本文是自己仿写的小米轮播图的写法，通过透明度改变进行轮播的，新手，写的可能不是很好，有啥不合理的情况，望提出，指正，全部的代码放最下面
有很多写法重复，有空的时候，我把重复的代码封装一下
关于透明度渐变的动画效果
比如 delayOpacity(OliArray[pre],0,-0.1); 就是将OliArray[pre]这个对象的透明度转换成0，速度为0.1
function delayOpacity(obj,target,speed){
clearInterval(timer);
timer = setInterval(function(){
var old = getComputedStyle(obj,null)['opacity'];
var newVal = +old + +speed;//+是将字符串转变成number类型
if(parseInt(speed)>0 && newVal>=target){
newVal = 1;
}
if(parseInt(speed)<0 && newVal<=target){
newVal = 0;
}
obj.style.opacity = newVal;//每次将新的值赋值给该对象的透明度，产生渐变效果
if(newVal==target){
clearInterval(timer);//当透明度的值和目标中的透明度的值一样的时候，将定时器关闭
}
},100);
}关于自动轮播的方法
我的轮播有四张，但是写了五张图片，第五张和第一张图片是一样的，目的是为了透明度转换的比较合理，不会突然从最后一张变到第一张
全局变量 next代表轮播图将要切换的那一张，pre代表轮播图目前的这张
function autoPlay(){
autoTimer = setInterval(function(){
next++;
pre++;
next %= OliArray.length;
pre %= OliArray.length;
if(pre==OliArray.length-1){
pre = 0;
}
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = ""; //这个是点击时，除点击的那个原点外，其他的激活的样式清空
}
}
OliArray[next].style.zIndex=1;
delayOpacity(OliArray[pre],0,-0.1);//将上一张的透明度由1变成0
delayOpacity(OliArray[next],1,0.1);//将要显示的图片的透明度由0变成1
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;//到最后一张图片的时候，立即切换到第一张，相对于假装轮播到第一张了，因为用户的眼睛没有那么亮
}
PointerArray[next].className = "active";
},3000);
}关于点击上一张图片
prevBanner.onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
pre = next;//此时的pre就是原来切换到的那张图片
next = next-1>=0? next-1:OliArray.length-2;//next就是上一张,要切换的图片
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = "";
}
}
OliArray[next].style.zIndex = 1;
delayOpacity(OliArray[pre],0,-0.1);
delayOpacity(OliArray[next],1,0.1);
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;
}
PointerArray[next].className = "active";
pre = next - 1;
//开启自动轮播
autoPlay();
}关于点击下一张
和自动轮播有点像，但是没有定时器（这里我觉得可以封装函数来写，以后改一下）
nextBanner.onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
next++;
pre++;
next %= OliArray.length;
pre %= OliArray.length;
if(pre==OliArray.length-1){
pre = 0;
}
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = "";
}
}
OliArray[next].style.zIndex = 1;
delayOpacity(OliArray[pre],0,-0.1);
delayOpacity(OliArray[next],1,0.1);
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;
}
PointerArray[next].className = "active";
//开启自动轮播
autoPlay();
}关于点击某个原点，切换到该原点的图片
for(let i=0;i<PointerArray.length;i++){
PointerArray[i].onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
for(let j=0;j<OliArray.length;j++){
if(j!=i){
OliArray[j].style.zIndex = 0;
}
if(j!=next)
OliArray[j].style.opacity = 0;
if(j!=OliArray.length-1){
PointerArray[j].className = "";
}
}
OliArray[i].style.zIndex=1;
delayOpacity(OliArray[next],0,-0.1);
delayOpacity(OliArray[i],1,0.1);
PointerArray[i].className = "active";
pre = i - 1 == 0? OliArray.length-1:i-1;
next = i;
//开启自动轮播
autoPlay();
}
}html部分
<div class="banner-wapper">
<div class="container">
<div class="banner">
<ul class="img-list">
<li>
<a href="#">
<img src="./img/1.jpg" alt="">
</a>
</li>
<li>
<a href="#">
<img src="./img/2.jpg" alt="">
</a>
</li>
<li>
<a href="#">
<img src="./img/3.jpg" alt="">
</a>
</li>
<li>
<a href="#">
<img src="./img/4.jpg" alt="">
</a>
</li>
<li>
<a href="#">
<img src="./img/1.jpg" alt="">
</a>
</li>
</ul>
<div class="pointer">
<a href="javascript:;"></a>
<a href="javascript:;"></a>
<a href="javascript:;"></a>
<a href="javascript:;"></a>
</div>
<div class="prev-next">
<a class="prev" href="javascript:;"></a>
<a class="next" href="javascript:;"></a>
</div>
</div>
</div>
</div>CSS部分
.banner{
position: relative;
height: 460px;
}
.banner .img-list li{
position: absolute;
opacity: 0;
}
.banner-wapper .banner a img{
width: 1226px;
height: 460px;
vertical-align: top;
}
.banner .img-list li:nth-child(1){
opacity: 1;
}
.pointer{
z-index: 2;
position: absolute;
right: 30px;
bottom: 20px;
}
.pointer a{
