Dynamic fields to be displayed in ALV

Question

Hi All,
I've a requirement like this.
I have table type with 10 fields and I use this to display data in ALV.  Now, I need to add few dynamic columns (based on customizing) and show in the same ALV.  Since these fields are dynamic and new fields can also be added in the future, I can not enhance the structure I am using at present.  So, the solution would be to add dynamic columns to the output table that is sent to ALV display.
Adding fields to field catalogue is not a big ask and I am already done with that.  Moreover, I have tried enhancing the current structure with a field of type DATA and populated it. 
But, technically, it is a single field and cannot be split into the different new fields at the time of output. 
How is this possible?  Please provide me with example code also, if you have.
Thanks in advance,
Srinath.

Answer 1

Hi Srinath,
I for this purpose I use my own solution since a couple of years with success. It was originally developed for ALV functions module. In OO the field catalo has a slightly different structure, nut one can be easily converted into the other using function module (don't remember the name right now).
Recently I created a class with static functional methods for this:
METHOD fieldcat_alv .
  TYPE-POOLS:
    sydes.
  DATA:
    lv_desc                               TYPE sydes_desc,
    ls_alv_fieldcat                       TYPE slis_fieldcat_alv,
    lv_longfield                          TYPE dynfnam.
  FIELD-SYMBOLS:
    <typeinfo>                            TYPE sydes_typeinfo,
    <nameinfo>                            TYPE sydes_nameinfo.
  DESCRIBE FIELD it_table INTO lv_desc.                     "#EC *
  LOOP AT lv_desc-types
      ASSIGNING <typeinfo>
      WHERE NOT idx_name IS INITIAL
        AND table_kind IS INITIAL "no entries for deep table like color
        AND back                          = 2. "top-level-entries only.
    READ TABLE lv_desc-names INDEX <typeinfo>-idx_name
      ASSIGNING <nameinfo>.
    CHECK <nameinfo>-name                 <> 'INCLUDE'.
    ls_alv_fieldcat-fieldname             = <nameinfo>-name.
    WHILE NOT <nameinfo>-continue IS INITIAL.
      ADD 1 TO <typeinfo>-idx_name.
      READ TABLE lv_desc-names INDEX <typeinfo>-idx_name
        ASSIGNING <nameinfo>.
      CONCATENATE
        ls_alv_fieldcat-fieldname
        <nameinfo>-name
        INTO ls_alv_fieldcat-fieldname.
    ENDWHILE." not <nameinfo>-continue IS INITIAL.
    READ TABLE lv_desc-names INDEX <typeinfo>-idx_help_id
      ASSIGNING <nameinfo>.
    IF sy-subrc                           = 0.
* Caution: Help-ID may be Tablename-Fieldname and thus longer
* than 30 Chars; ls_alv_fieldcat-rollname is 30 Chars only
      ls_alv_fieldcat-rollname            = <nameinfo>-name.
      lv_longfield                        = <nameinfo>-name.
      WHILE NOT <nameinfo>-continue IS INITIAL.
        ADD 1 TO <typeinfo>-idx_help_id.
        READ TABLE lv_desc-names INDEX <typeinfo>-idx_help_id
          ASSIGNING <nameinfo>.
        CONCATENATE
          lv_longfield
          <nameinfo>-name
          INTO lv_longfield.
      ENDWHILE." not lv_desc-continue is initial.
* help id may be data element or <table>-<field>
      IF lv_longfield CA '-'.
* get datatype for table field
        CALL METHOD get_rollname_4_tabfield
          EXPORTING
            iv_fieldname    = lv_longfield
          CHANGING
            cs_alv_fieldcat = ls_alv_fieldcat.
      ENDIF." lv_longfield ca '-'.
    ELSE.
* No Help-ID: Use Fieldname as text
      ls_alv_fieldcat-seltext_s           =
      ls_alv_fieldcat-seltext_m           =
      ls_alv_fieldcat-seltext_l           =
