ALV GRID Using oo abap example

Question

Hi Friends,
I am new to oo abap, Can any one give me a basic example how i can create alv grid in oo abap.
regards,
DVNS

Answer 1

HI,
Programming for ALV grid display using the classes involves  creation of a screen and calling it for display.
Since there has to be a linking between the program and the screen we have created , this comes in the form of a container. We use two important classes during the programming for displaying ALV grid, CL_GUI_ALV_GRID and CL_GUI_CUSTOM_CONTAINER.
Steps To Use ALV Grid in a Program
1. Declare reference variables for,
       Container (class CL_GUI_CUSTOM_CONTAINER) and
       Grid (class CL_GUI_ALV_GRID)
Example
DATA: grid  TYPE REF TO cl_gui_alv_grid,
            custom_container  TYPE REF TO cl_gui_custom_container
2. Create Standard Screen and a container on that screen  and give a name to that container ( Use custom control button from tool bar) . This name will be used to link the container we have created on the screen with the object reference of class CL_GUI_CUSTOM_CONTAINER, which we have declared in the first step
3. Call the screen which has been created
4. Instantiate the container control and the ALV Grid Control in PBO of the screen.
Example
IF custom_container IS INITIAL.
  CREATE OBJECT custom_container
         EXPORTING
        CONTAINER_NAME = ‘MY_CONTAINER'.
CREATE OBJECT grid
       EXPORTING
       I_PARENT = custom_container.
ENDIF
5. For displaying the data, call the method set_table_for_first_display of object reference of CL_GUI_ALV_GRID.
Example
CALL METHOD grid->set_table_for_first_display
EXPORTING
I_BUFFER_ACTIVE               =
I_BYPASSING_BUFFER            =
I_CONSISTENCY_CHECK           =
I_STRUCTURE_NAME              =
IS_VARIANT                    =
I_SAVE                        =
I_DEFAULT                     =
IS_LAYOUT                     =
IS_PRINT                      =
IT_SPECIAL_GROUPS             =
IT_TOOLBAR_EXCLUDING          =
IT_HYPERLINK                  =
IT_ALV_GRAPHICS               =
IT_EXCEPT_QINFO               =
CHANGING
IT_OUTTAB                     =
IT_FIELDCATALOG               =
IT_SORT                       =
IT_FILTER                     =
EXCEPTION
INVALID_PARAMETER_COMBINATION =
PROGRAM_ERROR                 =
TOO_MANY_LINES                =
others                        =
EXPLANATION OF SOME IMPORTANT PARAMETERS.
I_BYPASSING_BUFFER & I_BUFFER_ACTIVE :
When the program is run for the first time, the fields present in the output table and their positions are stored in a buffer.  So the buffer is taken as reference for the successive executions.  In order to bypass this buffer the above parameter values should be ‘X’ and  ‘ ‘(space)  respectively. If these values are not passed  to the function module, the changes made in the structure of the internal table will not be reflected in the output.
I_STRUCTURE_NAME:
If the structure of your output table corresponds to a structure stored in the Data Dictionary (DDIC), the ALV Grid Control can use this information to generate the field catalog automatically. Pass the table structure as parameter. In this case, all fields of this DDIC structure are displayed in the list.
IS_VARIANT :
It allows the user to save and reuse the layout. It is a structure of type DISVARIANT and contain the display variant name. It  facilitates pre-assignment for a layout, rather than displaying report and then choosing displaying variant.
I_SAVE:
This single character variable specifies whether the user specific display variants can be saved or not.
The I_SAVE "Options for saving layouts" parameter can have the following values:
U Only user specific layouts can be saved
X Only global layouts can be saved
A Both user specific and global layouts can be saved
Space Layouts can not be saved
IS_LAYOUT:
This structure of type LVC_S_LAYO
is used to control the layout of the ALV.  Two important fields are:
GRID TITLE. : Title of grid
ZEBRA : Alternate lines in list are displayed in different colors.
IT_FIELDCATALOG:
This internal table of type LVC_T_FCAT
is used to specify the position of various fields in the report itab.
