UIComponent的生命周期(life cycle)

写flex组件,了解UIComponent的生命周期(life cycle)很重要,尤其是初始化(initialization)的过程很复杂,贴个文件可以很容易看清这个顺序

文件如下:

package
{
  import flash.events.Event;
  
  import mx.core.UIComponent;
  import mx.events.FlexEvent;
 
  public class UILifeCycle extends UIComponent
  {
    public function UILifeCycle()
    {
   super();
     trace("***[ constructor ]");
      
     //flash.events.Event
     this.addEventListener(Event.ADDED,onAdded);
     this.addEventListener(Event.ADDED_TO_STAGE,onAddedToStage);
     this.addEventListener(Event.REMOVED,onRemoved);
     this.addEventListener(Event.REMOVED_FROM_STAGE,onRemovedFromStage);
    
     //mx.events.FlexEvent;
     this.addEventListener(FlexEvent.ADD,onAdd);
     this.addEventListener(FlexEvent.REMOVE,onRemove);
     this.addEventListener(FlexEvent.PREINITIALIZE,onPreinitialize);
     this.addEventListener(FlexEvent.INITIALIZE,onInitialize);
     this.addEventListener(FlexEvent.CREATION_COMPLETE,onCreationComplete);
    
    }
    
    //flash.events.Event
    private function onAdded(eo:Event):void{trace(eo.toString())};
    private function onAddedToStage(eo:Event):void{trace(eo.toString())};
    private function onRemoved(eo:Event):void {trace(eo.toString())};
    private function onRemovedFromStage(eo:Event):void {trace(eo.toString())};
    
    //mx.events.FlexEvent;
    private function onAdd(eo:FlexEvent):void {trace(eo.toString())};
    private function onRemove(eo:FlexEvent):void{trace(eo.toString())};
    private function onPreinitialize(eo:FlexEvent):void{trace(eo.toString())};
    private function onInitialize(eo:FlexEvent):void{trace(eo.toString())};
 private function onCreationComplete(eo:FlexEvent):void{trace(eo.toString())};  
 
   override protected function createChildren():void{trace("***[ createChildren ]")}
   override protected function commitProperties():void{trace("***[ commitProperties ]")}
   override protected function measure():void{trace("***[ measure ]")}  
   override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void{trace("***[ updateDisplayList]")}
  
  }
}

拖到舞台上发布就可以看到trace信息了

***[ constructor ]
[Event type="added" bubbles=true cancelable=false eventPhase=2]
[Event type="add" bubbles=false cancelable=false eventPhase=2]
[Event type="preinitialize" bubbles=false cancelable=false eventPhase=2]
***[ createChildren ]
[Event type="initialize" bubbles=false cancelable=false eventPhase=2]
***[ commitProperties ]
***[ measure ]
***[ updateDisplayList]
[Event type="creationComplete" bubbles=false cancelable=false eventPhase=2]
[Event type="addedToStage" bubbles=false cancelable=false eventPhase=2]

如果想详细的了解各个部分请看本站推荐过的 <Programing Flex 2>那本书的最后一章

或者在自带的帮助中找 Creating and Extending Flex 3 Components / Creating ActionScript Components / Creating Advanced Visual Components in ActionScript

偶简单总结了一下

组件的life cycle包含3个阶段:initialization, update, destruction.

initialization阶段又包括construction部分, attachment部分,和initialization部分,直接看偶下边画的图吧

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