Question

This is a little snippet from a little flash game I’m working on:

This bit from my GamePlayScreen class:

public function handleKeyboard(e:KeyboardEvent):void {
        if(e.type == KeyboardEvent.KEY_DOWN && e.keyCode == Keyboard.ENTER) {
            var enemy:EnemyShip = new EnemyShip();
            enemyships.push(enemy);
            addChild(enemyships[enemyships.length-1]);
        }
    }

and this bit is causing the error (I marked the line with *)

for each (var enemy:EnemyShip in Game.gameplay.enemyships) {
            if(this.hitTestObject(enemy)) {
                *enemy.parent.removeChild(enemy);
            }

gameplay is an instance of GamePlayScreen declared in my document class Game. I already traced enemy.parent and it told me it was [Object GamePlayScreen], yet the error tells me it is null?

This is the error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Laser1/moveUp()[C:\Dev\Projects\Gamedev\Flash\classes\Laser1.as:23]

I tryed everything, tracing on every line, and still no results… Even when I use

if(Game.gameplay.contains(enemy) {
    enemy.parent.removeChild(enemy);
}

it continues to stumble on this error again…
I am clueless…

Answer 1

A simple solution may be checking if the value is not null and the enemy still has a parent.

for each (var enemy:EnemyShip in Game.gameplay.enemyships) {
  if(enemy && enemy.parent && this.hitTestObject(enemy)) {
    enemy.parent.removeChild(enemy);
  }
}