ALV with dynamic columns and description labels in header titles

Question

Hi everybody,
I have to implement an ALV whose columns are not defined until runtime. Is it possible to do that in some simple way? Is it necessary to use objects to define this kind of ALV's?
And another one query, is it possible to add description labels to column headers so that when the user points with the cursor in them he/she gets a little explanation about the detail of the column (for example, description name of the product hierarchy when pointing to the column named with one of the existing hierarchies, i.e 010102102)
Thanks in advance,

Answer 1

for your first question check this
Just check this sample from one of the SAP site
ABAP Code Sample for Dynamic Table for ALV with Cell Coloring
Applies To:
ABAP / ALV Grid
Article Summary
ABAP Code Sample that uses dynamic programming techniques to build a dynamic internal table for display in an ALV Grid with Cell Coloring.
Code Sample
REPORT zcdf_dynamic_table.
* Dynamic ALV Grid with Cell Coloring.
* Build a field catalog dynamically and provide the ability to color
* the cells.
* To test, copy this code to any program name and create screen 100
* as described in the comments. After the screen is displayed, hit
* enter to exit the screen.
* Tested in 4.6C and 6.20
* Charles Folwell - [email protected] - Feb 2, 2005
DATA:
r_dyn_table TYPE REF TO data,
r_wa_dyn_table TYPE REF TO data,
r_dock_ctnr TYPE REF TO cl_gui_docking_container,
r_alv_grid TYPE REF TO cl_gui_alv_grid,
t_fieldcat1 TYPE lvc_t_fcat, "with cell color
t_fieldcat2 TYPE lvc_t_fcat, "without cell color
wa_fieldcat LIKE LINE OF t_fieldcat1,
wa_cellcolors TYPE LINE OF lvc_t_scol,
wa_is_layout TYPE lvc_s_layo.
FIELD-SYMBOLS:
<t_dyn_table> TYPE STANDARD TABLE,
<wa_dyn_table> TYPE ANY,
<t_cellcolors> TYPE lvc_t_scol,
<w_field> TYPE ANY.
START-OF-SELECTION.
* Build field catalog based on your criteria.
wa_fieldcat-fieldname = 'FIELD1'.
wa_fieldcat-inttype = 'C'.
wa_fieldcat-outputlen = '10'.
wa_fieldcat-coltext = 'My Field 1'.
wa_fieldcat-seltext = wa_fieldcat-coltext.
APPEND wa_fieldcat TO t_fieldcat1.
wa_fieldcat-fieldname = 'FIELD2'.
wa_fieldcat-inttype = 'C'.
wa_fieldcat-outputlen = '10'.
wa_fieldcat-coltext = 'My Field 2'.
wa_fieldcat-seltext = wa_fieldcat-coltext.
APPEND wa_fieldcat TO t_fieldcat1.
* Before adding cell color table, save fieldcatalog to pass
* to ALV call. The ALV call needs a fieldcatalog without
* the internal table for cell coloring.
t_fieldcat2[] = t_fieldcat1[].
* Add cell color table.
* CALENDAR_TYPE is a structure in the dictionary with a
* field called COLTAB of type LVC_T_SCOL. You can use
* any structure and field that has the type LVC_T_SCOL.
wa_fieldcat-fieldname = 'T_CELLCOLORS'.
wa_fieldcat-ref_field = 'COLTAB'.
wa_fieldcat-ref_table = 'CALENDAR_TYPE'.
APPEND wa_fieldcat TO t_fieldcat1.
* Create dynamic table including the internal table
* for cell coloring.
CALL METHOD cl_alv_table_create=>create_dynamic_table
EXPORTING
it_fieldcatalog = t_fieldcat1
IMPORTING
ep_table = r_dyn_table
EXCEPTIONS
generate_subpool_dir_full = 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.
* Get access to new table using field symbol.
ASSIGN r_dyn_table->* TO <t_dyn_table>.
* Create work area for new table.
CREATE DATA r_wa_dyn_table LIKE LINE OF <t_dyn_table>.
* Get access to new work area using field symbol.
ASSIGN r_wa_dyn_table->* TO <wa_dyn_table>.
* Get data into table from somewhere. Field names are
* known at this point because field catalog is already
* built. Read field names from the field catalog or use
* COMPONENT <number> in a DO loop to access the fields. A
* simpler hard coded approach is used here.
ASSIGN COMPONENT 'FIELD1' OF STRUCTURE <wa_dyn_table> TO <w_field>.
<w_field> = 'ABC'.
ASSIGN COMPONENT 'FIELD2' OF STRUCTURE <wa_dyn_table> TO <w_field>.
<w_field> = 'XYZ'.
APPEND <wa_dyn_table> TO <t_dyn_table>.
ASSIGN COMPONENT 'FIELD1' OF STRUCTURE <wa_dyn_table> TO <w_field>.
<w_field> = 'TUV'.
ASSIGN COMPONENT 'FIELD2' OF STRUCTURE <wa_dyn_table> TO <w_field>.
<w_field> = 'DEF'.
APPEND <wa_dyn_table> TO <t_dyn_table>.
* Color cells based on your criteria. In this example, a test on
* FIELD2 is used to decide on color.
LOOP AT <t_dyn_table> INTO <wa_dyn_table>.
ASSIGN COMPONENT 'FIELD2' OF STRUCTURE <wa_dyn_table> TO <w_field>.
* Get access to internal table used to color cells.
ASSIGN COMPONENT 'T_CELLCOLORS'
OF STRUCTURE <wa_dyn_table> TO <t_cellcolors>.
CLEAR wa_cellcolors.
wa_cellcolors-fname = 'FIELD2'.
IF <w_field> = 'DEF'.
wa_cellcolors-color-col = '7'.
ELSE.
wa_cellcolors-color-col = '5'.
ENDIF.
APPEND wa_cellcolors TO <t_cellcolors>.
MODIFY <t_dyn_table> FROM <wa_dyn_table>.
ENDLOOP.
* Display screen. Define screen 100 as empty, with next screen
* set to 0 and flow logic of:
* PROCESS BEFORE OUTPUT.
* MODULE initialization.
* PROCESS AFTER INPUT.
CALL SCREEN 100.
* MODULE initialization OUTPUT
MODULE initialization OUTPUT.
* Set up for ALV display.
IF r_dock_ctnr IS INITIAL.
CREATE OBJECT r_dock_ctnr
EXPORTING
side = cl_gui_docking_container=>dock_at_left
ratio = '90'.
CREATE OBJECT r_alv_grid
EXPORTING i_parent = r_dock_ctnr.
* Set ALV controls for cell coloring table.
wa_is_layout-ctab_fname = 'T_CELLCOLORS'.
* Display.
CALL METHOD r_alv_grid->set_table_for_first_display
EXPORTING
is_layout = wa_is_layout
CHANGING
it_outtab = <t_dyn_table>
it_fieldcatalog = t_fieldcat2.
ELSE. "grid already prepared
* Refresh display.
CALL METHOD r_alv_grid->refresh_table_display
EXPORTING
i_soft_refresh = ' '
EXCEPTIONS
finished = 1
OTHERS = 2.
ENDIF.
ENDMODULE. " initialization OUTPUT