twitter-bootstrap 延迟加载在引导轮播中不起作用
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lazy load not work in bootstrap carousel
提问by Pink Code
I create carousel using bootstrap 3 like this :
我像这样使用引导程序 3 创建轮播：
HTML :
HTML :
<div id="myCarousel" class="carousel slide">
<div class="carousel-inner">
<div class="active item">
<img src="http://rivathemes.net/html/envor/img/posts/3.jpg" class="img-big">
</div>
<div class="item">
<img data-lazy-load-src="http://rivathemes.net/html/envor/img/posts/4.jpg" class="img-big">
</div>
</div>
<div class="carousel-controls">
<a class="left carousel-control" href="#myCarousel" data-slide="prev"><i class="fa fa-angle-double-left fa-lg"></i></a>
<a class="right carousel-control" href="#myCarousel" data-slide="next"><i class="fa fa-angle-double-right fa-lg"></i></a>
</div>
</div>
and add this code for add imglazy load.
并添加此代码以添加img延迟加载。
JS :
JS：
$('#myCarousel').on('slid', function () {
var $nextImage = $('.active.item', this).next('.item').find('img');
$nextImage.attr('src', $nextImage.data('lazy-load-src'));
});
But, This not work for me!? can do fix this ?
但是，这对我不起作用！？可以解决这个问题吗？
Important Q: can i add image preloader for lazy load?!
重要问题：我可以为延迟加载添加图像预加载器吗？！
DEMO : FIDDLE
演示：小提琴
采纳答案by dm4web
- add
lazy-loadclass to item object - use
slide.bs.carouselevent
- 将
lazy-load类添加到项目对象 - 使用
slide.bs.carousel事件
CSS:
CSS：
.lazy-load {
background: url("http://www.mozart.it/images/preloader.gif") center center no-repeat;
}
JQ:
江青：
var cHeight = 0;
$('#myCarousel').on('slide.bs.carousel', function (e) {
var $nextImage = null;
$activeItem = $('.active.item', this);
if (e.direction == 'left'){
$nextImage = $activeItem.next('.item').find('img');
} else {
if ($activeItem.index() == 0){
$nextImage = $('img:last', $activeItem.parent());
} else {
$nextImage = $activeItem.prev('.item').find('img');
}
}
// prevents the slide decrease in height
if (cHeight == 0) {
cHeight = $(this).height();
$activeItem.next('.item').height(cHeight);
}
// prevents the loaded image if it is already loaded
var src = $nextImage.data('lazy-load-src');
if (typeof src !== "undefined" && src != "") {
$nextImage.attr('src', src)
$nextImage.data('lazy-load-src', '');
}
});
回答by cmeeren
The answer by dm4webdoes not account for skipping slides by directly clicking the carousel indicators. This version correctly loads an image regardless of how you slide to it, using Bootstrap's event.relatedTarget(the item being slid into place, see the official documentation). Try running the snippet below and clicking on the indicators to switch several slides ahead.
dm4web的答案没有考虑通过直接单击轮播指示器来跳过幻灯片。无论您如何滑动，此版本都会正确加载图像，使用 Bootstrap 的event.relatedTarget（滑动到位的项目，请参阅官方文档）。尝试运行下面的代码段并单击指标以切换多张幻灯片。
var cHeight = 0;
$('#carousel-example-generic').on('slide.bs.carousel', function(e) {
var $nextImage = $(e.relatedTarget).find('img');
$activeItem = $('.active.item', this);
// prevents the slide decrease in height
if (cHeight == 0) {
cHeight = $(this).height();
$activeItem.next('.item').height(cHeight);
}
// prevents the loaded image if it is already loaded
var src = $nextImage.data('lazy-load-src');
if (typeof src !== "undefined" && src != "") {
$nextImage.attr('src', src)
$nextImage.data('lazy-load-src', '');
}
});<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<div class="container-fluid">
<div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
<!-- Indicators -->
<ol class="carousel-indicators">
<li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
<li data-target="#carousel-example-generic" data-slide-to="1"></li>
<li data-target="#carousel-example-generic" data-slide-to="2"></li>
<li data-target="#carousel-example-generic" data-slide-to="3"></li>
<li data-target="#carousel-example-generic" data-slide-to="4"></li>
</ol>
<!-- Wrapper for slides -->
<div class="carousel-inner" role="listbox">
<div class="item active">
<img src="http://placehold.it/5000x1000">
</div>
<div class="item">
<img data-lazy-load-src="http://placehold.it/5001x1000">
</div>
<div class="item">
<img data-lazy-load-src="http://placehold.it/5002x1000">
</div>
<div class="item">
<img data-lazy-load-src="http://placehold.it/5003x1000">
</div>
<div class="item">
<img data-lazy-load-src="http://placehold.it/5004x1000">
</div>
</div>
<!-- Controls -->
<a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
<span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
</div>回答by ArGh
If you have multiple images in your slide, you have to use this :
如果幻灯片中有多个图像，则必须使用以下命令：
var cHeight = 0;
$('#carousel').on('slide.bs.carousel', function (e) {
var $nextImage = null;
$activeItem = $('.active.item', this);
if (e.direction == 'left'){
$nextImage = $activeItem.next('.item').find('img');
} else {
if ($activeItem.index() == 0){
$nextImage = $('img:last', $activeItem.parent());
} else {
$nextImage = $activeItem.prev('.item').find('img');
}
}
// prevents the slide decrease in height
if (cHeight == 0) {
cHeight = $(this).height();
$activeItem.next('.item').height(cHeight);
}
// => Changes here !
// prevents the loaded images if it is already loaded
$nextImage.each(function(){
var $this = $(this),
src = $this.data('original');
if (typeof src !== "undefined" && src != "") {
$this.attr('src', src)
$this.data('original', '');
}
});
});
回答by joe
Created this "kinda generic" solution some months ago and had no issues so far...
几个月前创建了这个“有点通用”的解决方案，到目前为止没有任何问题......
var $ajaxCarousel = $('.carousel-ajax');
if ($ajaxCarousel.length > 0) {
$ajaxCarousel.on('slide.bs.carousel', function (e) {
var $upcomingImage = $(e.relatedTarget).find('img');
if (typeof $upcomingImage.attr('src') === 'undefined') {
$upcomingImage.attr('src', $upcomingImage.data('src'));
}
});
// preload first image
$ajaxCarousel.each(function() {
var $firstImage = $(this).find('[data-slide-number=0]').find('img');
$firstImage.attr('src', $firstImage.data('src'));
});
}
All you have to do in HTML is add "carousel-ajax" class to your existing carousel and prepend "data-" in front of your img's src tags:
您在 HTML 中要做的就是将“carousel-ajax”类添加到现有的轮播中，并在 img 的 src 标签前添加“data-”：
<img data-src="..." />
