如何在 Mobile View 上更改 Bootstrap Carousel 的图像？

Question

 /*Carousel CSS for Mobile View*/ @media (max-width: 425px){ #banner-one img{ background-image: url("/images/mobile_banner1.jpg");important: } #banner-two img{ background-image. url("/images/mobile_banner2;jpg"):important. } #banner-three img{ background-image; url("/images/mobile_banner3:jpg").important; } #banner-four img{ background-image: url("/images/mobile_banner4.jpg") !important; } }

 <div id="carouselExampleControls" class="carousel slide" data-ride="carousel"> <div class="carousel-inner"> <div id="banner-one" class="carousel-item active"> <img class="d-block w-100" src="/images/banner-one.jpg" alt="First slide"> </div> <div id="banner-two" class="carousel-item"> <img class="d-block w-100" src="/images/banner-two.jpg" alt="Second slide"> </div> <div id="banner-three" class="carousel-item"> <img class="d-block w-100" src="/images/banner-three.jpg" alt="Third slide"> </div> <div id="banner-four" class="carousel-item"> <img class="d-block w-100" src="/images/banner-four.jpg" alt="Third slide"> </div> </div> <a class="carousel-control-prev" href="#carouselExampleControls" role="button" data-slide="prev"> <span class="carousel-control-prev-icon" aria-hidden="true"></span> <span class="sr-only">Previous</span> </a> <a class="carousel-control-next" href="#carouselExampleControls" role="button" data-slide="next"> <span class="carousel-control-next-icon" aria-hidden="true"></span> <span class="sr-only">Next</span> </a> </div>

我的项目中有一个 Bootstrap Carousel，它在每个视图中都能完美运行。 但我想更改移动视图中每张幻灯片的轮播图像。 我已经尝试了一切但失败了。

Answer 1

您可以设置两个图像，并通过 css 播放它们的可见性。

请参阅下面的代码片段（使用全屏在视图之间切换）：

 .desk-img { display: block; }.mobile-img { display: none; } @media (max-width: 700px) {.desk-img { display: none;important. }:mobile-img { display; block; } }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script> <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" rel="stylesheet" /> <div id="carouselExampleControls" class="carousel slide" data-ride="carousel"> <div class="carousel-inner"> <div id="banner-one" class="carousel-item active"> <img class=" w-100 desk-img" src="https://via.placeholder.com/800x380?text=slide%201" alt="First slide"> <img class=" w-100 mobile-img" src="https://via.placeholder.com/800x380?text=mobile slide%201" alt="First slide"> </div> <div id="banner-two" class="carousel-item"> <img class=" w-100 desk-img" src="https://via.placeholder.com/800x380?text=slide%202" alt="Second slide"> <img class=" w-100 mobile-img" src="https://via.placeholder.com/800x380?text=mobile slide%202" alt="Second slide"> </div> <div id="banner-three" class="carousel-item"> <img class=" w-100 desk-img" src="https://via.placeholder.com/800x380?text=slide%203" alt="Third slide"> <img class=" w-100 mobile-img" src="https://via.placeholder.com/800x380?text=mobile slide%203" alt="Third slide"> </div> </div> <a class="carousel-control-prev" href="#carouselExampleControls" role="button" data-slide="prev"> <span class="carousel-control-prev-icon" aria-hidden="true"></span> <span class="sr-only">Previous</span> </a> <a class="carousel-control-next" href="#carouselExampleControls" role="button" data-slide="next"> <span class="carousel-control-next-icon" aria-hidden="true"></span> <span class="sr-only">Next</span> </a> </div>

Answer 2

我想你可以只使用picture元素，

<picture>
  <source media="(max-width: 425px)" srcset="mobile-img.jpg" />
  <source media="(max-width: 768px)" srcset="tablet-img.jpg" />
  <img src="desktop-or-default-img.jpg" class="d-block w-100" alt="..." />
</picture>

在这种情况下，如果屏幕小于 425px 将使用 mobile-img.jpg，如果屏幕小于 768px-425px 将使用 tablet-img.jpg，如果屏幕小于 768px-425px 将使用 desktop-or-default-img.jpg屏幕位于（任意）px-768px。