MACROMEDIA FLEX 2-MIGRATING APPLICATIONS TO FLEX 2 Manuel d'utilisateur télécharger pdf (Page 182)

182 Migration Patterns

Using Timer

The setInterval() and clearInterval() methods were deprecated in favor of the Timer

class. You can still use these methods; they are in the flash.util package.

When you use Timers, keep the following in mind:

■ When a Timer is first created with the new operator, it is stopped; you must use the

start() method to start it.

■ Instances of the Timer class dispatch events that you handle like any other event.

The following example creates and destroys a Timer object each time you click the Start and

Stop buttons. Setting the timer to

null allows it to be garbage collected.

<?xml version="1.0"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

<mx:Script><![CDATA[

import flash.util.Timer;

import flash.events.TimerEvent;

private var timer:Timer;

private function startTimer():void {

timer = new Timer(1000);

timer.addEventListener(TimerEvent.TIMER, timerHandler);

timer.start();

}

private function stopTimer():void {

timer.stop();

timer = null;

}

private function timerHandler(event:TimerEvent):void {

trace("timer");

}

]]></mx:Script>

<mx:Button label="Start Timer" click="startTimer();"/>

<mx:Button label="Stop Timer" click="stopTimer();"/>

</mx:Application>

You can also use the reset() method rather than the stop() method to stop the timer. The

difference between

stop() and reset() is that stop() stops the timer but does not reset its

count, while

reset() both stops and resets.

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MACROMEDIA FLEX 2-MIGRATING APPLICATIONS TO FLEX 2 Manuel d'utilisateur Page 182