Set timer with random interval - actionscript-3

Question

I have the current code:
enemyShipTimer = new Timer(2000);
enemyShipTimer.addEventListener("timer", sendEnemy);
enemyShipTimer.start();
How do I change the timer so that instead of triggering sendEnemy every 2 seconds, it triggers it at a random time between 1 and 3 seconds?

Answer 1

The Timer class possess the delay property which indicates the delay between two "timer" events. So, you just have to randomly change the delay (for the next spawn) at the beginning of sendEnemy.
function sendEnemy(evt:TimerEvent):void {
Timer(evt.currentTarget).delay = (1+Math.random()*2)*1000; // change the delay until the next call.
// continue with the usual sendEnemy code.
}

Answer 2

Triggering between 1 and 3 seconds, means that each second it has 33% chance to be triggered. So:
enemyShipTimer = new Timer( 1000 );
enemyShipTimer.addEventListener("timer", function( e:TimerEvent ):void
{
if( Math.random() < 0.33 )
{
trace( "triggered!" );
}
});
enemyShipTimer.start();

Answer 3

package
{
import flash.display.MovieClip;
import flash.events.Event;
import flash.utils.Timer;
import flash.events.TimerEvent;
public class Test extends MovieClip {
private var _timer:Timer = null;
public function Test() : void {
addEventListener(Event.ADDED_TO_STAGE, _Init);
}
private function _Init(e:Event) : void {
_RandomTimer();
}
private function _RandomCount() : Number {
var min = 1000;
var max = 2000;
return Math.floor(Math.random() * max + min);
}
private function _RandomTimer() : void {
_timer = new Timer(_RandomCount(), 1);
_timer.addEventListener(TimerEvent.TIMER, _OnTimerCall);
_timer.addEventListener(TimerEvent.TIMER_COMPLETE, _OnTimerEnd);
_timer.start();
}
private function _OnTimerCall(e:TimerEvent) : void {
trace(_timer.delay);
}
private function _OnTimerEnd(e:TimerEvent) : void {
_timer.removeEventListener(TimerEvent.TIMER_COMPLETE, _OnTimerEnd);
_RandomTimer();
}
}
}

Answer 4

You can use the Math.random function.
You can choose the maximum value of the random function by multiplying it.
But your random would still go to zero, so you have to add it with a starting number.
var randomNumber:Number = Math.random(); // Number between 0 - 1
randomNumber *= 2000; // Number between 0 - 2000
randomNumber += 1000; // Number between 1000 - 3000
enemyShipTimer = new Timer(randomNumber);
enemyShipTimer.addEventListener("timer", sendEnemy);
enemyShipTimer.start();