javascript - 具有不同幻灯片时间的幻灯片放映

Question

编辑:

我目前正在与 Louys Patrice Besette 的解答者合作，我几乎完成了所有幻灯片的制作。但是有时当我刷新页面时。视频变黑，无法播放。这适用于所有下一个即将发布的视频。然后刷新几次后它又可以工作了。

为什么会这样？

当错误(黑色视频)发生时，我在控制台中收到此错误:index.html:1 Uncaught (in promise) DOMException: The play() request was interrupted by a call to pause().

还有一个问题。是否有一种方法可以像等待装载的东西一样排队？我现在已完成网站的 60-70%。但是，我注意到我的笔记本电脑必须非常非常非常努力地工作才能第一次加载所有视频和图像。

编辑结束

现在我正在尝试制作一种幻灯片放映来逐一显示图像和视频。

到目前为止，我的代码如下所示:

HTML:

<div id="div1" class="hidden">
    <video autoplay>
        <source src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4" type="video/mp4">
    </video>
</div>
<div id="div2" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>
<div id="div3" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>
<div id="div4" class="hidden">
    <video autoplay>
        <source src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4" type="video/mp4">
    </video>
</div>
<div id="div5" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>
<div id="div6" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>
<div id="div7" class="hidden">
    <video autoplay>
        <source src="http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4" type="video/mp4">
    </video>
</div>
<div id="div8" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>
<div id="div9" class="hidden"><img src="http://www.w3schools.com/css/trolltunga.jpg" /></div>

这段代码收集了 9 张“幻灯片”。 3 个视频和 7 个图像。我想在网页上一一显示(每个显示不同的时间)。

我通过以下方式做到这一点:

脚本:

<script type="text/javascript">
    //show first slide
    function showIt() {
        document.getElementById("div1").className = "shown";
    }
    setTimeout("showIt()", 0000);

    //Start fading first slide
    function hideIt() {
        document.getElementById("div1").className = "fade";
    }
    setTimeout("hideIt()", 16000);

    //Start showing 2nd slide
    function showIt2() {
        document.getElementById("div2").className = "shown";
    }
    setTimeout("showIt2()", 16500);

    //Remove the first slide
    function removeIt() {
        document.getElementById("div1").className = "hidden";
    }
    setTimeout("removeIt()", 17000);

    //Start fading second slide
    function hideIt2() {
        document.getElementById("div2").className = "fade";
    }
    setTimeout("hideIt2()", 27000);

    //Remove the second slide
    function removeIt2() {
        document.getElementById("div1").className = "hidden";
    }
    setTimeout("removeIt2()", 28000);

    //When end is reached, reload page
    setTimeout(window.location.reload.bind(window.location), 28000);
</script>

和 Css:

img {
    max-width: 78%;
    position:absolute;
    margin-left: 10.5%;
}

video {
    max-width: 78%;
    position:absolute;
    margin-left: 10.5%;
}

.hidden{
    visibility: hidden;
}

.fade{
    -webkit-animation: fadeout 1s; /* Safari, Chrome and Opera > 12.1 */
       -moz-animation: fadeout 1s; /* Firefox < 16 */
        -ms-animation: fadeout 1s; /* Internet Explorer */
         -o-animation: fadeout 1s; /* Opera < 12.1 */
            animation: fadeout 1s;
}

@keyframes fadeout {
    from { opacity: 1; }
    to   { opacity: 0; }
}

/* Firefox < 16 */
@-moz-keyframes fadeout {
    from { opacity: 1; }
    to   { opacity: 0; }
}

/* Safari, Chrome and Opera > 12.1 */
@-webkit-keyframes fadeout {
    from { opacity: 1; }
    to   { opacity: 0; }
}

/* Internet Explorer */
@-ms-keyframes fadeout {
    from { opacity: 1; }
    to   { opacity: 0; }
}