float: left;
width: 6px;
height: 6px;
border: 2px rgba(255, 255, 255, 0.4) solid;
box-sizing: content-box;
margin: 0 4px;
border-radius: 50%;
background: rgba(0, 0, 0, 0.4);
}
.pointer a:hover,
.pointer .active{
border-color:rgba(0, 0, 0, 0.4);
background-color: rgba(255, 255, 255, 0.4);
}
.prev-next a{
width: 41px;
height: 69px;
position: absolute;
top: 0;
bottom: 0;
margin: auto 0;
background-image: url(../img/icon-slides.png);
}
.prev-next .prev{
z-index: 2;
left: 234px;
background-position: -84px 50%;
}
.prev-next .prev:hover{
background-position: 0 0;
}
.prev-next .next{
z-index: 2;
right: 0;
background-position: -125px 50%;
}
.prev-next .next:hover{
background-position: -42px 50%;
}js部分
window.onload = function(){
var Oul = document.getElementsByClassName("img-list")[0];
var OliArray = Oul.getElementsByTagName("li");
var pointer = document.getElementsByClassName("pointer")[0];
var PointerArray = pointer.getElementsByTagName("a");
var nextBanner = document.getElementsByClassName("next")[0];
var prevBanner = document.getElementsByClassName("prev")[0];
var timer,autoTimer, next = 0,pre = OliArray.length-1;
PointerArray[0].className = "active";
autoPlay();
// 点击轮播
for(let i=0;i<PointerArray.length;i++){
PointerArray[i].onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
for(let j=0;j<OliArray.length;j++){
if(j!=i){
OliArray[j].style.zIndex = 0;
}
if(j!=next)
OliArray[j].style.opacity = 0;
if(j!=OliArray.length-1){
PointerArray[j].className = "";
}
}
// console.log(pre,next,i)
OliArray[i].style.zIndex=1;
delayOpacity(OliArray[next],0,-0.1);
delayOpacity(OliArray[i],1,0.1);
PointerArray[i].className = "active";
pre = i - 1 == 0? OliArray.length-1:i-1;
next = i;
//开启自动轮播
autoPlay();
}
}
// 点击下一张
nextBanner.onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
next++;
pre++;
next %= OliArray.length;
pre %= OliArray.length;
if(pre==OliArray.length-1){
pre = 0;
}
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = "";
}
}
OliArray[next].style.zIndex = 1;
delayOpacity(OliArray[pre],0,-0.1);
delayOpacity(OliArray[next],1,0.1);
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;
}
PointerArray[next].className = "active";
//开启自动轮播
autoPlay();
}
//点击上一张
prevBanner.onclick = function(){
//将自动轮播的定时器清空
clearInterval(autoTimer);
pre = next;
next = next-1>=0? next-1:OliArray.length-2;
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = "";
}
}
OliArray[next].style.zIndex = 1;
delayOpacity(OliArray[pre],0,-0.1);
delayOpacity(OliArray[next],1,0.1);
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;
}
PointerArray[next].className = "active";
pre = next - 1;
//开启自动轮播
autoPlay();
}
// 自动轮播
function autoPlay(){
autoTimer = setInterval(function(){
next++;
pre++;
next %= OliArray.length;
pre %= OliArray.length;
if(pre==OliArray.length-1){
pre = 0;
}
for(let i=0;i<OliArray.length;i++){
if(i!=next){
OliArray[i].style.zIndex = 0;
}
if(i!=pre)
OliArray[i].style.opacity = 0;
if(i!=OliArray.length-1){
PointerArray[i].className = "";
}
}
OliArray[next].style.zIndex=1;
delayOpacity(OliArray[pre],0,-0.1);
delayOpacity(OliArray[next],1,0.1);
if(next==OliArray.length-1) {
next = 0;
OliArray[next].style.opacity = 1;
}
PointerArray[next].className = "active";
},3000);
}
function delayOpacity(obj,target,speed){
clearInterval(timer);
timer = setInterval(function(){
var old = getComputedStyle(obj,null)['opacity'];
// console.log(getComputedStyle(obj,null)['opacity'])
var newVal = +old + +speed;
// console.log(obj,newVal)
if(parseInt(speed)>0 && newVal>=target){
newVal = 1;
}
if(parseInt(speed)<0 && newVal<=target){
newVal = 0;
}
obj.style.opacity = newVal;
// console.log(getComputedStyle(obj,null)['opacity'])
if(newVal==target){
clearInterval(timer);
}
},100);
}
}以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程网。
