jQuery cross fading two images on a loop!

问题

I am having trouble working out how to get a simple fade in fade out loop to work. I am pretty new to jQuery as you can maybe tell. I have had a go at it but now it’s taking too long to work out so I thought I would ask for some help.

What I want to do:

I have two Images, id's #img1 and #img2. I want image 1 to fadeIn then wait for lets say 6 seconds then fade out. I have tried the .wait function but it just stopped the little I had from working. I managed to get the first image to fade in and then out but with no wait in between. I then want to start fading image 2 in while image 1 is fading out then Image 2 to wait then fade out while image 1 fades in again and loop forever! Hope that makes sense.

 $(document).ready(function(){
  $('#img1').hide()
.load(function () {
  $(this).fadeIn(4500)
  .fadeOut(4500);
  $('#img2').hide().wait(9000)
  .load(function () {
  $(this).fadeIn(4500)
  .fadeOut(4500);
});

Cheers, its driving me crazy. Ps can you try and give a little explanation to what is going on in you answer. Thanks

回答1:

Edit 2+ years later: There are better ways to do this... so ignore this answer.

---

I would try a combination of callbacks and setTimeout. (I'm going to build on Kobi's response, since he posted while I was typing.)

In CSS, give both images a "display: none;" instead of setting them to hidden at the beginning in jQuery. Then in jQuery:

function imageOneFade(){
  $('#img1').fadeIn(2000, function(){ setTimeout("$('#img1').fadeOut(2000); imageTwoFade();",6000); });
}

function imageTwoFade(){
  $('#img2').fadeIn(2000, function(){ setTimeout("$('#img2').fadeOut(2000); imageOneFade();",6000); });
}

$(document).ready(function(){
   imageOneFade();
});

Hopefully something like that you work.

The setTimeout function takes two parameters.

setTimeout(WHAT WILL HAPPEN, HOW LONG TO WAIT)

And the fadeIn/Out functions can have a second parameter that will trigger when the effect is finished.

回答2:

Here's a four image looping slideshow that does not use the setTimeout function, but instead uses the delay function.

<script>
  function startSlideshow(){
    $("div.text_b1").fadeIn(1000).delay(10500).fadeOut(1500); //13000
    $("div.text_b2").delay(13000).fadeIn(1500).delay(11000).fadeOut(1500); //27000
    $("div.text_b3").delay(27000).fadeIn(1500).delay(11000).fadeOut(1500); //41000
    $("div.text_b4").delay(41000).fadeIn(1500).delay(11000).fadeOut(1500, startSlideshow); //55000
  }

  $(document).ready(function(){
    startSlideshow();
  });
</script>

see it in action http://www.erestaurantwebsites.com/

回答3:

Why don't you use a solution already made like the Cycle plugin?

It has a lot more of options than you want to do.

If you really need to do this by yourself you could watch at the source code of the plugin. I didn't do that, but I think the coder uses a combination of the animate function (from jQuery) and the setTimeout function (from purely javascript). Using those functions he must do something like to enable a timer for an amount of time, and when time's complete he execute the animate function setting the opacity of the image to 0 (for the image hidding) and 1 (for the image showing).

回答4:

You can use a combination of jQuery's callbacks and JavaScript setTimeout.
setTimeout is used for delays, and callbacks are used after animations complete (there are many other callbacks though).

function startSlideshow(){
  $('#p1').fadeOut(2000, function(){
    setTimeout(function(){
      $('#p1').fadeIn(2000, startSlideshow)
    },1000);
  });
}

$(document).ready(function(){
   startSlideshow();
});

See it in action: http://jsbin.com/ulugo

回答5:

Based on delay() function, here is the solution for number of images, if loop of images in bigger numbers needed. This gives a B->A crossfade effect (or remove the +fadems/2 for simple fadeOutIn effect). Mind - images must be in position: absolute !important; (see html example).

jQuery:

function startSlideshow(){

    var dms = 2500; // image show duration in ms
    var fadems = 750; // crossfade in ms
    var imgnum = 5; // total number of images
    var nms = 0;

    // fadeInOut first image
    $("#img1").fadeIn(fadems).delay(dms).fadeOut(fadems);  
    nms = nms + fadems*2 + dms- fadems/2;   

    // fadeInOut rest images
    for (var i = 2; i<imgnum; i++){
        // remove +fadems/2 for fadeOut effect, instead of crossfade
        $("#img"+i).delay(nms).fadeIn(fadems).delay(dms).fadeOut(fadems+fadems/2); 
        nms = nms + fadems*2 + dms - fadems/2;  
    }
    // fadeInOut last image and start over
        $("#img"+imgnum).delay(nms).fadeIn(fadems).delay(dms).fadeOut(fadems, startSlideshow);
}

startSlideshow();

HTML: note: next image id is rised by ++ : #img1, #img2, #img3.... #img128 etc.

<style>
    .crossfade {
        /* image width and height */
        width: 160px;
        height: 120px;
        display: none; 
        position: absolute !important;

    }
</style>

<div class="place_your_images_container_where_is_needed">

    <div id="img1" class = "crossfade" >
        <img src="imageOne.png" />
    </div>

    <div id="img2" class = "crossfade" >
        <img src="image2.png" />
    </div>

    <div id="img3" class = "crossfade" >
        <img src="image3.png" />
    </div>

    <div id="img4" class = "crossfade" >
        <img src="imageFour.png" />
    </div>

    <div id="img5" class = "crossfade" >
        <img src="imageLast.png" />
    </div>

</div>

p.s. use transparent PNG images for better effect.

回答6:

This is how I would do it with simple jQuery. See working snippet.

loopStart();

function loopStart() {
  $("#image1").delay(2000).fadeOut("slow", function() {
    loopTwo();
  });
};

function loopOne() {
  $("#image1").fadeIn("slow", function() {
    $("#image1").delay(2000).fadeOut("slow", function() {
      loopTwo();
    });
  });
};

function loopTwo() {
  $("#image2").fadeIn("slow", function() {
    $("#image2").delay(2000).fadeOut("slow", function() {
      loopOne();
    });
  });
};

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<img id="image1" src="http://lorempixel.com/city/200/200">
<img id="image2" style="display:none;" src="http://lorempixel.com/people/200/200">

来源：https://stackoverflow.com/questions/1386374/jquery-cross-fading-two-images-on-a-loop