on component showing Modal default event is still triggered

[winadiw]

So i have component that show Modal to user, then i want the user to press volume up or down. I already set up the onKeyUp and onKeyDown on MainActivity.java to return true, so default behaviour will be do nothing. Without showing the modal, if user press volume up or down key, there will be no volume slider. But if using modal, if user press the volume key, then the Android volume slider will show. How to hide the system volume slider if using Modal?