[beginner] reference object and stage

programming flash
1

Hi all,

its me again with simple questions if you don’t mind answering.

  • i have 1 fla and 1 class file.

  • inside fla, i’ put one instance called “main” on the stage. And i put this code in frame 1:

[AS]var obj:StageHandler = new StageHandler(main);[/AS]

  • inside class file, i put this code:

[AS]package {

import flash.display.MovieClip;
import flash.display.Stage;

public class StageHandler {
    
    var _stage;
    var _main;
    
    public function StageHandler(main_obj) {
        _stage = main_obj.stage;
        _main  = main_obj;
        
        trace(_stage.stageHeight); // output: 400 
        trace(_main.height);       // output: 200
    }
}

}
[/AS]

it works perfectly. However i’m still confused with the as3 concept. in this class file, i successfully trace stage’s height and main’s height.

but, if i change the code in fla to:

[AS]var obj:StageHandler = new StageHandler(stage);[/AS]

and in class file to:
[AS]package {

import flash.display.MovieClip;
import flash.display.Stage;

public class StageHandler {
    
    var _stage;
    var _main;
    
    public function StageHandler(thisStage) {
        _stage = thisStage;
        _main  = thisStage.main;
        
        trace(_stage.stageHeight);  
        trace(_main.height); //1120: Access of undefined property main.
    }
}

}
[/AS]

i cannot trace any main’s properties. why is that? isn’t “main” inside stage?

How do i access “main” via _stage?

Thankyou all.

attached is the source.

2 
package  {
	
	import flash.display.MovieClip;
	import flash.display.Stage;
	
	public class StageHandler {
		
		var _stage;
		var _main;
		
		public function StageHandler(thisStage) {
			_stage = thisStage;
			_main  = thisStage.getChildAt(0).main;
			
			trace(_stage.stageHeight); // output: 400 
			trace(_main.height);       // output: 200
		}
	}
}

How stage, root, and MainTimeline Fit Together - by Senocular

3

believe me i’ve read those article. but still i don’t get it.

can you explain why, in details?

4

stage is an instance of Stage class and it’s Top DisplayObject (all starts here).
Then the only child of stage is root (Document Class/Main Timeline).
Ex. stage -> root -> someContainer -> myClip