Creating Selection Screens Dynamically

[Former Member]

Recently in ABAP Development one of the requirement about dynamically create screen parameters? was about creating selection screen dynamically from the entries that are being maintained in the database table. Although there is no straight-forward approach for the solution, it could however be done dynamically by creating ABAP code at runtime, such that the code contains the selection screen fields and executing it. The only other option would be to include all the anticipated selection screen fields in the program and to hide the screen fields at runtime. This technique however becomes cumbersome and more coding will be required if the number of fields is too large.

Consider the following scenario:

• The user maintains a table consisting of the selection-screen parameters
• When the report program is executed a screen must be generated dynamically with only the parameters that have been defined in the table
• After the user has made entry in the selection screen, the data should be returned back to the main program and the processing should continue as per the program flow

A custom table ZSCRFLDS is created which holds the selection screen fields that is to be created.
The table structure is as follows:

The mapping between the fields of the table ZSCRFLDS and the ABAP selection screen fields is illustrated below:

Implementation of Logic:

• Retrieve the required selection screen fields specified in the table ZSCRFLDS into an internal table GT_SCRFLDS
• Create a internal table of type ABAPTEXT to store the ABAP code that is to be generated dynamically

• TABLES declaration:
  Now that we are going to create selection screen fields dynamically, we need to create TABLES declaration in ABAP code for the SELECT-OPTIONS fields.
  TABLES mara.
  SELECT-OPTIONS S_MATNR FOR MARA-MATNR.
  

  The tables workareas for the SELECT-OPTIONS fields is then generated.

• The next step is to generate the declaration for parameters and select-options.
  PARAMETERS P_MATNR LIKE MARA-MATNR.
  SELECT-OPTIONS S_MATNR FOR MARA-MATNR.
  The program code for this has been generated by checking the BASICTYP field, which specifies whether the field is a parameter or select-option.

• After creating the code for all the defined selection screen fields, we need to have a processing routine in the generated ABAP code so that the values that are entered in the selection screen are stored and returned to the main program.

  Since ABAP Shared Objects are quite unexplored, I decided to use them in the program to store the entries made in the selection screen fields into the Shared Objects Memory from which I could retrieve them.

  For those new to ABAP Shared Objects Thomas Jung’s blog on Netweaver for the Holidays: A Lession in Sharing (ABAP Shared Memory) would help.

  For implementing Shared Objects, I have created a new root class named: ZCL_SELSCR with Shared-Memory Enabled turned on. A private attribute named RANGES of the data type ACE_FIELD_RANGES_T is also created in the class.

  

  The data type ACE_FIELD_RANGES_T is a deep structure type with FIELDNAME to store selection-screen field names and a FIELDRANGE table containing the fields: OPTION, SIGN, LOW and HIGH.

  I have created two public methods for accessing this attribute.

  Method : GET_FIELDS
  
  
  Method : SET_FIELDS
  
  

  Next I created Area Class ZSELAREA using the transaction SHMA
  The code to export the data to the Shared Memory is added at the START-OF-SELECTION event of the generated program and followed by LEAVE PROGRAM to return back to the main program

• Now the generated program is created using the ABAP command INSERT REPORT:
  INSERT REPORT 'ZDYNSELSCR' FROM gt_prog.
• Now that the code is generated, we can execute the generated program in foreground using SUBMIT statement.
  SUBMIT ZDYNSELSCR VIA SELECTION-SCREEN AND RETURN.
• The program ZDYNSELSCR is executed and the selection screen is displayed. In the START-OF-SELECTION event of that program the data is uploaded to the Shared Memory.
• In the main program the selection screen entries can be read from the Shared Objects and then the further processing can be done

