Convert text item into Check box and assign values

Hi all

I am new in abap, I have created a program and define some screen elements from dictionary through screen painter, one of my item name is ZUT_APARTMENT-HAS_AC and its type is text and contain fixed values like a 1) A (means active) and 2) N (means not active). My question is that how can I convert this text item into Check box and when user apply check then it contain value "A" and when user uncheck it then it contain value "D".

Thanks