CODEWITHSUNDEEP
actionscript-3
ILearn
ILearn

Reputation: 11

How to reference objects in AS3?

I've learned one way to do that, but I want to improve my knowledge. For simplicity I'm not going to use import neither extends in the code below.

1

public class Main
{
public function Main()
{
new MyCustomObject(stage);
}
}

2

public class MyCustomObject
{
public var referenceStage:Stage = new Stage();

public function MyCustomObject(xxx:Stage)
{
 this.referenceStage = xxx;
 referenceStage.addChild(this);
}
}

I've learned it reading a tutorial over internet, but I want to know where I can find more samples on how to reference objects in AS3. For future codes, I want to add hitTest and the like.

Thanks !

Upvotes: 1

Views: 3061

Answers (3)

Yves
Yves

Reputation: 172

In your example, you don't need do call new Stage() in your CustomObject 

public var referenceStage:Stage;

is enough

A hitting function may be found here http://troygilbert.com/2007/06/pixel-perfect-collision-detection-in-actionscript3/

Possible solutions are:

  • Instead of passing the stage object, you can also pass the main object and calling functions in the main object for the custom object
  • Maintain an array in the MainObject with which you want do collisions test.
  • Implementing an Interface (extend an object) with a function which do the hit test agains the array in the MainObject (for example went the EntreFrame Event is fired)
  • Custom Events are the solution for communicating with the main object loosely

Passing a reference to an object in the constructor is a classic OOP pattern

Upvotes: 0

momo
momo

Reputation: 3935

if you absolutely want to pass a stage reference through an argument to a constructor, you can do so about how you have it laid out (although get rid of the new Stage() call, which won't do anything).

that said, .stage is a property available to all display objects that are in the display list (meaning: the have been added via addChild or addChildAt).

you're probably getting that error trying to reference a .stage property of an object before it's been added to the display list. this is a common error, and can be handled by waiting to reference the .stage property until it has been added, usually using addEventListener(Event.ADDED_TO_STAGE...

so instead of 

public class MyObject extends Sprite {
  public function MyObject():void{
    this.x = this.stage.stageWidth/2;
  }
}

you'd use something like this

public class MyObject extends Sprite {
  public function MyObject():void{
    this.addEventListener(Event.ADDED_TO_STAGE, this.addedHandler, false, 0, true);
  }
  private function addedHandler(e:Event):void{
    this.x = this.stage.stageWidth/2;
  }
}

HTH

Upvotes: 0

Todd Moses
Todd Moses

Reputation: 11029

The best place is the ActionScript 3 Reference from Adobe: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/index.html

Here is the specific section on objects: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/Object.html

Upvotes: 1

Related Questions