Flash AS3 - Timer goes crazy after a few loops - actionscript-3

Question

I've been making a "slideshow" where 4 images are animated in random order.
To prevent multiple animations to one image for example 3 times successively, I've write a little logic.
My problem : after a few times all the 4 images are animated (after the query 'array' is cleared the second time I think), the timer goes crazy and trace() random numbers in a high sequence rate without to animate the images, with would look creepy I think.
My code :
var myTimer:Timer = new Timer(2500);
myTimer.addEventListener(TimerEvent.TIMER, animate);
myTimer.start();
var array:Array = new Array();
var lastNum:int;
function animate(e:TimerEvent):void {
var num:int = getRandomNumber( 1, 4 );
trace( num );
if( array.indexOf( num ) < 0 && num != lastNum ) {
myTimer.delay = 2500;
if( num == 1 ) {
sideImg_start_1.play(); // comment this*
} else if( num == 2 ) {
sideImg_start_2.play(); // comment this*
} else if( num == 3 ) {
sideImg_start_3.play(); // comment this*
} else if( num == 4 ) {
sideImg_start_4.play(); // comment this*
}
array.push( num );
if( array.length == 4 ) {
array.splice(0, 4);
trace(" array cleared - " + array.length);
lastNum = num;
}
} else {
myTimer.delay = 100; // I've also tryed so make a higher delay
// like 500 but its the same problem...
}
}
function getRandomNumber( min:int, max:int ):int {
return Math.floor( Math.random() * ( 1 + max - min ) ) + min;
}
stop();
So guys, thanks for all your answers and your help :D
UPDATE:
First I've tried to simply call the 'animate()' function instead of defining a higher speed to the timer to call the next number fast, without to loose time, which would make the random animation look weird.
I've used animate(null); instead of myTimer.delay = 100; before, but then I was getting a STACKOVERFLOW error :P

Answer 1

For example if your lastNum is equal to 4, and you have 1,2 and 3 as new values, than you will end up with an infinite loop,
because you can't insert 4 (because it's equal to the lastNum) and you can't insert 1,2 or 3 because they are already in the array.
What you need to do is:
if (array.length == 4) {
array.splice(0, 4);
lastNum = num;
} else {
lastNum = 0; //<-- HERE
}