Bootstrap 4.0.0 Carousel fade transition

问题:

There are several questions asked on Stackoverflow regarding Carousel fade transition but none of them seem to work on a default 4.0.0 implementation:

<div id="carouselExampleIndicators" class="carousel slide" data-ride="carousel">
  <ol class="carousel-indicators">
    <li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
  </ol>
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img class="d-block w-100" src="..." alt="First slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="..." alt="Second slide">
    </div>
    <div class="carousel-item">
      <img class="d-block w-100" src="..." alt="Third slide">
    </div>
  </div>
  <a class="carousel-control-prev" href="#carouselExampleIndicators" 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="#carouselExampleIndicators" role="button" data-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="sr-only">Next</span>
  </a>
</div>

Did bootstrap change the way of transitioning carousel-item -s since Alpha.6 version? How would one go about implementing the fade transition instead of slide in 4.0.0 ?

回答1:

I reopened this because the question was changed from 4 Beta to 4.0.0 (stable)...

Bootstrap 4.0.0 Carousel Fade:
https://www.codeply.com/go/LhLJlldsLN

.carousel-fade .carousel-item {
 opacity: 0;
 transition-duration: .6s;
 transition-property: opacity;
}

.carousel-fade  .carousel-item.active,
.carousel-fade  .carousel-item-next.carousel-item-left,
.carousel-fade  .carousel-item-prev.carousel-item-right {
  opacity: 1;
}

.carousel-fade .active.carousel-item-left,
.carousel-fade  .active.carousel-item-right {
 opacity: 0;
}

.carousel-fade  .carousel-item-next,
.carousel-fade .carousel-item-prev,
.carousel-fade .carousel-item.active,
.carousel-fade .active.carousel-item-left,
.carousel-fade  .active.carousel-item-prev {
 transform: translateX(0);
 transform: translate3d(0, 0, 0);
}

---

The fade effect was removed from the carousel during the 4.0 Beta and is also not available in 4.0.0. This pull request indicates that the fade effect will return in 4.1 or 4.2. In the meanwhile, the above CSS will work for 4.0.0

回答2:

In bootstrap 4, you can add "carousel-fade" class like this.

<div id="carouselExampleIndicators" class="carousel slide carousel-fade" data-ride="carousel"> 
....
</div>

回答3:

Should be fixed in Bootstrap 4.1.

https://blog.getbootstrap.com/2018/04/09/bootstrap-4-1/