如何向此幻灯片脚本添加不透明度过渡?第 2 部分

Question

再问一次。我已经取得了一些进展，但不幸的是我仍然无法完成它，我有点绝望。

我昨天问的问题可以在这里找到：如何向此脚本添加不透明度过渡？

正如 Anthony 建议的那样，我试图为"mySlides"的可见 img 提供一个名为 .visible 的额外类，并在调用下一个 img 时将其删除。

所以经过一番研究，我设法给它一个新的类：x[slideIndex-1].classList.add("visible"(

但过渡仍然行不通。

我做错了什么？

var slideIndex = 1;
showDivs(slideIndex);
function plusDivs(n) {
showDivs(slideIndex += n);
}
function currentDiv(n) {
showDivs(slideIndex = n);
}
function showDivs(n) {
var i,
x = document.getElementsByClassName("mySlides"),
dots = document.getElementsByClassName("demo");
if (n > x.length) {
slideIndex = 1
}
if (n < 1) {
slideIndex = x.length
}
for (i = 0; i < x.length; i++) {
x[i].style.display = "none";
x[i].classList.remove("visible");
}
for (i = 0; i < dots.length; i++) {
dots[i].className = dots[i].className.replace(" w3-white", "");
}
x[slideIndex - 1].style.display = "block";
x[slideIndex - 1].classList.add("visible")
dots[slideIndex - 1].className += " w3-white";
}

img.mySlides {
opacity: 0;
transition: opacity 2s;
}
img.mySlides.visible {
opacity: 1;
transition: opacity 2s
}

<div class="w3-content w3-display-container">
<div id="slider-wrapper">
<img id="zupfinstrumente" class="centerscreen mySlides slidepos" src="img1.jpg" alt="xy">
<img id="ueber-mich" class="centerscreen mySlides slidepos" src="img2.jpg" alt="xy">
<img id="streichinstrumente" class="centerscreen mySlides slidepos" src="img3.jpg" alt="xy"></div>
<div class="w3-center w3-container w3-section w3-large w3-text-white centerscreen badgepos">
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(1)"></span>
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(2)"></span>
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(3)"></span>
</div>
<container id="buttons" class="centerscreen">
<div id="navarrow-left" class="w3-left w3-hover-text-black btn" onclick="plusDivs(-1)">&#10094;</div>
<div id="navarrow-right" class="w3-right w3-hover-text-black btn" onclick="plusDivs(1)">&#10095;</div>
</container>
</div>

Answer 1

您可以创建托管的 css 周年纪念，然后在您的imgwo 上使用最后一个，当显示的图像时，该公告将触发，

公告 CSS 代码 ：

/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
@-webkit-keyframes fade {
from {opacity: .4} 
to {opacity: 1}
}
@keyframes fade {
from {opacity: .4} 
to {opacity: 1}
}

请参阅下面的片段：

var slideIndex = 1;
	showDivs(slideIndex);
function plusDivs(n) {
	showDivs(slideIndex += n);
}
function currentDiv(n) {
	showDivs(slideIndex = n);
}
function showDivs(n) {
	var i,
		x = document.getElementsByClassName("mySlides"),
		dots = document.getElementsByClassName("demo");
	
	if (n > x.length) {slideIndex = 1
	} 
	
	if (n < 1) {slideIndex = x.length
	}
	
	for (i = 0; i < x.length; i++) {
		x[i].style.display = "none";
	}
	
	for (i = 0; i < dots.length; i++) {
	  dots[i].className = dots[i].className.replace(" w3-white", "");
	}
	 
	x[slideIndex-1].style.display = "block";
	dots[slideIndex-1].className += " w3-white";
}

.mySlides {display:none}
.w3-left, .w3-right, .w3-badge {cursor:pointer}
.w3-badge {height:13px;width:13px;padding:0}
/* Fading animation */
.fade {
-webkit-animation-name: fade;
-webkit-animation-duration: 1.5s;
animation-name: fade;
animation-duration: 1.5s;
}
@-webkit-keyframes fade {
from {opacity: .1} 
to {opacity: 1}
}
@keyframes fade {
from {opacity: .1} 
to {opacity: 1}
}

<link href="https://www.w3schools.com/w3css/4/w3.css" rel="stylesheet"/>
<div class="w3-content w3-display-container">
<div id="slider-wrapper">
<img id="zupfinstrumente" class="centerscreen mySlides slidepos fade" src="https://www.w3schools.com/w3css/img_mountains_wide.jpg" alt="xy">
<img id="ueber-mich" class="centerscreen mySlides slidepos fade" src="https://www.w3schools.com/w3css/img_fjords_wide.jpg" alt="xy">
<img id="streichinstrumente" class="centerscreen mySlides slidepos fade" src="https://www.w3schools.com/w3css/img_nature_wide.jpg" alt="xy"></div>
<div class="w3-center w3-container w3-section w3-large w3-text-white centerscreen badgepos">
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(1)"></span>
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(2)"></span>
<span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(3)"></span>
</div>
<container id="buttons" class="centerscreen">
<div id="navarrow-left" class="w3-left w3-hover-text-black btn" onclick="plusDivs(-1)">&#10094;</div>
<div id="navarrow-right" class="w3-right w3-hover-text-black btn" onclick="plusDivs(1)">&#10095;</div>
</container>
</div>