?From：http://blog.csdn.net/dante_k7/archive/2009/06/18/4275381.aspx
FLEX组件在建立的时候都会经历四个事件：preinitialize,initialize,creationComplete 和 updateComplete（updateComplete事件在任何改动视觉的情况下都会发生，不是初始化时独有的）。
下面的例子检测在嵌套和平行的情况下，各个组件的事件抛出顺序。
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"
??????????????????????????????? preinitialize="showEvent(event)"
??????????????????????????????? initialize="showEvent(event)"
??????????????????????????????? creationComplete="showEvent(event)"
??????????????????????????????? updateComplete="showEvent(event)">
???????
??????? <mx:script>
??????????????? <!--[CDATA[
??????????????? import flash.utils.getTimer;
??????????????? private function showEvent(event:Event):void {
??????????????? trace(flash.utils.getTimer().toString()+" >> "+event.currentTarget.name+" "+event.type);
??????????????? }
??????????????? ]]-->
??????? </mx:script>
???????
??????? <mx:Canvas id="canv1"
?????????????????????????? preinitialize="showEvent(event)"
?????????????????????????? initialize="showEvent(event)"
?????????????????????????? creationComplete="showEvent(event)"
?????????????????????????? updateComplete="showEvent(event)">
???????????????
??????????????? <mx:Button id="btn1"
?????????????????????????????????? preinitialize="showEvent(event)"
?????????????????????????????????? initialize="showEvent(event)"
?????????????????????????????????? creationComplete="showEvent(event)"
?????????????????????????????????? updateComplete="showEvent(event)"/>
??????? </mx:Canvas>
???????
??????? <mx:Button id="btn2"
?????????????????????????? preinitialize="showEvent(event)"
?????????????????????????? initialize="showEvent(event)"
?????????????????????????? creationComplete="showEvent(event)"
?????????????????????????? updateComplete="showEvent(event)"/>
???????
</mx:Application>
上面的例子输出顺序是：
1299 >> eventTest0 preinitialize
1307 >> canv1 preinitialize
1310 >> btn1 preinitialize
1318 >> btn1 initialize
1319 >> canv1 initialize
1320 >> btn2 preinitialize
1321 >> btn2 initialize
1321 >> eventTest0 initialize
[SWF] G:projectseventTestbin-debugeventTest.swf - 588,818 bytes after decompression
1387 >> btn1 creationComplete
1387 >> btn1 updateComplete
1387 >> canv1 creationComplete
1387 >> canv1 updateComplete
1388 >> btn2 creationComplete
1388 >> btn2 updateComplete
1388 >> eventTest0 creationComplete
1390 >> eventTest0 updateComplete
看着有点混乱，不过仔细看看，可以把过程分成两个部分。
很明显，所有的creationComplete和updateComplete发生在第二次update的时候，之前flex组件只是做一些设置和计算的工作，并没有在画布上画任何东西。除此之外，还有这么一些规律： ? ? * 就单个组件而言，事件的抛出顺序是preinitialize，initialize，creationComplete ? ? * 嵌套关系的两个组件（比如Canvas和button1），preinitialize先外后内，initialize和creationComplete先内后外。只是creationComplete要在下一次update才会发生。 ? ? * 平行关系的两个组件（比如Canvas和button2），按mxml内的顺序，只有前面组件initialize结束后，后面的组件才会抛出preinitialize。
