What are function modules used in alv,and its explanation

Question

what are function modules used in alv,and its explanation

Answer 1

hi..
The important function modules are
Reuse_alv_fieldcatalog_merge
Reuse_alv_list_display
Reuse_alv_events_get
Reuse_alv_grid_display
Reuse_alv_commentary_write.
<b>REUSE_ALV_FIELDCATALOG_MERGE</b>
      This function module is used to populate a field catalog which is essential to display the data in ALV.
      If the output data is from a single dictionary table and all the columns are selected, then we need not exclusively create the field catalog. Its enough to mention the table name as a parameter (I_structure_name) in the REUSE_ALV_LIST_DISPLAY. But in other cases we need to create it.
Note : Fieldcatalog can be filled manually also by filling up all the required details into the internal table     
The important parameters are:
   1. Export:
        a. I_program_name     : report id
        b. I_internal_tabname     : the internal output table     
        c. I_inclname     : include or the report name where all  
                                             the dynamic forms are handled.
    2. Changing
       ct_fieldcat     :    an internal table with the type 
                                  SLIS_T_FIELDCAT_ALV which is declared in the
                                  type pool SLIS.
<b>REUSE_ALV_LIST_DISPLAY</b>
This is the function module which prints the data.
The important parameters are:
1. Export:
      I_callback_program            : report id
      I_bypassing_buffer             : ‘X’
      I_buffer_active                    : ‘ ‘
      I_callback_pf_status_set     : routine where a user can set
                                                         his own pf status or change the
                                                         functionality of the existing pf status.
      I_callback_user_command : routine where the function codes are
                                                           handled.
      I_structure name     : name of the dictionary table
      Is_Layout          : structure to set the layout of the report
      It_fieldcat          : internal table with the list of all fields and their
                                             attributes which are to be printed (this table
                                             can be populated automatically by the function
                                             REUSE_ALV_FIELDCATALOG_MERGE
      It_events          : internal table with a list of all possible events
                                             of ALV and their corresponding form names.
2.  Tables:
     a. t_outtab     : internal table with the data to be output
<b>REUSE_ALV_EVENTS_GET: </b>
      Returns table of possible events for a a list type
1. Import:
      Et_Events      :
      The event table is returned with all possible CALLBACK events for the specified list type (column ‘NAME’). For events to be processed by the Callback, their ‘FORM’ field must be filled. If the field is initialized, the event is ignored. The entry can be read from the event table, the field ‘FORM’ filled and the entry modified using constants from the type pool SLIS.
2. Export:
    I_list_type:
          0 = simple list REUSE_ALV_LIST_DISPLAY
          1 = hierarchical-sequential list                                           
                REUSE_ALV_HIERSEQ_LIST_DISPLAY
          2 = simple block list                                                        REUSE_ALV_BLOCK_LIST_APPEND
          3 = hierarchical-sequential block list
                REUSE_ALV_BLOCK_LIST_HS_APPEND
<b>REUSE_ALV_GRID_DISPLAY</b>
  A new function from 4.6 version, to display the results in grid rather than a
  preview.
  Parameters : same as reuse_alv_list_display
<b>REUSE_ALV_COMMENTARY_WRITE</b>
This is used in the Top-of-page event  to print the headings and other
comments for the list.
It_list_commentary : Internal table with the headings of the type
                                         slis_t_listheader.
    This internal table has three fields:
    Typ : ‘H’ - header, ‘S’ - selection, ‘A’ - action
    Key : only when typ is ‘S’.
    Info : the text to be printed
<b>plz reward pts if helpful.</b>
regards
vijay.