A non-nested animation sequence in jQuery?

问题:

I'm trying to create an animation sequence with jQuery where one animation starts after the previous one is done. But I just can't wrap my head around it. I've tried to make use of the jQuery.queue, but I don't think I can use that because it seems to have one individual queue for each element in the jQuery array.

I need something like:

$('li.some').each(function(){
    // Add to queue
    $(this).animate({ width: '+=100' }, 'fast', function(){
        // Remove from queue
        // Start next animation
    });
});

Is there a jQuery way to do this or do I have to write and handle my own queue manually?

回答1:

You can make a custom .queue() to avoid the limitless nesting..

var q = $({});

function animToQueue(theQueue, selector, animationprops) {
    theQueue.queue(function(next) {
        $(selector).animate(animationprops, next);
    });
}

// usage
animToQueue(q, '#first', {width: '+=100'});
animToQueue(q, '#second', {height: '+=100'});
animToQueue(q, '#second', {width: '-=50'});
animToQueue(q, '#first', {height: '-=50'});

Demo at http://jsfiddle.net/gaby/qDbRm/2/

---

If, on the other hand, you want to perform the same animation for a multitude of elements one after the other then you can use their index to .delay() each element's animation for the duration of all the previous ones..

$('li.some').each(function(idx){
    var duration = 500; 
    $(this).delay(duration*idx).animate({ width: '+=100' }, duration);
});

Demo at http://jsfiddle.net/gaby/qDbRm/3/

回答2:

The callback of .animate() actually accepts another .animate(), so all you would have to do would be

    $(this).animate({ width: '+=100' }, 'fast', function(){
         $(selector).animate({attr: val}, 'speed', function(){
});
    });

and so on.

回答3:

You could call the next one recursively.

function animate(item) {
    var elem = $('li.some').eq(item);
    if(elem.length) {
        elem.animate({ width: '+=100' }, 'fast', function() {
            animate(item + 1);
        });
    }
}

animate(0);

回答4:

why not build up a queue?

var interval = 0; //time for each animation
var speed = 200;

$('li.some').each(function(){
    interval++;
    $(this).delay(interval * speed).animate({ width: '+=100' }, speed);
});

EDIT: added speed param

回答5:

Thanks to everybody replying!

I thought I should share the outcome of my question. Here is a simple jQuery slideDownAll plugin that slides down one item at a time rather than all at once.

(function ($) {

    'use strict';

    $.fn.slideDownAll = function (duration, callback) {

        var that = this, size = this.length, animationQueue = $({});

        var addToAnimationQueue = function (element, duration, easing, callback) {
            animationQueue.queue(function (next) {
                $(element).slideDown(duration, easing, function () {
                    if (typeof callback === 'function') {
                        callback.call(this);
                    }
                    next();
                });
            });
        };

        return this.each(function (index) {
            var complete = null,
                easing = 'linear';
            if (index + 1 === size) {
                complete = callback;
                easing = 'swing';
            }
            addToAnimationQueue(this, duration / size, easing, complete);
        });
    };

} (jQuery));

Not very well test, but anyways.

Enjoy!!