mcontents[this.oIndex].className = this.mcontents[this.oIndex].className.replace(this.current,'').trim(); this.oIndex = this.index; }, start : function(){ if(this.length < 2) return; var _this = this; this.timer = setInterval(function(){ _this.index++; _this.index > _this.length - 1 && (_this.index = 0); if(_this.index !== _this.oIndex) _this.replace(); _this.mcontent.style.webkitTransition = _this.mcontent.style.transition = 'all '+ _this.duration +'ms'; //_this.mcontent.style.webkitTransform = _this.mcontent.style.transform = "translateX(" + (-_this.index * _this.width) + "px)"; _this.mcontent.style.webkitTransform = _this.mcontent.style.transform = "translate3d(" + (-_this.index * _this.width) + "px,0,0)"; },this.delay*1000); }, stop : function(){ clearInterval(this.timer); this.timer = null; } } }());
导航指示根据有几张图片来创建 (滑动切换容器ul.mcontent -> 包裹图片li标签，这里就是判断有几个li标签)
this.mcontent = document.querySelector(opts.mcontent);
this.mcontents = this.mcontent.children;
//..
this.length = this.mcontents.length;
//..
create: function(){
this.mnav = document.createElement('ul'), li = null, i = 0;
for(; i < this.length; i++){
li = document.createElement('li');
li.innerHTML = i+1;
this.mnavs.push(li);
this.mnav.appendChild(li);
}
this.mnav.className = this.navclass;
this.mslide.appendChild(this.mnav);
}
自动播放是间隔一段时间改变一个索引值来实现的，这个索引值在开始的时候默认定义为0。每间隔一段时间，这个索引值增加1。
this.index = this.oIndex = opts.index || 0;
//..
start : function(){
//..
this.timer = setInterval(function(){
_this.index++;
_this.index > _this.length - 1 && (_this.index = 0);
//..
_this.mcontent.style.webkitTransition = _this.mcontent.style.transition = 'all '+ _this.duration +'ms';
_this.mcontent.style.webkitTransform = _this.mcontent.style.transform = "translate3d(" + (-_this.index * _this.width) + "px,0,0)";
},this.delay*1000);
}
有时候要清除自动播放，当用手指来切换图片时，要清除自动播放，手指离开时又开始自动播放。
stop : function(){
clearInterval(this.timer);//清除定时
this.timer = null;
}
//..
this.mslide.addEventListener("touchstart",function(e){
_this.touchStart(e);
_this.auto && _this.stop(); //手指移入 如果有自动播放则清除
}, false);
this.mslide.addEventListener("touchend",function(e){
_this.touchEnd(e);
_this.auto && _this.start(); //手指离开 重新开始自动播放
}, false);
有时同一个web页面，有好几个图片切换，希望有的能定时自动切换，有的不用定时，为程序增加一个接口设置是否自动播放，顺便把间隔时间，切换动画持续时间一起定义了。
this.auto = !!opts.auto || false; //默认没有自动播放 this.auto && (this.delay = opts.delay || 5); //默认间隔时间5秒 this.duration = opts.duration || 400; //默认动画持续时间400毫秒
自动播放的图片切换，差不多完成了，来看下效果 (Chrome的移动模式、移动设备)。
说一些要注意的地方，外围容器(这里是类名为mslide的div标签)要设置相对或者绝对定位、并溢出隐藏；图片容器(这里是li标签)要浮动，为了都显示在一排滚动的容器(这里是类名为mcontent的ul标签)要足够宽；新建的导航指示是相对于外围容器绝对定位的，注意层级问题(这些能在样式里面定义就在样式里定义，程序为了全面可以多做判断)。
这个图片切换当最后一项切换到第一项时，动画跨度大，方向也和前几次相反，有时需要更自然的切换，方向都一样，每次动画距离也一样，这是一种进价的图片切换(焦点图)，也叫无缝切换。说下思路：可以采用绝对定位方式(这个例子里的li标签绝对定位，在li标签上做动画切换) ，根据索引值，在切换前修正位置，切换完成后修正位置；可以采用复制节点方式(复制这个例子里的li标签、全部或者部分)，根据索引值判断修正位置(这个例子里动画切换的对象和要修正位置对象是mcontent)。
可以看下效果：
实际上根据业务需求，会做出不同的改变，比如图片要切换到那一项时才加载，图片切换在页面没有html标签(解析JSON数据生成标签)……不管它怎么变，只要掌握基本的原理，问题都能解决。