JavaScript仿小米輪播圖效果
本文是自己仿寫(xiě)的小米輪播圖的寫(xiě)法,通過(guò)透明度改變進(jìn)行輪播的,新手,寫(xiě)的可能不是很好,有啥不合理的情況,望提出,指正,全部的代碼放最下面
有很多寫(xiě)法重復(fù),有空的時(shí)候,我把重復(fù)的代碼封裝一下
關(guān)于透明度漸變的動(dòng)畫(huà)效果
比如 delayOpacity(OliArray[pre],0,-0.1); 就是將OliArray[pre]這個(gè)對(duì)象的透明度轉(zhuǎn)換成0,速度為0.1
function delayOpacity(obj,target,speed){ clearInterval(timer); timer = setInterval(function(){ var old = getComputedStyle(obj,null)['opacity']; var newVal = +old + +speed;//+是將字符串轉(zhuǎn)變成number類型 if(parseInt(speed)>0 && newVal>=target){ newVal = 1; } if(parseInt(speed)<0 && newVal<=target){ newVal = 0; } obj.style.opacity = newVal;//每次將新的值賦值給該對(duì)象的透明度,產(chǎn)生漸變效果 if(newVal==target){ clearInterval(timer);//當(dāng)透明度的值和目標(biāo)中的透明度的值一樣的時(shí)候,將定時(shí)器關(guān)閉 } },100); }
關(guān)于自動(dòng)輪播的方法
我的輪播有四張,但是寫(xiě)了五張圖片,第五張和第一張圖片是一樣的,目的是為了透明度轉(zhuǎn)換的比較合理,不會(huì)突然從最后一張變到第一張
全局變量 next代表輪播圖將要切換的那一張,pre代表輪播圖目前的這張
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; /*解決點(diǎn)擊前幾張圖片時(shí),之后自動(dòng)輪播沒(méi)有切換效果的問(wèn)題, 由于后面的圖片顯示的效果在前面的圖片之上,所以如果在播放到第三張圖片時(shí), 點(diǎn)擊第一張圖片后,自動(dòng)輪播時(shí),因?yàn)榈谌龔垐D片的顯示在第二張圖片之上 所以從第一張到第二張,是沒(méi)有動(dòng)畫(huà)效果,且圖片一直停在第三張 所以要把將要顯示的圖片的層級(jí)設(shè)置為1,其他圖片的層級(jí)設(shè)置為0*/ } if(i!=pre) OliArray[i].style.opacity = 0; if(i!=OliArray.length-1){ PointerArray[i].className = ""; //這個(gè)是點(diǎn)擊時(shí),除點(diǎn)擊的那個(gè)原點(diǎn)外,其他的激活的樣式清空 } } OliArray[next].style.zIndex=1; delayOpacity(OliArray[pre],0,-0.1);//將上一張的透明度由1變成0 delayOpacity(OliArray[next],1,0.1);//將要顯示的圖片的透明度由0變成1 if(next==OliArray.length-1) { next = 0; OliArray[next].style.opacity = 1;//到最后一張圖片的時(shí)候,立即切換到第一張,相對(duì)于假裝輪播到第一張了,因?yàn)橛脩舻难劬](méi)有那么亮 } PointerArray[next].className = "active"; },3000); }
關(guān)于點(diǎn)擊上一張圖片
prevBanner.onclick = function(){ //將自動(dòng)輪播的定時(shí)器清空 clearInterval(autoTimer); pre = next;//此時(shí)的pre就是原來(lái)切換到的那張圖片 next = next-1>=0? next-1:OliArray.length-2;//next就是上一張,要切換的圖片 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; //開(kāi)啟自動(dòng)輪播 autoPlay(); }
關(guān)于點(diǎn)擊下一張
和自動(dòng)輪播有點(diǎn)像,但是沒(méi)有定時(shí)器(這里我覺(jué)得可以封裝函數(shù)來(lái)寫(xiě),以后改一下)
nextBanner.onclick = function(){ //將自動(dòng)輪播的定時(shí)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"; //開(kāi)啟自動(dòng)輪播 autoPlay(); }
關(guān)于點(diǎn)擊某個(gè)原點(diǎn),切換到該原點(diǎn)的圖片
for(let i=0;i<PointerArray.length;i++){ PointerArray[i].onclick = function(){ //將自動(dòng)輪播的定時(shí)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; //開(kāi)啟自動(dòng)輪播 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(); // 點(diǎn)擊輪播 for(let i=0;i<PointerArray.length;i++){ PointerArray[i].onclick = function(){ //將自動(dòng)輪播的定時(shí)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; //開(kāi)啟自動(dòng)輪播 autoPlay(); } } // 點(diǎn)擊下一張 nextBanner.onclick = function(){ //將自動(dòng)輪播的定時(shí)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"; //開(kāi)啟自動(dòng)輪播 autoPlay(); } //點(diǎn)擊上一張 prevBanner.onclick = function(){ //將自動(dòng)輪播的定時(shí)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; //開(kāi)啟自動(dòng)輪播 autoPlay(); } // 自動(dòng)輪播 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); } }
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