Resizing and using Desktop and Android?

Hey everyone, im sure this question popup up not once and not twice, but i still dont get it no matter how much i try.

when i design an app using my Desktop PC, i ran the Emulator builded in Adobe Animate, i see the page like this:

thats how it supposed to look on the Android also (but its not)

im using this commands to Align and scale:

stage.scaleMode = StageScaleMode.EXACT_FIT;

stage.align = StageAlign.TOP;

and after that, i use the next command to Calculate the Screen Weight so i can place the buttons using code:

var ScreenWidth = stage.fullScreenWidth;

so with ScreenWidth i know the exact positions to place my buttons and what size the buttons should be according the the same Width of the screen.

but on my android, i see it like this:

please help me understand why thats happening and how i fix that.

Thanks.