ALV report using the field catalog

Question

which is the quickest way to generate an ALV report using the field catalog merge.  without needing to build the field catalog manually .
is it easier to create a structure and passe it in the field catalog merge .  if yes can i have an example plzzzz

Answer 1

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Supports the creation of the field catalog for the ALV function modules
based either on a structure or table defined in the ABAP Data
Dictionary, or a program-internal table.
The program-internal table must either be in a TOP Include or its
Include must be specified explicitly in the interface.
The variant based on a program-internal table should only be used for
rapid prototyping since the following restrictions apply:
o Performance is affected since the code of the table definition must
always be read and interpreted at runtime.
o Dictionary references are only considered if the keywords LIKE or
INCLUDE STRUCTURE (not TYPE) are used.
If the field catalog contains more than 90 fields, the first 90 fields
are output in the list by default whereas the remaining fields are only
available in the field selection.
If the field catalog is passed with values, they are merged with the
'automatically' found information.
Below is an example ABAP program which will populate a simple internal table(it_ekpo) with data and
display it using the basic ALV grid functionality(including column total). The example details the main
sections of coding required to implement the ALV grid functionality:
                         Data declaration
                         Data retrieval
                         Build fieldcatalog
                         Build layout setup
*& Report  ZDEMO_ALVGRID                                               *
*& Example of a simple ALV Grid Report                                 *
*& The basic requirement for this demo is to display a number of       *
*& fields from the EKKO table.                                         *
REPORT  zdemo_alvgrid                 .
TABLES:     ekko.
type-pools: slis.                                 "ALV Declarations
*Data Declaration
TYPES: BEGIN OF t_ekko,
  ebeln TYPE ekpo-ebeln,
  ebelp TYPE ekpo-ebelp,
  statu TYPE ekpo-statu,
  aedat TYPE ekpo-aedat,
  matnr TYPE ekpo-matnr,
  menge TYPE ekpo-menge,
  meins TYPE ekpo-meins,
  netpr TYPE ekpo-netpr,
  peinh TYPE ekpo-peinh,
END OF t_ekko.
DATA: it_ekko TYPE STANDARD TABLE OF t_ekko INITIAL SIZE 0,
      wa_ekko TYPE t_ekko.
*ALV data declarations
data: fieldcatalog type slis_t_fieldcat_alv with header line,
      gd_tab_group type slis_t_sp_group_alv,
      gd_layout    type slis_layout_alv,
      gd_repid     like sy-repid.
*Start-of-selection.
START-OF-SELECTION.
perform data_retrieval.
perform build_fieldcatalog.
perform build_layout.
perform display_alv_report.
*&      Form  BUILD_FIELDCATALOG
*       Build Fieldcatalog for ALV Report
form build_fieldcatalog.
* There are a number of ways to create a fieldcat.
* For the purpose of this example i will build the fieldcatalog manualy
* by populating the internal table fields individually and then
* appending the rows. This method can be the most time consuming but can
* also allow you  more control of the final product.
* Beware though, you need to ensure that all fields required are
* populated. When using some of functionality available via ALV, such as
* total. You may need to provide more information than if you were
* simply displaying the result
*               I.e. Field type may be required in-order for
*                    the 'TOTAL' function to work.
  fieldcatalog-fieldname   = 'EBELN'.
  fieldcatalog-seltext_m   = 'Purchase Order'.
  fieldcatalog-col_pos     = 0.
  fieldcatalog-outputlen   = 10.
  fieldcatalog-emphasize   = 'X'.
  fieldcatalog-key         = 'X'.
*  fieldcatalog-do_sum      = 'X'.
*  fieldcatalog-no_zero     = 'X'.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'EBELP'.
  fieldcatalog-seltext_m   = 'PO Item'.
  fieldcatalog-col_pos     = 1.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'STATU'.
  fieldcatalog-seltext_m   = 'Status'.
  fieldcatalog-col_pos     = 2.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'AEDAT'.
  fieldcatalog-seltext_m   = 'Item change date'.
  fieldcatalog-col_pos     = 3.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'MATNR'.
  fieldcatalog-seltext_m   = 'Material Number'.
  fieldcatalog-col_pos     = 4.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'MENGE'.
  fieldcatalog-seltext_m   = 'PO quantity'.
  fieldcatalog-col_pos     = 5.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'MEINS'.
  fieldcatalog-seltext_m   = 'Order Unit'.
  fieldcatalog-col_pos     = 6.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'NETPR'.
  fieldcatalog-seltext_m   = 'Net Price'.
  fieldcatalog-col_pos     = 7.
  fieldcatalog-outputlen   = 15.
  fieldcatalog-do_sum      = 'X'.        "Display column total
  fieldcatalog-datatype     = 'CURR'.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
  fieldcatalog-fieldname   = 'PEINH'.
  fieldcatalog-seltext_m   = 'Price Unit'.
  fieldcatalog-col_pos     = 8.
  append fieldcatalog to fieldcatalog.
  clear  fieldcatalog.
endform.                    " BUILD_FIELDCATALOG
*&      Form  BUILD_LAYOUT
*       Build layout for ALV grid report
form build_layout.
  gd_layout-no_input          = 'X'.
  gd_layout-colwidth_optimize = 'X'.
  gd_layout-totals_text       = 'Totals'(201).
*  gd_layout-totals_only        = 'X'.
*  gd_layout-f2code            = 'DISP'.  "Sets fcode for when double
*                                         "click(press f2)
*  gd_layout-zebra             = 'X'.
*  gd_layout-group_change_edit = 'X'.
*  gd_layout-header_text       = 'helllllo'.
endform.                    " BUILD_LAYOUT
*&      Form  DISPLAY_ALV_REPORT
*       Display report using ALV grid
form display_alv_report.
  gd_repid = sy-repid.
  call function 'REUSE_ALV_GRID_DISPLAY'
       exporting
            i_callback_program      = gd_repid
*            i_callback_top_of_page   = 'TOP-OF-PAGE'  "see FORM
*            i_callback_user_command = 'USER_COMMAND'
*            i_grid_title           = outtext
            is_layout               = gd_layout
            it_fieldcat             = fieldcatalog[]
*            it_special_groups       = gd_tabgroup
*            IT_EVENTS                = GT_XEVENTS
            i_save                  = 'X'
*            is_variant              = z_template
       tables
            t_outtab                = it_ekko
       exceptions
            program_error           = 1
            others                  = 2.
  if sy-subrc <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  endif.
endform.                    " DISPLAY_ALV_REPORT
*&      Form  DATA_RETRIEVAL
*       Retrieve data form EKPO table and populate itab it_ekko
form data_retrieval.
select ebeln ebelp statu aedat matnr menge meins netpr peinh
up to 10 rows
  from ekpo
  into table it_ekko.
endform.                    " DATA_RETRIEVAL