Detect scan keypress on Android devices

I'm using TC20/MC3300 for an inventory app using EMDK for Android Studio. I've 2 EditText, Barcode & quantity. When bar code scanning is finished focus is changed to quantity. Now user can input some value, and/or just confirm ("1") with Enter key.

However I'd like use SCAN key as Enter on quantity field.

So, how to check if SCAN button is pressed or released on Android devices ?