Flex之旅：第二部分：容器与布局(1)---容器的初始化顺序

容器的初始化顺序



如下代码：

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
			   xmlns:s="library://ns.adobe.com/flex/spark"
			   xmlns:mx="library://ns.adobe.com/flex/mx"
			   minWidth="955" minHeight="600">
	<fx:Script>
		<![CDATA[
			import mx.events.FlexEvent;
			
			protected function hgroup1_preinitializeHandler(event:FlexEvent):void
			{
				trace("hgroup1_preinitializeHandler");	
			}
			
			protected function vgroup1_preinitializeHandler(event:FlexEvent):void
			{
				trace("vgroup1_preinitializeHandler");
			}
			
			protected function panel1_preinitializeHandler(event:FlexEvent):void
			{
				trace("panel1_preinitializeHandler");
			}
			
			protected function hgroup1_initializeHandler(event:FlexEvent):void
			{
				trace("hgroup1_initializeHandler");
			}
			
			protected function vgroup1_initializeHandler(event:FlexEvent):void
			{
				trace("vgroup1_initializeHandler");
				
			}
			
			protected function panel1_initializeHandler(event:FlexEvent):void
			{
				trace("panel1_initializeHandler");
			}
			
			protected function hgroup1_creationCompleteHandler(event:FlexEvent):void
			{
				trace("hgroup1_creationCompleteHandler");
			}
			
			protected function vgroup1_creationCompleteHandler(event:FlexEvent):void
			{
				trace("vgroup1_creationCompleteHandler");
			}
			
			protected function panel1_creationCompleteHandler(event:FlexEvent):void
			{
				trace("panel1_creationCompleteHandler");
			}
			
		]]>
	</fx:Script>

	
	
	<s:HGroup creationComplete="hgroup1_creationCompleteHandler(event)"
			  initialize="hgroup1_initializeHandler(event)"
			  preinitialize="hgroup1_preinitializeHandler(event)">
		<s:VGroup creationComplete="vgroup1_creationCompleteHandler(event)"
				  initialize="vgroup1_initializeHandler(event)"
				  preinitialize="vgroup1_preinitializeHandler(event)">
			<s:Panel creationComplete="panel1_creationCompleteHandler(event)"
					 initialize="panel1_initializeHandler(event)"
					 preinitialize="panel1_preinitializeHandler(event)">
			</s:Panel>
		</s:VGroup>
	</s:HGroup>
</s:Application>

console:

hgroup1_preinitializeHandler

vgroup1_preinitializeHandler

panel1_preinitializeHandler

panel1_initializeHandler

vgroup1_initializeHandler

hgroup1_initializeHandler

panel1_creationCompleteHandler

vgroup1_creationCompleteHandler

hgroup1_creationCompleteHandler

几点说明：

如上代码里：HGroup 包裹 VGroup 包裹 Panel

初始化顺序是：先preinitialize，再initialize，最后creationComplete

preinitialize顺序(从外到内)： HGroup->VGroup ->Panel

initialize顺序(从内到外)：Panel->VGroup ->HGroup

creationComplete顺序（从内到外）：Panel->VGroup ->HGroup

当组件广播preinitialize 和initialize 事件时，它的子组件还没有创建完成。因此，要访问某个组件的所有子组件，必须侦听creationComplete 时间。在广播initialize 事件后，组件本身已经完成测量、绘制和布局，但是其子组件可能仍未完全完成实例化过程。最后，creationComplete 事件表明所有容器内的子组件都完全实例化结束。