Add Button to ALV Toolbar with REUSE_ALV_LIST_DISPLAY

In the program which calls ALV using REUSE_ALV_LIST_DISPLAY, you need to add a new button.
I saw the demo program BCALV_GRID_08, which is written using ABAP-Controls.
In that example, the button is added using TOOLBAR event of cl_gui_alv_grid. This is how to do it using REUSE_ALV_LIST_DISPLAY parameters.

you should copy the 'STANDARD' GUI status from program SAPLKKBL using transaction SE90 -->Programming SubObjects--> Gui Status.

Execute this transaction to get to next screen. select status using checkbox. click on GUI Status --> Copy.

Enter your Z program name and the name you what for this status - you can keep it as 'STANDARD' to be simple.

Then you can edit the new status to add or delete buttons. This will also bring in the standard SAP ALV functionality such as sorting/subtotaling etc...

When you call 'REUSE_ALV_GRID_DISPLAY' make sure you pass it the new status name.

an example of one of mine:
call function 'REUSE_ALV_GRID_DISPLAY'
EXPORTING
i_callback_program = 'ZSDBOLST_REPORT'
i_callback_pf_status_set = 'STANDARD' <---------
i_callback_user_command = 'USER_COMMAND'
i_structure_name = 'I_BOLACT'
i_grid_title = 'BOL Action Report'(031)
is_layout = gs_layout
it_fieldcat = gt_fieldcat[]
i_save = 'A'
is_variant = v_variant
TABLES
t_outtab = i_bolact
EXCEPTIONS
program_error = 1
others = 2.

---

As identified with the FM's help you can do the following.

1). Using SE80 (I think) you can copy a GUI status from one program to another. It mentions which one in the FM's help.
2). Create a form named like so:

Code:
*****************************************************************
* Form Set_pf_status
* Notes: Called by FM REUSE_ALV_GRID_DISPLAY
*****************************************************************
FORM set_pf_status USING rt_extab TYPE slis_t_extab.
SET PF-STATUS 'ZSTANDARD'.
ENDFORM. "Set_pf_status

In the above case the GUI status copied was named ZSTANDARD and adjusted accordingly, adding and removing the desired buttons. A button was added called '%DELETE'.

3). Create the following report:
Code:
*****************************************************************
* Form User_command
* Notes: Called by FM REUSE_ALV_GRID_DISPLAY
* Detects whether the icon/button for
* 'Return Tag Deletion' has been pressed. If it has then
* detect whether any rows have been highlighted and then
* set the delete flag.
*****************************************************************
FORM user_command USING r_ucomm LIKE sy-ucomm
rs_selfield TYPE slis_selfield.
DATA: li_count TYPE I.
IF r_ucomm EQ '%DELETE'.
LOOP AT %g00 WHERE mark EQ 'X'.
ADD 1 TO li_count.
ENDLOOP.
IF li_count GT 0.
gc_delete_flag = 'X'.
r_ucomm = '&F03'. "Back arraow
ELSE.
MESSAGE W000 WITH 'Please highlight the rows to be deleted!'.
ENDIF.
ENDIF.
ENDFORM. "User_command

As I've added an extra button to indicate which records should be deleted I need to identify a form to be called to process when this button is chosen.

Then when you call the ALV function you to specify the following extra details:

Code:
call function 'REUSE_ALV_GRID_DISPLAY'
exporting i_callback_program = gc_repid
I_CALLBACK_PF_STATUS_SET = 'SET_PF_STATUS'
I_CALLBACK_USER_COMMAND = 'USER_COMMAND'
i_grid_title = lc_grid_title
is_layout = lc_layout
it_fieldcat = gt_fieldcat
it_sort = sort
i_save = l_save
is_reprep_id = l_bbs_id
is_variant = l_variant
tables t_outtab = %g00
exceptions program_error = 1
others = 2.

The parameters in capitals are the extra ones that need to be added.

That should be it!