The ABAP Code:
REPORT  zsdn_dynselscr.*&---------------------------------------------------------------------** Global Data*&---------------------------------------------------------------------*DATA gt_scrflds TYPE TABLE OF zscrflds.DATA wa_scrflds TYPE zscrflds.DATA gt_prog TYPE TABLE OF abaptext.DATA wa_prog LIKE LINE OF gt_prog.*&---------------------------------------------------------------------** Start of Selection*&---------------------------------------------------------------------*START-OF-SELECTION.  DATA gt_tmpflds TYPE TABLE OF zscrflds.  DATA wa_tmpflds TYPE zscrflds.  DATA w_type(60) TYPE c.  DATA w_ctbix(10) TYPE c.  DATA w_desc(10) TYPE c.* Retrive the required fields from the table  SELECT *    FROM zscrflds    INTO TABLE gt_scrflds.* Build dynamic report code  wa_prog = 'REPORT zdynselscr.'.  APPEND wa_prog TO gt_prog.**Code for building TABLES section* Copy to a temporary internal table  gt_tmpflds[] = gt_scrflds[].* Delete screen fields for parameters in the temp table  DELETE gt_tmpflds WHERE basictyp NE 'S'.  SORT gt_tmpflds BY reftable.* Remove duplicates  DELETE ADJACENT DUPLICATES FROM gt_tmpflds COMPARING reftable.* Build TABLES... code for table workarea  LOOP AT gt_tmpflds INTO wa_tmpflds.    CONCATENATE 'TABLES' wa_tmpflds-reftable '.'      INTO wa_prog      SEPARATED BY space.    APPEND wa_prog TO gt_prog.  ENDLOOP.* Build Selection screen field definition  LOOP AT gt_scrflds INTO wa_scrflds.    w_ctbix = sy-tabix.    CONDENSE w_ctbix.    wa_prog = 'SELECTION-SCREEN BEGIN OF LINE.'.    APPEND wa_prog TO gt_prog.*   Comments field in the selection field    CONCATENATE      'SELECTION-SCREEN COMMENT 1(20) cmt' w_ctbix '.'      INTO wa_prog.    APPEND wa_prog TO gt_prog.*   Concatenate ref. tablename and fieldname*   Eg. : MARA / MATNR into MARA-MATNR    CONCATENATE wa_scrflds-reftable wa_scrflds-reffield      INTO w_type      SEPARATED BY '-'.*   Code generation for PARAMETERS type    IF wa_scrflds-basictyp EQ 'P'.      CONCATENATE        'PARAMETERS' wa_scrflds-fieldname 'LIKE' w_type '.'        INTO wa_prog        SEPARATED BY space.    ENDIF.*   Code generation for SELECT-OPTIONS type    IF wa_scrflds-basictyp EQ 'S'.      CONCATENATE        'SELECT-OPTIONS' wa_scrflds-fieldname 'FOR' w_type '.'        INTO wa_prog        SEPARATED BY space.    ENDIF.    APPEND wa_prog TO gt_prog.    wa_prog = 'SELECTION-SCREEN END OF LINE.'.    APPEND wa_prog TO gt_prog.  ENDLOOP.* End of code generation for selection screen* Generate Initialization event code* Initialize the comments fields defined in the selection screen  wa_prog = 'INITIALIZATION.'.  APPEND wa_prog TO gt_prog.  LOOP AT gt_scrflds INTO wa_scrflds.    w_ctbix = sy-tabix.    CONDENSE w_ctbix.    CONCATENATE 'cmt' w_ctbix      INTO w_ctbix.*   Get the description from the table DDFTX    SELECT SINGLE scrtext_s      FROM ddftx      INTO w_desc      WHERE tabname EQ wa_scrflds-reftable        AND fieldname EQ wa_scrflds-reffield        AND ddlanguage EQ sy-langu.    CONCATENATE w_ctbix ' = ''' w_desc '''.'      INTO wa_prog.    APPEND wa_prog TO gt_prog.  ENDLOOP.* Generate Start of selection event code  wa_prog = 'START-OF-SELECTION.'.  APPEND wa_prog TO gt_prog.* Data types for shared objects  wa_prog = 'DATA t_ranges TYPE ACE_FIELD_RANGES_T.'.  APPEND wa_prog TO gt_prog.  wa_prog = 'DATA wa_ranges LIKE LINE OF t_ranges.'.  APPEND wa_prog TO gt_prog.  wa_prog = 'DATA t_fldrange TYPE ACE_GENERIC_RANGE_T.'.  APPEND wa_prog TO gt_prog.  wa_prog = 'DATA wa_fldrange TYPE ACE_GENERIC_RANGE.'.  APPEND wa_prog TO gt_prog.* Read the input from the selection screen and*  store it in Shared Objects  LOOP AT gt_scrflds INTO wa_scrflds.*   Assign the fieldname in the variable    CONCATENATE 'wa_ranges-fieldname = '''                 wa_scrflds-fieldname '''.'      INTO wa_prog SEPARATED BY space.    APPEND wa_prog TO gt_prog.    wa_prog = 'REFRESH t_fldrange.'.    APPEND wa_prog TO gt_prog.*   Processing for SELECT-OPTIONS*   Loop and move data to the shared memory    IF wa_scrflds-basictyp EQ 'S'.      