还有一个答案，希望是我的最后一个......
不幸的是，John Resig 的 syncAnimate 方法无法满足我想要制作的手风琴式动画效果。虽然它在 Firefox 上运行良好，但我无法让它在 IE 或 Safari 上顺利运行。
话虽如此，我决定硬着头皮编写自己的动画引擎来执行简单的并行动画。类代码使用 jquery 函数，但不是 jquery 插件。另外，我只将它设置为做大小/位置动画，这就是我所需要的。
ParallelAnimations = function(animations, opts){
this.init(animations, opts);
};
$.extend(ParallelAnimations.prototype, {
options: {
duration: 250
},
rules: {},
init: function(animations, opts){
// Overwrite the default options
$.extend(this.options, opts);
// Create a set of rules to follow in our animation
for(var i in animations){
this.rules[i] = {
element: animations[i].element,
changes: new Array()
};
for(var style in animations[i].styles){
// Calculate the start and end point values for the given style change
var from = this.parse_style_value(animations[i].element, style, "");
var to = this.parse_style_value(animations[i].element, style, animations[i].styles[style]);
this.rules[i].changes.push({
from: from,
to: to,
style: style
});
}
}
this.start()
},
/*
* Does some parsing of the given and real style values
* Allows for pixel and percentage-based animations
*/
parse_style_value: function(element, style, given_value){
var real_value = element.css(style);
if(given_value.indexOf("px") != -1){
return {
amount: given_value.substring(0, (given_value.length - 2)),
unit: "px"
};
}
if(real_value == "auto"){
return {
amount: 0,
unit: "px"
};
}
if(given_value.indexOf("%") != -1){
var fraction = given_value.substring(0, given_value.length - 1) / 100;
return {
amount: (real_value.substring(0, real_value.length - 2) * fraction),
unit: "px"
};
}
if(!given_value){
return {
amount: real_value.substring(0, real_value.length - 2),
unit: "px"
};
}
},
/*
* Start the animation
*/
start: function(){
var self = this;
var start_time = new Date().getTime();
var freq = (1 / this.options.duration);
var interval = setInterval(function(){
var elapsed_time = new Date().getTime() - start_time;
if(elapsed_time < self.options.duration){
var f = elapsed_time * freq;
for(var i in self.rules){
for(var j in self.rules[i].changes){
self.step(self.rules[i].element, self.rules[i].changes[j], f);
}
}
}
else{
clearInterval(interval);
for(var i in self.rules){
for(var j in self.rules[i].changes)
self.step(self.rules[i].element, self.rules[i].changes[j], 1);
}
}
}, 10);
},
/*
* Perform an animation step
* Only works with position-based animations
*/
step: function(element, change, fraction){
var new_value;
switch(change.style){
case 'height':
case 'width':
case 'top':
case 'bottom':
case 'left':
case 'right':
case 'marginTop':
case 'marginBottom':
case 'marginLeft':
case 'marginRight':
new_value = Math.round(change.from.amount - (fraction * (change.from.amount - change.to.amount))) + change.to.unit;
break;
}
if(new_value)
element.css(change.style, new_value);
}
});
那么只需在 animate 方法中修改原有的 Accordion 类即可使用新的调用。
Accordion = function(container_id, options){
this.init(container_id, options);
}
$.extend(Accordion.prototype, {
container_id: '',
options: {},
active_tab: 0,
animating: false,
button_position: 'below',
duration: 250,
height: 100,
handle_class: ".handle",
section_class: ".section",
init: function(container_id, options){
var self = this;
this.container_id = container_id;
this.button_position = this.get_button_position();
// The height of each section, use the height specified in the stylesheet if possible
this.height = $(this.container_id + " " + this.section_class).css("height");
if(options && options.duration) this.duration = options.duration;
if(options && options.active_tab) this.active_tab = options.active_tab;
// Set the first section to have a height and be "open"
// All the rest of the sections should have 0px height
$(this.container_id).children(this.section_class).eq(this.active_tab)
.addClass("open")
.css("height", this.height)
.siblings(this.section_class)
.css("height", "0px");
// figure out the state of the handles
this.do_handle_logic($(this.container_id).children(this.handle_class).eq(this.active_tab));
// Set up an event handler to animate each section
$(this.container_id + " " + this.handle_class).mouseover(function(){
if(self.animating)
return;
self.animate($(this));
});
},
/*
* Determines whether handles are above or below their associated section
*/
get_button_position: function(){
return ($(this.container_id).children(":first").hasClass(this.handle_class) ? 'above' : 'below');
},
/*
* Animate the accordion from one node to another
*/
animate: function(handle){
var active_section = (this.button_position == 'below' ? handle.prev() : handle.next());
var open_section = handle.siblings().andSelf().filter(".open");
if(active_section.hasClass("open"))
return;
this.animating = true;
// figure out the state of the handles
this.do_handle_logic(handle);
// Close the open section
var arr = new Array();
arr.push({
element: open_section,
styles: {
"height": "0px"
}
});
arr.push({
element: active_section,
styles: {
"height": this.height
}
});
new ParallelAnimations(arr, {duration: this.duration});
var self = this;
window.setTimeout(function(){
open_section.removeClass("open");
active_section.addClass("open");
self.animating = false;
}, this.duration);
},
/*
* Update the current class or "state" of each handle
*/
do_handle_logic: function(handle){
var all_handles = handle.siblings(".handle").andSelf();
var above_handles = handle.prevAll(this.handle_class);
var below_handles = handle.nextAll(this.handle_class);
// Remove all obsolete handles
all_handles
.removeClass("handle_on_above")
.removeClass("handle_on_below")
.removeClass("handle_off_below")
.removeClass("handle_off_above");
// Apply the "on" state to the current handle
if(this.button_position == 'below'){
handle
.addClass("handle_on_below");
}
else{
handle
.addClass("handle_on_above");
}
// Apply the off above/below state to the rest of the handles
above_handles
.addClass("handle_off_above");
below_handles
.addClass("handle_off_below");
}
});
HTML 仍然以同样的方式调用：
<html>
<head>
<title>Parallel Accordion Animation</title>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="ui.js"></script>
<script type="text/javascript">
$(document).ready(function(){
new Accordion("#accordion");
});
</script>
<style type="text/css">
#accordion{
position: relative;
}
#accordion .handle{
width: 260px;
height: 30px;
background-color: orange;
}
#accordion .section{
width: 260px;
height: 445px;
background-color: #a9a9a9;
overflow: hidden;
position: relative;
}
</style>
</head>
<body>
<div id="accordion">
<div class="section"><!-- --></div>
<div class="handle">handle 1</div>
<div class="section"><!-- --></div>
<div class="handle">handle 2</div>
<div class="section"><!-- --></div>
<div class="handle">handle 3</div>
<div class="section"><!-- --></div>
<div class="handle">handle 4</div>
<div class="section"><!-- --></div>
<div class="handle">handle 5</div>
</div>
</body>
</html>
我以后可能会添加一些内容：
- 排队动画
- 其他类型样式（颜色等）的动画