BCALV_EDIT_08

program bcalv_edit_08.
*&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
* Purpose:
* ~~~~~~~~
* This report implements an ALV Grid Control with an application
* specific F4 help. The following aspects are dealth with:
* o how to replace the standard f4 help
*     NOTE: This example uses a second ALV Grid Control to
*           provide an application specific F4 help.
*           This is probalbly NOT the usual way to
*           provide such a functionality.
*           However, the purpose of this report is not to
*           show you how to implement an F4 help, but to
*           explain how you pass the selected value to ALV,
*           how you take values of other cells into account, etc.
*           For this purpose, it does not matter how the f4 help
*           is actually implemented.
*
* o how to pass the selected value to the ALV Grid Control
* o how to build an f4 help, whose value range depend on
*    a value of another cell.
*-----------------------------------------------------------------
* To check program behavior
* ~~~~~~~~~~~~~~~~~~~~~~~~~
* We use table SBOOK with columns CLASS and SMOKER ready for input.
* The idea of this scenario is that it is only allowed to smoke
* in the first class (value 'F' of field CLASS).
* The application specific f4 help can be called for column CLASS:
* o if the value of column SMOKER in the same row is 'X', only class
*   'F' can be chosen
* o if the value of column SMOKER in the same row is ' ', all
*   classes are allowed ('F','C','Y'). Thus, the f4 help shows all
*   values.
* o if the value of column SMOKER in the same row is not valid
*   (syntactically or semantically), a message is shown and
*   no f4 help pops up.
*-----------------------------------------------------------------
* Essential steps (search for '§')
* ~~~~~~~~~~~~~~~
* Note that this report is rather long because the columns CLASS and
* SMOKER are checked semantically which does not belong to the f4 help
* implementation. Class lcl_application_dc handles semantic checks.
* Local class lcl_application_f4 handles event ONF4 to build up
* the f4 help, to pass the value to the ALV Grid Control and
* to check whether the value of the SMOKER column is valid.
*
* 1. Register event ONF4 at frontend using method
*    register_f4_for_fields. For this purpose, you pass a table
*    with all fields, for which you want to implement your own
*    f4 help.
*   1b. If the value range in your f4 help depends on other
*       values of cells that are input enabled, set the
*       GETBEFORE parameter.
* 2. Implement an event handler method for event ONF4.
* 3. Call your own f4 help. To customize your popup check
*    first if the cell is ready for input (event parameter E_DISPLAY).
* 4. Check whether the value your f4 help depends on is valid.
* 5. If not already caught by your own f4 help, check whether
*    the triggered cell was ready for input by using E_DISPLAY
*    and if not, exit.
* 6. After the user selected a value, pass it to the ALV Grid Control:
*   6a. Define a field symbol of type: LVC_T_MODI and a structure of
*       type LVC_S_MODI to pass the value later on.
*   6b. Dereference attribute M_DATA to your field symbol and add
*       the selected value to the table to which this symbol points to.
* 7. Inform the ALV Grid Control that an own f4 help has been processed
*    to suppress the standard f4 help.
*-----------------------------------------------------------------------
*&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

data: ok_code like sy-ucomm,
      save_ok like sy-ucomm,
      g_container type scrfname value 'CC1',
      g_grid type ref to cl_gui_alv_grid,
      g_custom_container type ref to cl_gui_custom_container,
      gt_fieldcat type lvc_t_fcat,
       g_max type i value 100.

class lcl_application_f4 definition deferred.
class lcl_application_dc definition deferred.

data: g_onf4 type ref to lcl_application_f4,
      g_dc type ref to lcl_application_dc.

data: gt_outtab type table of sbook.

****************************************************************
* LOCAL CLASSES: Definition
****************************************************************
*===============================================================
* class lcl_application_f4: local class to handle own F4.
*
* Definition:
* ~~~~~~~~~~~
class lcl_application_f4 definition.

public section.
    methods:

             on_f4 for event onf4 of cl_gui_alv_grid
               importing e_fieldname
                         es_row_no
                         er_event_data
                         et_bad_cells
                         e_display.

    methods: reset.
    methods: show_f4.

private section.
**
* attributes for creating an own F4-Help
* (using a second ALV Grid Control
**
    data: f4_alv type ref to cl_gui_alv_grid,
          f4_cont type ref to cl_gui_custom_container.

    types: begin of f4_itab_type.
    types: value type s_class.
    types: descr(20) type c.
    types: end of f4_itab_type.

    data: f4_itab type table of f4_itab_type.
    data: fieldcatalog type lvc_t_fcat.