CONCATENATE 'LOOP AT ' wa_scrflds-fieldname '.'        INTO wa_prog SEPARATED BY space.      APPEND wa_prog TO gt_prog.      wa_prog = 'CLEAR wa_fldrange.'.      APPEND wa_prog TO gt_prog.      CONCATENATE 'MOVE-CORRESPONDING ' wa_scrflds-fieldname 'TO' 'wa_fldrange.'         INTO wa_prog SEPARATED BY space.      APPEND wa_prog TO gt_prog.      wa_prog = 'APPEND wa_fldrange TO t_fldrange.'.      APPEND wa_prog TO gt_prog.      wa_prog = 'ENDLOOP.'.      APPEND wa_prog TO gt_prog.      wa_prog = 'wa_ranges-fieldrange[] = t_fldrange[].'.      APPEND wa_prog TO gt_prog.      wa_prog = 'APPEND wa_ranges TO t_ranges.'.      APPEND wa_prog TO gt_prog.    ELSEIF wa_scrflds-basictyp EQ 'P'.*   Processing for PARAMETERS      wa_prog = 'CLEAR wa_fldrange.'.      APPEND wa_prog TO gt_prog.*     Process if the parameter is not initial      CONCATENATE 'IF ' wa_scrflds-fieldname 'IS NOT INITIAL.'        INTO wa_prog SEPARATED BY space.      APPEND wa_prog TO gt_prog.      wa_prog = 'wa_fldrange-sign = ''I''.'.      APPEND wa_prog TO gt_prog.      wa_prog = 'wa_fldrange-option = ''EQ''.'.      APPEND wa_prog TO gt_prog.      CONCATENATE 'wa_fldrange-low = ' wa_scrflds-fieldname '.'        INTO wa_prog SEPARATED BY space.      APPEND wa_prog TO gt_prog.      wa_prog = 'APPEND wa_fldrange TO t_fldrange.'.      APPEND wa_prog TO gt_prog.      wa_prog = 'ENDIF.'.      APPEND wa_prog TO gt_prog.      wa_prog = 'wa_ranges-fieldrange[] = t_fldrange[].'.      APPEND wa_prog TO gt_prog.      wa_prog = 'APPEND wa_ranges TO t_ranges.'.      APPEND wa_prog TO gt_prog.    ENDIF.  ENDLOOP.  wa_prog = 'DATA: area type ref to ZSELAREA.'.  APPEND wa_prog TO gt_prog.  wa_prog = 'DATA root type REF to ZCL_SELSCR.'.  APPEND wa_prog TO gt_prog.* Get ref to the shared memory  wa_prog = 'area = zselarea=>attach_for_write( ).'.  APPEND wa_prog TO gt_prog.  wa_prog = 'create object root area handle area.'.  APPEND wa_prog TO gt_prog.* Store the value in the memory  wa_prog = 'root->set_fields( t_ranges ).'.  APPEND wa_prog TO gt_prog.  wa_prog = 'area->set_root(  root ).'.  APPEND wa_prog TO gt_prog.* Commit and detatch  wa_prog = 'area->detach_commit( ).'.  APPEND wa_prog TO gt_prog.* Quit the program: Return to the main code  wa_prog = 'LEAVE PROGRAM.'.  APPEND wa_prog TO gt_prog.* Generate the report program  INSERT REPORT 'ZDYNSELSCR' FROM gt_prog.  COMMIT WORK.* Execute the report  SUBMIT zdynselscr VIA SELECTION-SCREEN AND RETURN.*  Read the data from the shared memory  DATA area TYPE REF TO zselarea.  area = zselarea=>attach_for_read( ).  DATA t_ranges TYPE ace_field_ranges_t.  t_ranges = area->root->get_fields( ).  area->detach( ).  TYPES cond(72) TYPE c.  DATA it_vbak TYPE TABLE OF vbak.  DATA wa_vbak LIKE LINE OF it_vbak.  DATA t_cond TYPE TABLE OF cond WITH HEADER LINE.  DATA wa_ranges LIKE LINE OF t_ranges.  DATA wa_fieldrange LIKE LINE OF wa_ranges-fieldrange.  DATA dref TYPE REF TO data.  LOOP AT t_ranges INTO wa_ranges.    WRITE / wa_ranges-fieldname COLOR COL_HEADING.    ULINE AT /8(68).    LOOP AT wa_ranges-fieldrange INTO wa_fieldrange.      WRITE :/8 sy-vline, 10 wa_fieldrange-sign,              14 sy-vline, 15 wa_fieldrange-option,              19 sy-vline, 20 wa_fieldrange-low, 42 sy-vline, 75 sy-vline.      IF wa_fieldrange-high IS NOT INITIAL.        WRITE AT 43 wa_fieldrange-high.        WRITE AT 75 sy-vline.      ENDIF.    ENDLOOP.    ULINE AT /8(68).  ENDLOOP.

ZSCRFLDS - Table Entries


Selection Screen Output


Display of the entries made in the selection screen

However, this is a sample program which illustrates handling parameters and select-options. However this could be extended to include checkboxes and radiobuttons and other selection screen fields.

I was rather unsuccessful in maintaining the text-elements of the selection-screen fields dynamically using code. I have temporarily solved the problem using selection-screen COMMENT fields and initializing these variables in the INITIALIZATION event. It would have been better if I could find a way to sort this out.

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