Alv using OO

Question

Hi,
I'm trying out ALV using OO approach. Im building a very basic alv, However the alv is not displaying anything. Can any one tell me where is the bug ?
Here is my code
REPORT  ztest.
TYPES:BEGIN OF REC,
        A(30),
      END OF REC.
*--- ALV Grid instance reference
DATA gr_alvgrid TYPE REF TO cl_gui_alv_grid .
*--- Name of the custom control added on the screen
DATA gc_custom_control_name TYPE scrfname." VALUE u2018cc_alvu2019 .
*--- Custom container instance reference
DATA gr_ccontainer TYPE REF TO cl_gui_custom_container .
*--- Field catalog table
DATA gt_fieldcat TYPE lvc_t_fcat .
*--- Layout structure
DATA gs_layout TYPE lvc_s_layo .
DATA: int_tab TYPE STANDARD TABLE OF rec WITH HEADER LINE.
BREAK-POINT.
PERFORM populate_data.
IF gr_ccontainer IS INITIAL.
  CREATE OBJECT gr_ccontainer
    EXPORTING
      container_name              = 'CC_ALV'
    EXCEPTIONS
      cntl_error                  = 1
      cntl_system_error           = 2
      create_error                = 3
      lifetime_error              = 4
      lifetime_dynpro_dynpro_link = 5
      OTHERS                      = 6.
  CREATE OBJECT gr_alvgrid
    EXPORTING
      i_parent          = gr_ccontainer
    EXCEPTIONS
      error_cntl_create = 1
      error_cntl_init   = 2
      error_cntl_link   = 3
      error_dp_create   = 4
      OTHERS            = 5.
  CALL METHOD gr_alvgrid->set_table_for_first_display
   EXPORTING
    I_STRUCTURE_NAME = 'REC'
     is_layout = gs_layout
      CHANGING
      it_outtab = int_tab[]
      it_fieldcatalog = gt_fieldcat[]
    EXCEPTIONS
      invalid_parameter_combination = 1
      program_error = 2
      too_many_lines = 3
      OTHERS = 4 .
      SY-SUBRC = SY-SUBRC.
ELSE.
  CALL METHOD gr_alvgrid->refresh_table_display
  EXCEPTIONS
  finished = 1
  OTHERS = 2 .
      SY-SUBRC = SY-SUBRC.
ENDIF.
*&      Form  populate_data
      text
FORM populate_data.
  DATA ls_fcat TYPE lvc_s_fcat .
  INT_TAB-A = 'HI'.
  APPEND INT_TAB.
  INT_TAB-A = 'HELLO'.
  APPEND INT_TAB.
  ls_fcat-tabname = 'INT_TAB'.
  ls_fcat-fieldname = 'A' .
  LS_FCAT-COL_POS = 1.
  ls_fcat-inttype = 'C' .
  ls_fcat-outputlen = '30' .
  ls_fcat-coltext = 'test' .
  ls_fcat-seltext = 'TEST' .
  APPEND ls_fcat TO gt_fieldcat .
  clear ls_fcat.
ENDFORM.                    "populate_data

Answer 1

Hi,
You are not calling the screen in your program where you have placed your custom container. Hence it is displaying nothing.
Also the place where you are instanciating the objects is not correct.
Jus check the program BCALV_GRID_02 for correctly creating a list using OO approach.
Cheers,
Hakim