[Learn] Timer class in AS 3.0

It’s been a while since my last post. My connection has been down for a few days, so I haven’t got the chance to post. But during this downtime, I found some time to create some experiments in Flash/AS3.0 (maybe I’ll post it soon). I needed to call a method at timed intervals in this one experiment, and I thought I was in trouble. I never got around to getting how AS2.0 handled timers, if I did manage to do timers, they end up dirty.

AS3.0 has a much much better Timer class to handle just such events. Now, I’m not going to bother comparing the AS3 Timer class with AS2′s timer handling, I’m just going to give a quick intro to the class.

First, you need to create a new Timer object. The constructor has 2 parameters, delay and repeatCount. delay is the time in milliseconds the intervals will be. repeatCount is the number of times the Timer will run, assigning it 0 will set it to run infinitely.

var myTimer:Timer = new Timer(1000, 5);

Now, we want to write a function that will get called when an interval is passed (every 1 second), and when the whole timer finishes counting (after 5 seconds). The Timer class dispatches two events, TimerEvent.TIMER is dispatched when an interval is passed, TimerEvent.TIMER_COMPLETE is dispatched when the timer is finished (I love how simple that is).

stage.addEventListener(TimerEvent.TIMER, everySecond);
stage.addEventListener(TimerEvent.TIMER_COMPLETE, onComplete);

function everySecond(e:TimerEvent):void{
    trace("tick tock!");
}
function onComplete(e:TimerEvent):void{
    trace("Timer finished!");
}

Now, we just need to start the timer. The Timer class has 3 methods, start, stop, and reset. Those are fairly self-explanatory. We could now add the following lines:

myTimer.start();
//modify the onComplete function
function onComplete(e:TimerEvent):void{
    trace("Timer finished!");
    myTimer.reset();
    myTimer.start();
}

So now, when our timer finishes, it will automatically start all over again. This will trace

tick tock!
tick tock!
tick tock!
tick tock!
tick tock!
Timer finished!
tick tock!
tick tock!
...

This was just a really quick intro to the Timer class, I just felt like sharing this because I was so relieved at how easy it was to handle timed events now.