There are three ways we can fill the field catalog table
1. Automatically through data dictionary structure (DDIC). In this case we pass the table structure to I_STRUCTURE_NAME.
2. Manually in ABAP program. Filling the internal table of type LVC_T_FCAT
1.                  . With each row corresponding to each column of output table. Each row of this table will hold value like
i). TABNAME & FIELDNAME specifies the reference fields for F1 help
ii). CTABNAME & CFIELDNAME specifies the reference fields for currency formatting
iii). QTABNAME & QFIELDNAME specifies the reference fields for quantity formatting
iv). SELTEXT_L holds the long description of the field
v).  SELTEXT_M holds the medium description of the field
vi). SELTEXT_S holds the small description of the field
vii). KEY specifies the Key field ( cannot be hidden )
viii). OUTPUTLEN species the output length of the field
ix). DO_SUM specifies that subtotal is required on this field
x). NO_OUT specifies a hidden field
3.  Semi-Automatically by combining the above 2 procedures.
Call function Module REUSE_ALV_FIELDCATALOG_MERGE and pass DDIC
structure or the output table to generate the field catalog.
Add additional Rows or modify existing properties of the fields to be displayed.
METHODS OF IMPLEMENTING SOME EXTRA FEATURES
Set focus to the grid
After CALL METHODgrid->set_table_for_first_display insert the following stament:
CALL METHOD cl_gui_control=>set_focus EXPORTING control = grid
Refresh grid display
Use the grid method REFRESH_TABLE_DISPLAY
Example:
CALL METHOD grid->refresh_table_display.
Set the title of the grid
Fill the grid_title field of structure lvc_s_layo.
DATA:
gs_layout TYPE lvc_s_layo.
gs_layout-grid_title = 'TITLE'.
CALL METHOD go_grid->set_table_for_first_display
EXPORTING i_structure_name = 'structure name'
is_layout               = gs_layout
CHANGING   it_outtab               = Output table.
The structure lvc_s_layo contains fields for setting graphical properties, displaying exceptions, calculating totals and enabling specific interaction options
Event Handling
We can handle the events triggered by
1. User defined Text Output
2. Mouse-controlled Actions
3. Self-defined and Standard Functions
Steps for Event Handling
1. Define a (local) class for event handling
2. Define a method for each event you need to handle
3. Implement your event handler methods.
4. Create Object of the above class
5. Link used events and event handler methods of the  receiver object and the grid
object.
Example program : Handling “Double Click” Event
Step1.Define a class.
class lcl_my_event_receiver definition.
public section.
methods:
handle_double_click
for event double_click of cl_gui_alv_grid.
endclass.
Step 2. Implement the class
class lcl_my_event_receiver implementation.
method handle_double_click.
message i001(zz) with ' double click event - Triggerd '.
endmethod.
endclass.
Step 3. Declare and create Object for the local class defined and implemented in steps 1 and 2 respectively
o_receiver   TYPE REF TO lcl_my_event_receiver   (Declaration)
create object o_receiver.                                            (Instantiation)
Step 4. Link the method for handling the event with the grid object in the PBO of screen after instantiating the grid object
set handler o_receiver->handle_double_click for grid.
EXAMPLE PROGRAM TO CHANGE A CLASSICAL REPORT OUTPUT TO A ALV GRID
This can be used as a template program to convert a classical report layout to a ALV grid.
Report<Report name>
Grid data Declarations----------------------------------------------*
  INCLUDE ZVINALVD.
Internal table for ALV grid
TYPES: BEGIN OF T_ALV,
         Field1 like table-field1,
         Field2 like table-field2,
       END OF T_ALV.
DATA: I_ALV  TYPE TABLE OF T_ALV.
DATA: WA_ALV TYPE T_ALV.
-Class declarations----
  INCLUDE ZVINALVE.
Add a checkbox in selection screen for ALV grid display. If it is unchecked
output will be of classical type.
SELECTION-SCREEN BEGIN OF BLOCK box01.
