FadeIn() images in slideshow using jquery

问题

I am working on an image slideshow, and the fadeOut() functionality working with every image change, but the next image appears abruptly. I want it to fade in. I can't seem to get it working.

Here is the code without any fadeIn():

HTML:

<div id="backgroundChanger">
  <img class="active" src="background1.jpg"/>
  <img src="background2.jpg"/>  
  <img src="background3.jpg"/>

CSS:

#backgroundChanger{
 position:relative;
}
#backgroundChanger img{
 position:absolute;
 z-index:-3
}
#backgroundChanger img.active{
 z-index:-1;
}

Javascript:

function cycleImages(){
      var $active = $('#backgroundChanger .active');
      var $next = ($active.next().length > 0) ? $active.next() : $('#backgroundChanger img:first');
      $next.css('z-index',-2);
      $active.fadeOut(1500,function(){
      $active.css('z-index',-3).show().removeClass('active');
          $next.css('z-index',-1).addClass('active');
      });
    }

$(document).ready(function(){
 setInterval('cycleImages()', 7000);
})

回答1:

I'd recommend something like this for your interval function:

window.setInterval(function (){
  var images = $('#backgroundChanger img');
  var active, next;

  images.each(function(index, img) {
    if($(img).hasClass('active')) {
      active = index;
      next = (index === images.length - 1) ? 0 : index + 1;
    }
  });

  $(images[active]).fadeOut(1000, function() {
    $(images[next]).fadeIn(1000);
  });

  $(images[next]).addClass('active');
  $(images[active]).removeClass('active');
}, 3000);

And this is all you'd need for your css:

#backgroundChanger img:first-child {
  display: block;
}

#backgroundChanger img {
  display: none;
}

And keep the same HTML and you should be good to go!

回答2:

You can fadeIn() the next image in the callback of fadeOut() as shown below:

$(window).load(function() {
  var $slider = $("#backgroundChanger"),
    $slides = $slider.find("img"),
    $firstSlide = $slides.first();

  function cycleImages() {
    var $active = $('#backgroundChanger .active'),
      $next = ($active.next().length > 0) ? $active.next() : $firstSlide;
    $active.fadeOut(1000, function() {
      $active.removeClass('active');
      $next.fadeIn(1000).addClass('active');
    });
  }

  setInterval(cycleImages, 3000);
})

#backgroundChanger img {
  position: absolute;
  width: 150px;
  height: 100px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="backgroundChanger">
  <img class="active" src="http://i46.tinypic.com/2epim8j.jpg" />
  <img src="http://i49.tinypic.com/28vepvr.jpg" />
  <img src="http://i50.tinypic.com/f0ud01.jpg" />
</div>

Notes:

Since we're dealing with images, It's better to use load() handler than ready() to make sure the slide show starts after the images are loaded
You can slightly improve the performance by caching the elements accessed frequently
You don't have to play with z-index property at all since both fadeIn() and fadeOut() changes the elements `display property itself

来源：https://stackoverflow.com/questions/22430281/fadein-images-in-slideshow-using-jquery

标签

javascript

css

background

fadein

fadeout