**
* attributes to store event parameters
* (after the CALL SCREEN command, the event parameters
* are not accessible)
**
    types: begin of onf4_event_parameters_type.
    types: c_fieldname     type lvc_fname.
    types: cs_row_no       type lvc_s_roid.
    types: cr_event_data   type ref to cl_alv_event_data.
    types: ct_bad_cells    type lvc_t_modi.
    types: c_display       type char01.
    types: end of onf4_event_parameters_type.

    data: f4_params type onf4_event_parameters_type.

**
* Methods to create own F4-Help
* (This is done using a second ALV Grid Control)
**
    methods: init_f4.

    methods: build_fieldcatalog.
    methods: fill_f4_itab importing smoker type c.

    methods: on_double_click for event double_click of cl_gui_alv_grid
                    importing es_row_no.

**
* Methods to check whether the values which the F4-Help needs
* are correct
* (The entries of the F4-Help of field CLASS depend on the value
* of field SMOKER. If field SMOKER of the same row is syntaktically
* or semantically not correct, this has to be handled during ONF4.
**
    methods: smoker_cell_is_bad
                returning value(r_flag) type i.

endclass.                    "lcl_application_f4 DEFINITION
*
* lcl_application_f4 (Definition)
*===============================================================
* class lcl_application_dc: local class to handle event data_changed.
*
* Definition:
* ~~~~~~~~~~~
class lcl_application_dc definition.

public section.

    methods: handle_data_changed
               for event data_changed of cl_gui_alv_grid
                  importing er_data_changed
                            e_onf4 e_onf4_before e_onf4_after.

private section.

* This flag is set if any error occured in one of the
* following methods:
    data: error_in_data type c.

    methods:
     perform_semantic_checks
       importing
         pr_data_changed type ref to cl_alv_changed_data_protocol.

    methods: check_smoker
     importing
        ps_good_smoker type lvc_s_modi
        pr_data_changed type ref to cl_alv_changed_data_protocol.

    methods: check_class
     importing
        ps_good_class type lvc_s_modi
        pr_data_changed type ref to cl_alv_changed_data_protocol.

endclass.                    "lcl_application_dc DEFINITION
*
* lcl_application_dc (Definition)
*===============================================================

****************************************************************
* LOCAL CLASSES: Implementation
****************************************************************
*===============================================================
* class lcl_application_f4 (Implementation)
*
class lcl_application_f4 implementation.

*§2. Implement an event handler method for event ONF4.

method on_f4.

* Save event parameter as global attributes of this class
* (maybe solved differently if you use a function module!)
    f4_params-c_fieldname = e_fieldname.
    f4_params-cs_row_no = es_row_no.
    f4_params-cr_event_data = er_event_data.
    f4_params-ct_bad_cells = et_bad_cells.
    f4_params-c_display = e_display.

*§3. Call your own f4 help. To customize your popup check
*    first if the cell is ready for input (event parameter E_DISPLAY).
* (parameter E_DISPLAY is checked later in method on_double_click)

* (Probably, you would call a function module at this point,
* pass the needed event parameter and call the popup screen
* within that function module. This is not done in this example
* to avoid scattering its code).

    call screen 101 starting at 10 10.

*§7. Inform the ALV Grid Control that an own f4 help has been processed
*    to suppress the standard f4 help.

    er_event_data->m_event_handled = 'X'.
endmethod.                                                "on_f4
*---------------------------------------------------------------------
method show_f4.
    data: ls_outtab type sbook.

* initialize own f4 help if needed
    if f4_cont is initial.
      call method init_f4.
    endif.

*§4. Check whether the value your f4 help depends on is valid.

