At last I have find time to write this 🙂 . If you find anything wrong pls let me know.

As all you know screen process in ABAP has two main block PBO ( Process before output ) and PAI ( Process after input ). All screen has this block.

For dialog program I used this.

So we can declare a parent screen object for all screen which we use in program.

Definition:

CLASS lcl_screen DEFINITION ABSTRACT.
   PUBLIC SECTION.
METHODS : constructor
                IMPORTING
                  i_dynnr TYPE sy-dynnr.
 * All screen process
     METHODS : pbo ABSTRACT,
               pai ABSTRACT
                IMPORTING
                  fcode TYPE sy-ucomm
                RETURNING value(r_fcode) TYPE sy-ucomm,
               free ABSTRACT.
 * Exit-command
     METHODS : exit_command
                IMPORTING
                  fcode TYPE sy-ucomm.
 * Screen static methods
     CLASS-METHODS : get_screen
                      IMPORTING
                        i_dynnr TYPE sy-dynnr
                      RETURNING value(r_screen) TYPE REF TO lcl_screen.
     CLASS-METHODS : del_screen
                      IMPORTING
                        i_dynnr TYPE sy-dynnr.
PRIVATE SECTION.
     DATA : screen TYPE sy-dynnr.
     TYPES : BEGIN OF lst_screen,
              screen TYPE REF TO lcl_screen,
             END OF lst_screen.
     CLASS-DATA : t_screen TYPE STANDARD TABLE OF lst_screen.
     CONSTANTS : c_class_name TYPE string VALUE 'LCL_SCREEN'.
ENDCLASS.                    "lcl_screen DEFINITION

Implementation

CLASS lcl_screen IMPLEMENTATION.
   METHOD constructor.
     screen = i_dynnr."Which screen
   ENDMETHOD.                    "constructor
   METHOD exit_command.
     CASE fcode.
       WHEN 'EXIT'.
         LEAVE PROGRAM.
     ENDCASE.
   ENDMETHOD.                    "exit_command
   METHOD get_screen.
     DATA : ls_screen TYPE lst_screen,
            lv_type TYPE string.
     READ TABLE t_screen
           INTO ls_screen
       WITH KEY screen->screen = i_dynnr.
     IF sy-subrc NE 0.
       CONCATENATE c_class_name
                   i_dynnr
              INTO lv_type
         SEPARATED BY '_'.
       CREATE OBJECT ls_screen-screen TYPE (lv_type)
         EXPORTING
           i_dynnr = i_dynnr.
       APPEND ls_screen
           TO t_screen.
     ENDIF.
     r_screen ?= ls_screen-screen.
   ENDMETHOD.                    "get_screen
   METHOD del_screen.
     DATA : ls_screen TYPE lst_screen,
            lv_type TYPE string.
     READ TABLE t_screen
           INTO ls_screen
       WITH KEY screen->screen = i_dynnr.
     IF sy-subrc NE 0.
 * Screen doesnt exist
       RETURN.
     ENDIF.
     ls_screen-screen->free( ).
     DELETE t_screen
      WHERE screen->screen = i_dynnr.
   ENDMETHOD.                    "del_screen
ENDCLASS.                    "lcl_screen IMPLEMENTATION

In get_screen method, to decide which screen object will be created, logic is all screen object start with LCL_SCREEN_ and last 4 character is screen number. If screen object is not created, we create object and adding it to object table then returning screen object. If it is created just returning the object.

lets create our first screen :

And screen module is:

 MODULE pbo OUTPUT.
   lcl_screen=>get_screen( sy-dynnr )->pbo( ).
 ENDMODULE.                 " PBO  OUTPUT
MODULE pai INPUT.
   gv_okcode = lcl_screen=>get_screen( sy-dynnr )->pai( gv_okcode ).
 ENDMODULE.                 " PAI  INPUT
MODULE exit_command INPUT.
   lcl_screen=>get_screen( sy-dynnr )->exit_command( gv_okcode ).
 ENDMODULE.                 " EXIT_COMMAND  INPUT

Now lets create screen 9000 object

Definition

CLASS lcl_screen_9000 DEFINITION INHERITING FROM lcl_screen FINAL.
   PUBLIC SECTION.
     METHODS : pbo REDEFINITION,
               pai REDEFINITION,
               free REDEFINITION.
   PRIVATE SECTION.
 * Screen 9000 methods
     METHODS : set_exclude
                RETURNING value(rt_ex) TYPE status_excl_fcode_tt.
 ENDCLASS.                    "lcl_screen_9000 DEFINITION

Implementation

CLASS lcl_screen_9000 IMPLEMENTATION.
   METHOD pbo.
     DATA : lt_ex TYPE status_excl_fcode_tt.
     lt_ex = set_exclude( ).
     SET PF-STATUS 'STATUS_9000' EXCLUDING lt_ex.
     SET TITLEBAR '9000'.
   ENDMETHOD.                    "pbo
   METHOD set_exclude.
     DATA : lv_ex TYPE fcode.
     lv_ex = 'SAVE'.
     APPEND lv_ex
         TO rt_ex.
   ENDMETHOD.                    "set_exclude
   METHOD pai.
     CASE fcode.
       WHEN 'BACK'.
           LEAVE TO SCREEN 0.
     ENDCASE.
   ENDMETHOD.                    "pai
   METHOD free.
 * If we declare global object data, we can clear or refresh here!
   ENDMETHOD.                    "free
 ENDCLASS.                    "lcl_screen_9000 IMPLEMENTATION

As you can see screen releated methods can be declare in screen object.

like set_exclude method.

If a method is global for all screen we can add to lcl_screen for example POPUP_TO_CONFIRM function. we can add this method to lcl_screen

TYPES : ty_text(400) TYPE c.
     METHODS : call_popup
                IMPORTING
                  i_title TYPE text60
                  i_text  TYPE ty_text
                RETURNING value(r_answer) TYPE char1.

METHOD call_popup.
     CALL FUNCTION 'POPUP_TO_CONFIRM'
       EXPORTING
         titlebar       = i_title
         text_question  = i_text
       IMPORTING
         answer         = r_answer
       EXCEPTIONS
         text_not_found = 1
         OTHERS         = 2.
     IF sy-subrc <> 0.
 * Implement suitable error handling here
     ENDIF.
   ENDMETHOD.                    "call_popup

Now we can use this method in all screen.

METHOD pai.
     CASE fcode.
       WHEN 'BACK'.
IF call_popup( i_title = text-006
                           i_text  = text-007 ) EQ '1'.
           LEAVE TO SCREEN 0.
         ENDIF.
     ENDCASE.
   ENDMETHOD.                    "pai

If we need to create ALV object in one screen we can add this to screen like, or picture element. Just we need to do declare screen object inherited from lcl_screen.

I hope you like it.

Have a nice day.