SELECTION-SCREEN: BEGIN OF LINE.                           
SELECTION-SCREEN: COMMENT 4(30) ‘To display repot output as a ALV grid’.                  
PARAMETERS: p_alv AS CHECKBOX.                             
SELECTION-SCREEN: END OF LINE.                             
SELECTION-SCREEN END OF BLOCK box01.
START-OF-SELECTION.
Fill the ALV grid internal table
END-OF-SELECTION.
IF P_ALV = ‘X’.
  PERFORM ALV_DISPLAY.
ELSE.
  PERFORM CLASSICAL_DISPLAY.
ENDIF.
Alv Display
FORM ALV_DISPLAY.
  CALL SCREEN 100.
ENDFORM.
Module  STATUS_0100  OUTPUT
PBO for ALV Grid
MODULE STATUS_0100 OUTPUT.
  SET PF-STATUS 'GRID_DISPLAY'.
  DATA:
For parameter IS_VARIANT that is used to set up options for storing
the grid layout as a variant in method set_table_for_first_display
  l_layout TYPE disvariant.
  GS_LAYOUT-SEL_MODE = 'B'.
Optimize column width
  GS_LAYOUT-CWIDTH_OPT = 'X'.
Read data and create objects
  IF go_custom_container IS INITIAL.
Create objects for container and ALV grid
    CREATE OBJECT go_custom_container
      EXPORTING container_name = 'ALV_CONTAINER'.
    CREATE OBJECT go_grid
      EXPORTING i_parent = go_custom_container.
Create object for event_receiver class
and set handlers
    CREATE OBJECT o_event_receiver.
    SET HANDLER o_event_receiver->handle_user_command FOR go_grid.
    SET HANDLER o_event_receiver->handle_toolbar FOR go_grid.
Layout (Variant) for ALV grid
    l_layout-report = sy-repid. "Layout to report
To built fieldcatalog
    PERFORM alv_build_fieldcatalog.
Grid setup for first display
    CALL METHOD go_grid->set_table_for_first_display
      EXPORTING
                is_variant      = l_layout
                i_save          = 'A'
                is_layout       = gs_layout
      CHANGING  it_outtab       = I_ALV
                it_fieldcatalog = fieldcat.
Raise event toolbar to show the modified toolbar
    CALL METHOD go_grid->set_toolbar_interactive.
  ENDIF.
ENDMODULE.                 " STATUS_0100  OUTPUT
Form ALV_BUILD_FIELDCATALOG.
Store contents of selected line in a internal table
FORM alv_build_fieldcatalog.
  CLEAR afield.
  afield-fieldname = 'FIELD1'.
  afield-tabname   = 'I_ALV'.
  afield-coltext   = ‘Field Name 1’.
  afield-lzero     = ' '.
  afield-key       = 'X'.
  afield-outputlen =  XX.
  APPEND afield TO fieldcat.
  CLEAR afield.
  afield-fieldname = 'FIELD2'.
  afield-tabname   = 'I_ALV'.
  afield-coltext   = ‘Field Name 2’.
  APPEND afield TO fieldcat.
ENDFORM.                    " alv_build_fieldcatalog
Module  USER_COMMAND_0100  INPUT
PAI for ALV Grid
MODULE USER_COMMAND_0100 INPUT.
  CASE OK_100.
    WHEN 'BACK'.
      LEAVE TO SCREEN 0.
    WHEN 'EXIT'.
      LEAVE PROGRAM.
  ENDCASE.
ENDMODULE.                 " USER_COMMAND_0100  INPUT
Form  SELECT_LINE
Store contents of selected line in a internal table
FORM SELECT_LINE.
  DATA:l_lines TYPE i.
  REFRESH gi_index_rows.
  CLEAR   g_selected_row.
Read index of selected rows
  CALL METHOD go_grid->get_selected_rows
    IMPORTING et_index_rows = gi_index_rows.
Check if any row are selected at all. If not
table  gi_index_rows will be empty
  DESCRIBE TABLE gi_index_rows LINES l_lines.
