Error

1

Hey Guys,

I just started trying to learn AS3 and I am getting an error that I can’t seem to fix or work around.

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at code::Character()
at code::Engine()

I think it is because of the:

stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, keyReleaseHandler);

But I am not sure how else to grab key presses in AS3

Here is my code:

Engine.as

package code {
	
	import flash.display.MovieClip;
	import flash.display.Stage;
	
	public class Engine extends MovieClip {
		
		
		public function Engine() {
			// constructor code
			
			//Creating object of the character from the Character Class
			var ourChar:Character = new Character();
			
			//Adding the character to the stage
			stage.addChild(ourChar);
			
			//Setting the characters position
			ourChar.y = stage.stageHeight / 2;
			ourChar.x = stage.stageWidth / 2;
			
		}
		
	}
	
}

Character.as

package code {
	
	import flash.display.MovieClip;
	import flash.display.Stage;
	import flash.events.Event;
	import flash.events.KeyboardEvent;
	import flash.ui.Keyboard;
	
	public class Character extends MovieClip {
		
		//Setting Movement Buttons
		private var w:Boolean = false;
		private var a:Boolean = false;
		private var s:Boolean = false;
		private var d:Boolean = false;
		
		//Setting Movement Variables
		private var speed:Number = 10;
		
		//Detecting Degree of mouse depending on tank position
		private var am:Number = mouseY - y;
		private var bm:Number = mouseX - x;
		private var radiansm:Number = Math.atan2(am, bm);
		private var degreesm:Number = radiansm / (Math.PI / 180);
		
		public function Character() {
			// constructor code
			
			addEventListener(Event.ENTER_FRAME,enterFrameHandler);
			stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressHandler);
			stage.addEventListener(KeyboardEvent.KEY_UP, keyReleaseHandler);
		}
		
		
		public function enterFrameHandler(event:Event) {
			if (a && !d){
				this.x -= speed ;
			}
			
			if (d && !a){
				this.x += speed ;
			}
			
			if (w && !s){
				this.y -= speed;
			}
			
			if (s && !w){
				this.y += speed;
			}
		}
		
		public function keyPressHandler(event:KeyboardEvent):void{
			
			//A = 65
			//D = 68
			//S = 83
			//W = 87
			
			switch(event.keyCode){
				case 87:
					w = true;
					break;
				
				case 65:
					a = true;
					break;
				
				case 83:
					s = true;
					break;
				
				case 68:
					d = true;
					break;
			}
		}	
		
		public function keyReleaseHandler(event:KeyboardEvent):void{
			switch(event.keyCode){
				case 87:
					w = false;
					break;
				
				case 65:
					a = false;
					break;
				
				case 83:
					s = false;
					break;
				
				case 68:
					d = false;
					break;
			}
		}
	}
}

Any help would be great!

Thanks!