/* Opera < 12.1 */
@-o-keyframes fadeout {
    from { opacity: 1; }
    to   { opacity: 0; }
}


.shown{
    -webkit-animation: fadein 1s; /* Safari, Chrome and Opera > 12.1 */
       -moz-animation: fadein 1s; /* Firefox < 16 */
        -ms-animation: fadein 1s; /* Internet Explorer */
         -o-animation: fadein 1s; /* Opera < 12.1 */
            animation: fadein 1s;
}

@keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* Firefox < 16 */
@-moz-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* Safari, Chrome and Opera > 12.1 */
@-webkit-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* Internet Explorer */
@-ms-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* Opera < 12.1 */
@-o-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }
}

如您所见，我现在只显示 2 张幻灯片。虽然我有 9 准备。 (我总共有 40+)。如果我继续走我现在走的路。我会得到成吨成吨的代码……

问题:

Is there a way to make this more compact/smaller?

I searched the internet for slideshows and find things. However i want to set the time to be seen for each slide. Since some slides need to be displayed 20 seconds and other 10.

我也做了一个 fiddle ，但它在那里不起作用...... https://jsfiddle.net/a10yarxj/

Answer 1

我理解，在您的问题中，您想完全控制幻灯片放映时间。
显示时间...
我还添加了淡入/淡出时间也不同的可能性。

幻灯片将包含图像或视频，可能会比您的时间长...在显示其他幻灯片时让声音继续。

我想图像/视频的顺序可能(并且将会!)随时间改变......
并且滑动量是可变的。

所以我制作了这个小脚本，您每次更改幻灯片内容时都不必修改。
HTML 中提供了所有参数:

• 数据计时(以秒为单位的时间)
• 数据淡入(以秒为单位的时间)
• 数据淡出(以秒为单位的时间)
• 数据视频暂停(真/假)

对于前 3 个参数，如果缺少值，将应用默认时间，并在 console.log() 中显示 «NOTICE»。
最后，如果缺失，则视为假。

我使用 jQuery .animate() 而不是 CSS @keyframes 因为这样更容易实现效果，因为只有 opacity受到影响。

幻灯片正在循环播放...所以最后不需要加载新页面。

在这里，在下面的代码片段和 CodePen 上:

编辑
我在第 8 到 12 行和第 54 行添加了一个 setTimeout“bugfix”。
根据以下评论，setTimeout 可能会在页面刷新 [F5] 时保留在 DOM 中。
为防止出现这种情况，我们会在它存在时将其清除。

var slides = $(".slide");
var lastSlideIndex = slides.length-1;
var currentSlideIndex = 0;
var defaultTiming = 1000;
var defaultFadeInTime = 1000;
var defaultFadeOutTime = 1000;

// Prevents a setTimeout to remain in browser cache on page refresh.
if (typeof slideTimer !== 'undefined') {
  clearTimeout(slideTimer);
}
var slideTimer;

// Show slide function
function showSlide() {
    
	var thisSlide = slides.eq(currentSlideIndex);
	
	// Delays
	var timing = parseFloat(thisSlide.attr("data-timing")) * 1000;	// Transform seconds in milliseconds
	if(isNaN(timing)){timing=defaultTiming; console.log("NOTICE: ----------- data-timing is missing, using default.");}
	var fadeInTime = parseFloat(thisSlide.attr("data-fadein")) * 1000;
	if(isNaN(fadeInTime)){fadeInTime=defaultFadeInTime; console.log("NOTICE: ----------- data-fadein is missing, using default.");}
	var fadeOutTime = parseFloat(thisSlide.attr("data-fadeout")) * 1000;
	if(isNaN(fadeOutTime)){fadeOutTime=defaultFadeOutTime; console.log("NOTICE: ----------- data-fadeout is missing, using default.");}
	
    console.log("Slide: "+currentSlideIndex+":\n Display time: "+timing+" millisec.\n Fadein: "+fadeInTime+" millisec.\n Fadeout: "+fadeOutTime+" millisec.");
    thisSlide.animate({"opacity":1},fadeInTime);
    
