Android :: Selector For Buttons Not Working After Setting BackgroundResource

I have applied the follwoing selector to all my buttons by specifying it in my theme:

CODE:...............

This works fine. But I want the background of the button to remain "@drawable/my_btn_pressed" when the button is pressed, as if to highlight that this was the last button pressed. Hence, I added the code in my onClick() to set the background resource:

CODE:.............

This also works to highlight the last pressed button with "my_btn_pressed". However after this, my selector properties do not seem to work on the other buttons. Mainly, the state focussed is not distinguishable, at all.

How I can do both, i.e distinguish focussed, pressed and normal states of the button, as well as highlight the last pressed button?