do you mean alv grid or alv list.
If you use function module REUSE_ALV_GRID_DISPLAY then you should use the inputparamter i_callback_pf_status_set to set the pf-status and add a button. By setting the parameter i_callback_user_command (will be a name of a perform in your report) you will be able to filter which action has been performed by the user.
I do have an example for this - i'll keep on searchin
Don't hesitate to post any questions.