* The possible values of field CLASS depend on
* the value of field SMOKER of the same row.
* You have to check that this value is valid:
    if smoker_cell_is_bad( ) eq 1.
      leave screen.
    endif.

* determine value of column SMOKER and use appropriate f4 table
    read table gt_outtab into ls_outtab index f4_params-cs_row_no-row_id
.
    call method fill_f4_itab( ls_outtab-smoker ).

* refresh list of values in f4 help and show it
    call method f4_alv->refresh_table_display.
* CAUTION: Do not use method REFRESH_TABLE_DISPLAY for
* your editable ALV Grid instances while handling events
* DATA_CHANGED or ONf4. You would overwrite intermediate
* values of your output table on frontend.
* 'f4_alv' is a non-editable ALV Grid Control for the
* application specific F4-Help. Therefore, calling
* REFRESH_TABLE_DISPLAY for this instance has no
* negative effect.

    call method cl_gui_cfw=>flush.
endmethod.                                                "show_f4

*--------------------------------------------------------------------

method init_f4.
    data: ls_layout type lvc_s_layo.
* build fieldcatalog entries for f4
    call method build_fieldcatalog.

* create controls
    create object f4_cont
              exporting container_name = 'CC_ONF4'.

    create object f4_alv
              exporting i_parent = f4_cont.

* hide toolbar
    ls_layout-no_toolbar = 'X'.

    call method f4_alv->set_table_for_first_display
      exporting
        is_layout       = ls_layout
      changing
        it_fieldcatalog = fieldcatalog
        it_outtab       = f4_itab.

* register event double click on backend
    set handler me->on_double_click for f4_alv.

* flush since 'ls_layout' is local!
    call method cl_gui_cfw=>flush.

endmethod.                                                "init_f4
*-----------------------------------------------------
method fill_f4_itab.
    data ls_f4_itab type f4_itab_type.

* Delete all entries in f4_itab to determine
* offered values dynamically
    clear f4_itab[].
* create entries depending on SMOKER field
    if smoker is initial.
      ls_f4_itab-value = 'C'.
      ls_f4_itab-descr = text-t03. "Business Class
      append ls_f4_itab to f4_itab.
      ls_f4_itab-value = 'Y'.
      ls_f4_itab-descr = text-t04. "Economie Class
      append ls_f4_itab to f4_itab.
      ls_f4_itab-value = 'F'.
      ls_f4_itab-descr = text-t05. "First Class
      append ls_f4_itab to f4_itab.
    else.
      ls_f4_itab-value = 'F'.
      ls_f4_itab-descr = text-t05. "First Class
      append ls_f4_itab to f4_itab.
    endif.
endmethod.                    "fill_f4_itab
*----------------------------------------------------
method build_fieldcatalog.
    data: ls_fcat type lvc_s_fcat.

    clear ls_fcat.
    ls_fcat-fieldname = 'VALUE'.
    ls_fcat-coltext = text-t02.
    ls_fcat-inttype = 'S_CLASS'.
    ls_fcat-outputlen = 5.
    append ls_fcat to fieldcatalog.
    clear ls_fcat.
    ls_fcat-fieldname = 'DESCR'.
    ls_fcat-coltext = text-t01.
    ls_fcat-inttype = 'C'.
    ls_fcat-outputlen = 20.
    append ls_fcat to fieldcatalog.
endmethod.                    "build_fieldcatalog
*-----------------------------------------------------
method on_double_click.

*§5. If not already caught by your own f4 help, check whether
*    the triggered cell was ready for input by using E_DISPLAY
*    and if not, exit.
    if f4_params-c_display eq 'X'.
      leave screen.
    endif.

*§6. After the user selected a value, pass it to the ALV Grid Control:

*§ 6a. Define a field symbol of type: LVC_T_MODI and a structure of
*       type LVC_S_MODI to pass the value later on.
    field-symbols type lvc_t_modi.
    data: ls_modi type lvc_s_modi,
          ls_f4_itab type f4_itab_type.

*§ 6b. Dereference attribute M_DATA into your field symbol and add
*       the selected value to the table to which this symbol points to.
    assign f4_params-cr_event_data->m_data->* to .
    ls_modi-row_id = f4_params-cs_row_no-row_id.
    ls_modi-fieldname = f4_params-c_fieldname.

