How to access the stage from an AS3 class in Adobe Flash

actionscript-3classflashkeyboardstage

The problem I've encountered is that I am using a keyboardEventListener to make a movieclip run around. As I'm a college student, I'm creating this for an assignment but we are forced to use as3 classes.

When I run the code in the maintimeline, there is no problem. But when I try to access it from another class (with an 'Export for ActionScript' on the movieclip in question) I get an error he can't address the stage.

this.stage.addEventListener(KeyboardEvent.KEY_DOWN, dostuff);

Best Answer

A class in AS3 is not on the stage until you actually place it there. As a result, "this.stage" will be null at compile time. You can get around this problem by using the ADDED_TO_STAGE event to delay binding your listeners until the time is right.

public function MyClass(){
    this.addEventListener(Event.ADDED_TO_STAGE, addedToStageHandler);
}

private function addedToStageHandler(e:Event):void{
    this.stage.addEventListener(KeyboardEvent.KEY_DOWN, dostuff);
}

Related Solutions

R – How to access a stage instance name from a SWF embedded w/ the Flex compiler

you need to both give them instance names in the IDE and declare them in the class you've embedded them on.

So say that you have instances of baz and frr on your embedded class InfoPopup, you need to declare them like this:

package foo {

    import flash.display.Sprite;    

    [Embed(source='../../../../../../assets/Assets.swf', symbol='InfoPopup')]
    public class InfoPopup extends Sprite {

        public var baz:Sprite;
        public var baz:MovieClip;

        public function InfoPopup(){
                trace("constructor!");
        }

    }

}

When added like this they have to be public properties or else the compiler will complain.

Access main stage from class definition file (as3)

your class definition is really weird. Looks like a mixture of as2 and as3.
Try with this:

package
{
import flash.display.MovieClip;
import flash.events.MouseEvent;
import flash.text.*;
import fl.controls.Button;
public class Answers extends MovieClip
{

    public var answersArray:Array = new Array();

    public function Answers()
    {
        submit_btn.addEventListener(MouseEvent.CLICK, remove);
    }

    private function remove(e:MouseEvent)
    {
        answersArray.push(answer_txt.text);
        this.parent.removeChild(this);
    }

}

}

This works on my computer. Your code doesn't. I think it has something to do with the listen method. The class isn't still instatiated and you are making it work.

Best Answer

Related Solutions

R – How to access a stage instance name from a SWF embedded w/ the Flex compiler

Access main stage from class definition file (as3)

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