  IF l_lines = 0.
    CALL FUNCTION 'POPUP_TO_DISPLAY_TEXT'
         EXPORTING
              textline1 = 'You must choose a line'.
    EXIT.
  ENDIF.
Read indexes of selected rows.
  LOOP AT gi_index_rows INTO g_selected_row.
    IF sy-tabix = 1.
      READ TABLE I_ALV INDEX g_selected_row-index INTO
                     WA_ALV.
    ENDIF.
  ENDLOOP.
ENDFORM.                    " SELECT_LINE
Includes:
1. ZVINALVD for data declarations
INCLUDE ZVINALVD .
Type pool for icons - used in the toolbar
TYPE-POOLS: icon.
To allow the declaration of o_event_receiver before the
lcl_event_receiver class is defined, decale it as deferred in the
start of the program
CLASS lcl_event_receiver DEFINITION DEFERRED.
GLOBAL DATA FOR ALV GRID
DATA:
OK code for alv grid screen
  OK_100(4)           TYPE C,
ALV control: Layout structure
  gs_layout           TYPE   lvc_s_layo,
Declare reference variables to the ALV grid and the container
  go_grid             TYPE REF TO cl_gui_alv_grid,
  go_custom_container TYPE REF TO cl_gui_custom_container,
  o_event_receiver    TYPE REF TO lcl_event_receiver,
Data for storing information about selected rows in the grid
Internal table
  gi_index_rows       TYPE lvc_t_row,
Information about 1 row
  g_selected_row      LIKE lvc_s_row.
fieldcatalog
DATA: fieldcat        TYPE LVC_T_FCAT,
      afield          TYPE LVC_S_FCAT.
2. ZVINALVE for Class/object declarations
INCLUDE ZVINALVE.
C L A S S E S
CLASS lcl_event_receiver DEFINITION.
  PUBLIC SECTION.
    METHODS:
      handle_toolbar FOR EVENT toolbar OF cl_gui_alv_grid
        IMPORTING e_object e_interactive,
      handle_user_command FOR EVENT user_command OF cl_gui_alv_grid
        IMPORTING e_ucomm.
ENDCLASS.
CLASS lcl_event_receiver IMPLEMENTATION
CLASS lcl_event_receiver IMPLEMENTATION.
  METHOD handle_toolbar.
Event handler method for event toolbar.
    CONSTANTS:
Constants for button type
        c_button_normal           TYPE i VALUE 0,
        c_menu_and_default_button TYPE i VALUE 1,
        c_menu                    TYPE i VALUE 2,
        c_separator               TYPE i VALUE 3,
        c_radio_button            TYPE i VALUE 4,
        c_checkbox                TYPE i VALUE 5,
        c_menu_entry              TYPE i VALUE 6.
    DATA: ls_toolbar              TYPE stb_button.
Append seperator to the normal toolbar
    CLEAR ls_toolbar.
    MOVE c_separator TO ls_toolbar-butn_type..
    APPEND ls_toolbar TO e_object->mt_toolbar.
Append a new button that to the toolbar. Use E_OBJECT of
event toolbar. E_OBJECT is of type CL_ALV_EVENT_TOOLBAR_SET.
This class has one attribute MT_TOOLBAR which is of table type
TTB_BUTTON. The structure is STB_BUTTON
    CLEAR ls_toolbar.
    MOVE 'DISPLAY'        TO ls_toolbar-function.
    MOVE  icon_DISPLAY    TO ls_toolbar-icon.
    MOVE 'Displaying customer' TO ls_toolbar-quickinfo.
    MOVE 'Display'        TO ls_toolbar-text.
    MOVE ' '             TO ls_toolbar-disabled.
    APPEND ls_toolbar    TO e_object->mt_toolbar.
  ENDMETHOD.
  METHOD handle_user_command.
Handle own functions defined in the toolbar
    CASE e_ucomm.
      WHEN 'DISPLAY'.
        PERFORM SELECT_LINE.
    ENDCASE.
ENDMETHOD.
Reward if useful