      ls_alv_fieldcat-reptext_ddic        =
      <nameinfo>-name.
    ENDIF." sy-subrc                      = 0.
* Starting 4.7: get edit mask
    IF NOT <typeinfo>-idx_edit_mask IS INITIAL.
      READ TABLE lv_desc-names INDEX <typeinfo>-idx_edit_mask
        ASSIGNING <nameinfo>.
      ls_alv_fieldcat-edit_mask           = <nameinfo>-name.
      IF NOT <nameinfo>-continue IS INITIAL.
        ADD 1 TO <typeinfo>-idx_edit_mask.
        READ TABLE lv_desc-names INDEX <typeinfo>-idx_edit_mask
          ASSIGNING <nameinfo>.
        CONCATENATE
          ls_alv_fieldcat-edit_mask
          <nameinfo>-name
          INTO ls_alv_fieldcat-edit_mask.
      ENDIF." not <nameinfo>-continue IS INITIAL.
    ENDIF." not <typeinfo>-IDX_EDIT_MASK is initial.
* assign length, output length and decimals
    ls_alv_fieldcat-intlen                = <typeinfo>-length.
    ls_alv_fieldcat-outputlen             = <typeinfo>-output_length.
    ls_alv_fieldcat-decimals_out          = <typeinfo>-decimals.
    ls_alv_fieldcat-inttype               = <typeinfo>-type.
    APPEND ls_alv_fieldcat TO rt_fieldcat.
    CLEAR:  "prevent anything 2 B  taken for subsequent fields
      ls_alv_fieldcat.
  ENDLOOP." at lv_desc-types where not IDX_NAME is in initial.
ENDMETHOD.
Parameters required
    importing
      IT_TABLE type STANDARD TABLE
    returning
      value(RT_FIELDCAT) type SLIS_T_FIELDCAT_ALV .
and
method GET_ROLLNAME_4_TABFIELD .
  FIELD-SYMBOLS:
    <dfies>                               TYPE dfies.
  DATA:
    lv_tabname                            TYPE tabname,
     lt_dfies                             TYPE TABLE OF dfies,
    lv_fieldname                          TYPE fieldname.
  SPLIT iv_fieldname AT '-'
    INTO lv_tabname lv_fieldname.
  CLEAR cs_alv_fieldcat-rollname.
  CALL FUNCTION 'DDIF_FIELDINFO_GET'
    EXPORTING
      tabname                             = lv_tabname
      fieldname                           = lv_fieldname
*   LANGU                                 = SY-LANGU
*   LFIELDNAME                            = ' '
*   ALL_TYPES                             = ' '
* IMPORTING
*   X030L_WA                              =
*   DDOBJTYPE                             =
*   DFIES_WA                              =
*   LINES_DESCR                           =
   TABLES
     dfies_tab                            =  lt_dfies
*   FIXED_VALUES                          =
   EXCEPTIONS
     not_found                            = 1
     internal_error                       = 2
     OTHERS                               = 3
  IF sy-subrc                             <> 0.
    MESSAGE ID sy-msgid                   TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ELSE.
    READ TABLE   lt_dfies ASSIGNING <dfies> INDEX 1.
    cs_alv_fieldcat-rollname               = <dfies>-rollname.
* Und wenn keinerlei Twexte gepflegt sind?
    IF <dfies>-reptext IS INITIAL AND
       <dfies>-scrtext_s IS INITIAL AND
       <dfies>-scrtext_m IS INITIAL AND
       <dfies>-scrtext_l IS INITIAL.
* No Text: Use Fieldname as text
      cs_alv_fieldcat-seltext_s            =
      cs_alv_fieldcat-seltext_m            =
      cs_alv_fieldcat-seltext_l            =
      cs_alv_fieldcat-reptext_ddic         =
        cs_alv_fieldcat-fieldname.
    ENDIF." <dfies>-reptext IS INITIAL AND
  ENDIF.
endmethod.
parameters required
    importing
      IV_FIELDNAME type DYNFNAM
    changing
      value(CS_ALV_FIELDCAT) type SLIS_FIELDCAT_ALV .
Put this into class Z_CL_UTIL using SE80 and generate field catalog dynamically using statement
lt_fieldcat = Z_CL_UTIL=>fieldcat_alv( itab ).
If you have any difficulties with implementation, let me know.
Regards,
Clemens Li