	// If this slide contains a video
	if(slides.eq(currentSlideIndex).find("video").length > 0){
		
		// Prevents more than 1 video to play at the same time
		$("video").each(function(){
			console.log("All video paused.")
			$(this)[0].pause();
		});
		
		// Play this video from the start
		var thisVideo = slides.eq(currentSlideIndex).find("video")[0];
		thisVideo.currentTime = 0;
		console.log("Video playing.");
		thisVideo.play()
	}
	
    // Prepare for next slide
    currentSlideIndex++;
	
	// Reset to slide 0 if last was reached
    if(currentSlideIndex>lastSlideIndex){
        currentSlideIndex=0;
    }
    
    slideTimer = setTimeout(function(){
        // Fade out previous slide
		var previousSlideIndex = currentSlideIndex-1;
		
		
		// If previous was last slide
		if(previousSlideIndex == -1){
			previousSlideIndex = lastSlideIndex;
		}
		
		// If previous slide was set to pause
		if(slides.eq(previousSlideIndex).attr("data-videopause")=="true"){
			console.log("Video has been paused.");
			slides.eq(previousSlideIndex).find("video")[0].pause();
		}
		
		slides.eq(previousSlideIndex).animate({"opacity":0},fadeOutTime);
        showSlide();
    }, timing);
}

// Init
showSlide();

img {
    max-width: 78%;
    position:absolute;
    margin-left: 10.5%;
}

video {
    max-width: 78%;
    position:absolute;
    margin-left: 10.5%;
}

.slide{
    opacity:0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="slide" data-timing=4 data-fadein=0.5 data-fadeout=1 data-videopause=false>
    <video>
        <source src="https://www.bessetteweb.com/SO/39920322/video-1.mp4" type="video/mp4">
    </video>
</div>
<div class="slide" data-timing=4 data-fadein=0.5 data-fadeout=0.5><img src="https://upload.wikimedia.org/wikipedia/commons/3/30/Fritz_von_Wille_0071.jpg" /></div>
<div class="slide" data-timing=2 data-fadein=0.5 data-fadeout=1><img src="https://upload.wikimedia.org/wikipedia/commons/f/f3/Truncated_View_of_the_Broekzijdse_Molen_on_the_Gein_by_Piet_Mondrian.jpg" /></div>
<div class="slide" data-timing=6 data-fadein=0.5 data-fadeout=2 data-videopause=true>
    <video>
        <source src="https://www.bessetteweb.com/SO/39920322/video-2.mp4" type="video/mp4">
    </video>
</div>
<div class="slide" data-timing=2 data-fadein=0.5 data-fadeout=3><img src="https://upload.wikimedia.org/wikipedia/commons/0/01/Walter_Leistikow_-_Liebesinsel_(1905).jpg" /></div>
<div class="slide" data-timing=4 data-fadein=0.5 data-fadeout=1><img src="https://upload.wikimedia.org/wikipedia/commons/e/ee/%D0%92%D0%B5%D1%87%D0%B0%D1%80_%D0%90._%D0%93%D0%B0%D1%80%D0%B0%D1%9E%D1%81%D0%BA%D1%96.jpg" /></div>
<div class="slide" data-timing=6 data-fadein=0.5 data-fadeout=0.5 data-videopause=true>
    <video>
        <source src="https://www.bessetteweb.com/SO/39920322/video-3.mp4" type="video/mp4">
    </video>
</div>
<div class="slide" data-timing=3 data-fadein=0.5 data-fadeout=1><img src="https://upload.wikimedia.org/wikipedia/commons/8/88/Morris21.jpg" /></div>
<div class="slide" data-timing=2 data-fadein=0.5 data-fadeout=2><img src="https://upload.wikimedia.org/wikipedia/commons/3/30/Fritz_von_Wille_0071.jpg" /></div>



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