Timer的妙用

<?xml version="1.0" encoding="utf-8"?>
<mx:Application name="Alert_PopUpManager_removePopUp_test"
				xmlns:mx="http://www.adobe.com/2006/mxml"
				backgroundColor="white"
				initialize="init();">
	
	<mx:Script>
		<![CDATA[
			import mx.controls.Alert;
			import mx.events.CloseEvent;
			import mx.managers.PopUpManager;
			
			private var alrt:Alert;
			private var alrtTimer:Timer;
			
			private function init():void {
				alrtTimer = new Timer(3000, 1);
				alrtTimer.addEventListener(TimerEvent.TIMER_COMPLETE, removeAlert);
			}
			
			private function showAlert():void {
				alrt = Alert.show("I'm an Alert control and I will close in 5 seconds unless closed by a user.", "Self closing Alert", Alert.OK, this, alrt_close);
				alrtTimer.reset();
				alrtTimer.start();
			}
			
			private function alrt_close(evt:CloseEvent):void {
				alrtTimer.stop();
				lbl.text = "Closed by user.";
			}
			
			private function removeAlert(evt:TimerEvent):void {
				PopUpManager.removePopUp(alrt);
				lbl.text = "Removed by application.";
			}
		]]>
	</mx:Script>
	
	<mx:Button label="Show Alert" click="showAlert();" />
	<mx:Label id="lbl" />
	
</mx:Application>

setTimeout()