Flash Actionscript AS2 - Access instance variable defined on the timeline from within a class

Question

I might be missing something. I thought this would be a common question but extensive search on the web over a few days didn't turn up the answer I need. I am hoping to make a self-contained movie clip that would function wherever it is placed. However, it seems difficult to access instances defined in the movie clip from within a class that extends the movie clip.

Although I am coding in Flash Actionscript 2 (AS2), I wonder if the same issue exists for AS3.

In the following scenario, how do you access the instance "circle"?

A movie clip on the main timeline has an instance name "square". A class Square defined in Square.as extends this movie clip. Inside the movie clip, another movie clip is placed on the first frame, with instance name "circle". There is also a varialbe declared on the first frame var myName:String = "my name". The following code doesn't compile:

class Square extends MovieClip {
      function Square() {
          trace("Square.constructor, circle: " + circle);
          trace(" --- myName: " + myName);
      }
}

Compiler errors: There is no property with name 'circle'. (same for myName).

Adding this. in the reference doesn't help. Apparently, the compiler is looking for the varialbles in the class definition.

Using _level0.square.circle works, but that requires the class to know its own instance path. While _level0.square.myName doesn't produce compiler errors, it gives a value of undefined.

Referencing these variables in methods other than the constructor causes the same compiler errors.

Thanks much for your help.

Hey user1789547, maybe if the instance resides on the stage you have to pass the stage reference into the class? I know your question is about AS2, but this might be some help : actionscript.org/forums/showthread.php3?t=250599 — Mike
Thanks, Mike. I saw that or similar discussions during my search. But they were trying to reference something outside of the class, while I was trying to reference something inside, a child movie clip within the parent movie clip that the class is extending. Logically, as least I thought, the extending class would have access to everything that the parent movie clip had access to. -Keith — Braeburn

Braeburn Braeburn · Accepted Answer · 2012-11-01T19:48:22

I found a way to solve the problem, using eval(this).

class Square extends MovieClip {
    var base:MovieClip;

    function Square() {
        base = eval(this);
        trace("Square.constructor, circle: " + base.circle);
        trace(" --- myName: " + base.myName);
        onPress = procPress;
    }

    function procPress() {
        trace("procPress: " + base.circle);
        trace("procPress: " + base.myName);
    }
}

No compiler errors. In the constructor, base.myName is still undefined (understandable). In the function procPress invoked by a click, base.myName has the correct value.

Flash Actionscript AS2 - Access instance variable defined on the timeline from within a class

1 Answers