Question

I am making a website in Flash, coded in flashbuilder. Whenever I try to export my code I get the same error again and again (TypeError = see below).

I think the problem has something to do with the stage of my project. Whenever I change the var stageMiddenX = (stage.stageWidth / 2); into var stageMiddenX = 512;, the code works. but I wan’t the var to be dynamic.

TypeError
Error #1009: cannot access a property or method of a null object reference at main()

package {
import flash.display.MovieClip;

  public class main extends MovieClip{
    var stageMiddenX = (stage.stageWidth / 2);
    var stageMiddenY = (stage.stageHeight / 2);
    private var object1:Object1 = new Object1();
    private var object2:Object2 = new Object2();
    private var object3:Object3 = new Object3();
  }
}

Answer 1

The issue here is that stage is not yet available at the time you are requesting it.

You’ll want to wait until the Event.ADDED_TO_STAGE event is fired before attempting to acccess stage.

package {
    import flash.display.MovieClip;

    public class main extends MovieClip{
        private var object1:Object1 = new Object1();
        private var object2:Object2 = new Object2();
        private var object3:Object3 = new Object3();
        private var stageMiddenX:Number;
        private var stageMiddenY:Number;

        public function main(){
            if(stage) init(null);
            else addEventListener(Event.ADDED_TO_STAGE, init)
        }

        private function init(e:Event):void {
            removeEventListener(Event.ADDED_TO_STAGE, init);
            stageMiddenX = (stage.stageWidth / 2);
            stageMiddenY = (stage.stageHeight / 2);
        }
    }
}