Example of abap program using reuse_alv_fieldcatalog_merge

Define the ABAP Program:

The function module REUSE_ALV_FIELDCATALOG_MERGE is used to automatically generate a field catalog for an ALV report. Here’s an example demonstrating how to use this function module to create an ALV report in ABAP.

The program fetches data from a database table (SFLIGHT in this case), generates a field catalog using REUSE_ALV_FIELDCATALOG_MERGE, and displays the data using REUSE_ALV_GRID_DISPLAY.

This example shows how to use REUSE_ALV_FIELDCATALOG_MERGE to simplify the creation of field catalogs for ALV reports, making it easier to manage and display data in a structured format.

				
					REPORT z_alv_example.

DATA: lt_flight_data TYPE TABLE OF sflight,
      lt_fieldcat    TYPE lvc_t_fcat,
      lv_exit        TYPE char1.

* Fetch data from the SFLIGHT table
SELECT * INTO TABLE lt_flight_data FROM sflight.

* Generate the field catalog
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
  EXPORTING
    i_structure_name = 'SFLIGHT' " Structure of the internal table
  CHANGING
    ct_fieldcat      = lt_fieldcat
  EXCEPTIONS
    inheriting_parameters = 1
    program_error         = 2
    OTHERS                = 3.

IF sy-subrc <> 0.
  WRITE: / 'Error generating field catalog'.
  EXIT.
ENDIF.

* Display the ALV report
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
  EXPORTING
    it_fieldcat = lt_fieldcat
  TABLES
    t_outtab    = lt_flight_data
  EXCEPTIONS
    program_error        = 1
    OTHERS               = 2.

IF sy-subrc <> 0.
  WRITE: / 'Error displaying ALV grid'.
ENDIF.

Explanation:

1. Data Declaration:

- lt_flight_data is an internal table of type SFLIGHT to store the flight data fetched from the database.
- lt_fieldcat is an internal table of type LVC_T_FCAT to store the field catalog.

2. Fetching Data:

- The SELECT statement retrieves all records from the SFLIGHT table and stores them in lt_flight_data.

3. Generating Field Catalog:

- The function module REUSE_ALV_FIELDCATALOG_MERGE is called with the structure name SFLIGHT.
- The generated field catalog is returned in lt_fieldcat.

4. Displaying ALV Report:

- The function module REUSE_ALV_GRID_DISPLAY is called to display the ALV report.
- it_fieldcat is passed to specify the field catalog.
- t_outtab is passed to specify the data to be displayed.

Usage:

Save and activate the above ABAP program (z_alv_example).
Execute the program. The ALV grid will display the data from the SFLIGHT table using the field catalog generated by REUSE_ALV_FIELDCATALOG_MERGE.