I came across this link :
Assign width to half available screen width declaratively
How to do the same in relative layout? Here\'s the code: Trying linea
This is a nice workaround if you precisely need half, when using RelativeLayout. What you do is, make a fake invisible view centered in parent, and have left button be alignParentLeft and alignRight to that fake view and the right button vice-versa
Its really clever.