尝试为图像幻灯片制作不可见的前进和后退按钮

Question

我希望幻灯片放映按钮如何运行的屏幕截图：

我正在尝试为我的幻灯片创建前进和后退按钮，这些按钮是不可见的并且跨越图像到页面边缘。但是我不知道该怎么做。

我尝试使用 flexbox，父元素是图像容器，子元素是按钮。然而，每次我插入这些属性时，按钮都消失了，我再也无法点击或找到按钮了。

这是我的 html:

<!-- Slideshow container -->
<div class="slideshow-container">

  <!-- Full-width images with number and caption text -->
  <div class="mySlides">
    <div class="numbertext">1 / 3</div>
    <img src="img/3.jpg" style="width:100%">
    <div class="text">Caption Text</div>
  </div>

  <div class="mySlides">
    <div class="numbertext">2 / 3</div>
    <img src="img/30.JPG" style="width:100%">
    <div class="text">Caption Two</div>
  </div>

  <div class="mySlides">
    <div class="numbertext">3 / 3</div>
    <img src="img/39.jpg" style="width:100%">
    <div class="text">Caption Three</div>
  </div>

  <!-- Next and previous buttons -->
  <div class="prev" onclick="plusSlides(-1)"></div>
  <div class="next" onclick="plusSlides(1)"></div>
</div>

这是我的 CSS：

* {box-sizing:border-box}

/* Slideshow container */
.slideshow-container {
  max-width: 30%;
  max-height: 30%;
  position: relative;
  margin: auto;
  margin-top: 20vh;
  margin-bottom: 20vh;
  justify-content: space-between;
  display: flex;
}

/* Hide the images by default */
.mySlides {
  display: none;
}

/* Next & previous buttons */
.prev, .next {
  cursor: pointer;
  flex: 1;
  user-select: none;
}

这是我的 JS：

let slideIndex = 1;
showSlides(slideIndex);

// Next/previous controls
function plusSlides(n) {
  showSlides(slideIndex += n);
}

// Thumbnail image controls
function currentSlide(n) {
  showSlides(slideIndex = n);
}

function showSlides(n) {
  let i;
  let slides = document.getElementsByClassName("mySlides");
  let dots = document.getElementsByClassName("dot");
  if (n > slides.length) {slideIndex = 1}
  if (n < 1) {slideIndex = slides.length}
  for (i = 0; i < slides.length; i++) {
    slides[i].style.display = "none";
  }
  for (i = 0; i < dots.length; i++) {
    dots[i].className = dots[i].className.replace(" active", "");
  }
  slides[slideIndex-1].style.display = "block";
  dots[slideIndex-1].className += " active";
}

Answer 1

尝试使用

position: absolute;

作为按钮，我做了一个例子如下：

let slideIndex = 1;
showSlides(slideIndex);

// Next/previous controls
function plusSlides(n) {
  showSlides(slideIndex += n);
}

// Thumbnail image controls
function currentSlide(n) {
  showSlides(slideIndex = n);
}

function showSlides(n) {
  let i;
  let slides = document.getElementsByClassName("mySlides");
  let dots = document.getElementsByClassName("dot");
  if (n > slides.length) {slideIndex = 1}
  if (n < 1) {slideIndex = slides.length}
  for (i = 0; i < slides.length; i++) {
    slides[i].style.display = "none";
  }
  for (i = 0; i < dots.length; i++) {
    dots[i].className = dots[i].className.replace(" active", "");
  }
  slides[slideIndex-1].style.display = "block";
  dots[slideIndex-1].className += " active";
}

* {box-sizing:border-box}

/* Slideshow container */
.slideshow-container {
  max-width: 30%;
  max-height: 30%;
  position: relative;
  margin: auto;
  margin-top: 20vh;
  margin-bottom: 20vh;
  justify-content: space-between;
  display: flex;
}

/* Hide the images by default */
.mySlides {
  display: none;
}


/* Next and previous buttons */
.prev, .next {
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: 1;
  cursor: pointer;
  width: 50%;
  height: 100%;
  background-color: transparent;
}

.prev {
  left: 0;
}

.next {
  right: 0;
}

/* Hide button elements by default */
.prev, .next {
  opacity: 0;
  transition: opacity 0.3s ease;
}

/* Show button elements on hover */
.slideshow-container:hover .prev, .slideshow-container:hover .next {
  opacity: 1;
}

<!-- Slideshow container -->
<div class="slideshow-container">

  <!-- Full-width images with number and caption text -->
  <div class="mySlides">
    <div class="numbertext">1 / 3</div>
    <img src="img/3.jpg" style="width:100%">
    <div class="text">Caption Text</div>
  </div>

  <div class="mySlides">
    <div class="numbertext">2 / 3</div>
    <img src="img/30.JPG" style="width:100%">
    <div class="text">Caption Two</div>
  </div>

  <div class="mySlides">
    <div class="numbertext">3 / 3</div>
    <img src="img/39.jpg" style="width:100%">
    <div class="text">Caption Three</div>
  </div>

  <!-- Next and previous buttons -->
  <div class="prev" onclick="plusSlides(-1)"></div>
  <div class="next" onclick="plusSlides(1)"></div>
</div>

我想这就是你想要的，但提醒你，你的JS代码中的点似乎是不必要的，它会导致错误。我建议你删除这些代码。

Answer 2

你只需要在 JS 点变量中使用

mySlides

类而不是

dot

。 并且在 css 中有一些更正，如下所述：

请参考此链接进行现场演示以了解详细信息。 https://jsfiddle.net/76L4phfc/

.prev,
.next {
    background: red;
    opacity: 0.2;
    z-index: 55555;
    width: 48%;
    height: 100%;
    display: block;
    position: absolute;
}
.next { right: 0;}
.prev { left: 0;}