# Quick noob oop question :)

**URL:** <https://forum.kirupa.com/t/quick-noob-oop-question/298169>\
**Category:** Uncategorized\
**Created:** [October 14, 2009, 5:45pm UTC](https://forum.kirupa.com/t/quick-noob-oop-question/298169 "2009-10-14T17:45:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![regbolD](https://avatars.discourse-cdn.com/v4/letter/r/ecccb3/32.png) [@regbolD](https://forum.kirupa.com/u/regbolD)\
**Post date:** [October 14, 2009, 5:45pm UTC](https://forum.kirupa.com/t/quick-noob-oop-question/298169/1 "2009-10-14T17:45:35Z")

</div>

i have 2 classes, class A and class B

in class A i instantiate class B

in class B i do this:

```auto

private var _vLineMask:LineMask;
_vLineMask = new LineMask("v", 0xffffff);
_vLineMask.addEventListener(LineMask.DONE_TRANSITION, transitionDone, false, 0, true);

```

how can i listen for that event in class A?