How to get this code to show movieclip correctly? - actionscript-3

Question

I have the following code and it works fine, except I want it to play the Explosion movieclip in the library when an EnemyShip disappears but I only want it to play once and then disappear but not quite sure how to do it (I've tried a few things and it either makes the explosion animation loop and the ships don't disappear, which I believe is as a result of putting it inside the kill function, or I get other ArgumentErrors).
var speed:Number;
var shot = new ShotSound();
var explosion = new Explosion();
this.x = 800;
this.y = Math.random() * 275 + 75;
speed = Math.random()*5 + 9;
addEventListener("enterFrame", enterFrame);
addEventListener(MouseEvent.MOUSE_DOWN, mouseShoot);
function enterFrame(e:Event)
{
this.x -= speed;
if(this.x < -100)
{
removeEventListener("enterFrame", enterFrame);
stage.removeChild(this);
}
}
function kill()
{
stage.addChild(this);
explosion.x = this.x;
explosion.y = this.y;
removeEventListener("enterFrame", enterFrame);
stage.removeChild(this);
shot.play();
}
function mouseShoot(event:MouseEvent)
{
kill();
}
Thank for for any help I may receive.

Answer 1

You need some script to fire when the Explosion reaches it's final frame. A few ways you can do this:
1.
Dispatch an event on the last frame of your explosion animation. eg. this.dispatchEvent(new Event(Event.COMPLETE)); then listen for that event:
var explosion = new Explosion();
addChild(explosion);
explosion.addEventListener(Event.COMPLETE, removeExplosion);
function removeExplosion(e:Event):void {
MovieClip(e.currentTarget).stop();
MovieClip(e.currentTarget).removeEventListener(Event.COMPLETE, removeExplosion);
removeChild(MovieClip(e.currentTarget));
}
2.
Have the explosion remove itself on the last frame of the animation. eg. if(this.parent) parent.removeChild(this);
3.
If you can't or don't want to modify the explosion timeline, use the undocumented AddFrameScript command:
var explosion = new Explosion();
addChild(explosion);
explosion.addFrameScript(explosion.totalFrames-1, function():void {
explosion.stop();
if(explosion.parent){
explosion.parent.removeChild(explosion);
}
});
Here is a tip with your setup:
add a function called removeMe (or similiar) to avoid redundant code (so you call this function on kill or when the ship goes out of bounds
function removeMe(e:Event = null):void {
this.removeEventLIstener(Event.ENTER_FRAME,enterFrame);
if(this.parent){
this.parent.removeChild(this);
}
//any other cleanup that's required
}
Next, an updated kill function:
function kill(){
var explosion = new Explosion();
explosion.addEventListener(Event.COMPLETE, removeMe); //you need to dispatch this event on the last frame of the explosion timeline as shown below
addChild(explosion); //add it to the ship so it stays with it as the ship moves
//not sure what shot.play() does and if that belongs here.
}
//on the last frame of your explosion timeline:
stop();
dispatchEvent(new Event(Event.COMPLETE));

Answer 2

For starters, you're never adding explosion to the display list.
Change
var explosion = new Explosion();
stage.addChild(this);
to
var explosion = new Explosion();
stage.addChild(explosion);
Once you've done that, you'll want to add a listener to explosion to find out when it has finished playing:
explosion.addEventListener(Event.ENTER_FRAME, onExplosionProgress);
function onExplosionProgress(e:Event):void
{
if(explosion.currentFrame == explosion.totalFrames)
{
// explosion has reached end of its timeline
explosion.removeEventListener(Event.ENTER_FRAME, onExplosionProgress);
explosion.stop();
stage.removeChild(explosion);
}
}