    read table f4_itab into ls_f4_itab index es_row_no-row_id.

    ls_modi-value = ls_f4_itab-value.
    append ls_modi to .

    leave screen.
endmethod.                    "on_double_click
*-----------------------------------------------------
method reset.
    field-symbols type lvc_t_modi.

    assign f4_params-cr_event_data->m_data->* to .
    clear [].
endmethod.                    "reset
*-----------------------------------------------------
method smoker_cell_is_bad.
    data: ls_bad_cell type lvc_s_modi. "#EC NEEDED

    r_flag = 0. "no error initially

* Determine if value of smoker cell of the same
* row has a bad value. If so, a message pops up
* instead of our F4 help.
    read table f4_params-ct_bad_cells into ls_bad_cell
        with key fieldname = 'SMOKER'
                 row_id    = f4_params-cs_row_no-row_id.
    if sy-subrc eq 0.
        r_flag = 1.
        message i000(0k) with text-i01 text-i02.
* NOTE: Although there is a bad value present
*       the ALV Grid Control shows no error protocol.
*       However, the bad value is saved in the
*       protocol and event DATA_CHANGED_FINISHED is
*       not raised.
    endif.

endmethod.                    "smoker_cell_is_bad
*=====================================================

endclass.                    "lcl_application_f4 IMPLEMENTATION

*
* lcl_application_f4 (Implementation)
*===================================================================

*===============================================================
* class lcl_application_dc (Implementation)
*
class lcl_application_dc implementation.
method handle_data_changed.
*
    error_in_data = space.

* Distinguish, if DATA_CHANGED was raised because of an
* own F4-help.
* Event DATA_CHANGED provides parameter E_ONF4
* for this purpose.
    if not e_onf4 is initial.
* Add your special handling here if needed.
* Event DATA_CHANGED provides parameters E_ONF4_AFTER
* and E_ONF4_BEFORE to distinguish the context
* additionally.

* In general, semantic checks should be the same no matter if
* they have been entered by hand or using an application
* specific F4 help. So you probably do not need these parameters.
    else.
      call method perform_semantic_checks( er_data_changed ).
    endif.

    if error_in_data = 'X'.
      call method er_data_changed->display_protocol.
    endif.

endmethod.                    "handle_data_changed
*------------------------------------
* private methods
*------------------------------------
method perform_semantic_checks.
*
* In this snenario, only values of cells in columns CLASS or SMOKER
* can be changed. These fields have a value range defined
* in the ABAP dictionary.
* Thus, after ALVs syntaktical check, we only need to
* check if the user tried to enter a smoker seat for
* a class other than 'F' or vice versa.
*
    data: ls_good type lvc_s_modi.

    loop at pr_data_changed->mt_good_cells into ls_good.
      case ls_good-fieldname.
        when 'SMOKER'.
          call method check_smoker
            exporting
              ps_good_smoker = ls_good
              pr_data_changed = pr_data_changed.

        when 'CLASS'.
          call method check_class
            exporting
              ps_good_class   = ls_good
              pr_data_changed = pr_data_changed.
      endcase.
    endloop.

endmethod.                    "perform_semantic_checks
*--------------------------------------
method check_smoker.
    data: l_smoker type s_smoker,
          l_class type s_class,
          ls_outtab type sbook,
          ls_good_class type lvc_s_modi. "#EC NEEDED

* first get value of smoker cell:
    call method pr_data_changed->get_cell_value
      exporting
        i_row_id    = ps_good_smoker-row_id
        i_fieldname = ps_good_smoker-fieldname
      importing
        e_value     = l_smoker.

* If it's a non smoker there is no problem at all
* because every value of CLASS shall be possible then.
    if l_smoker is initial.
      exit.
    endif.

* If not, value of cell CLASS has to be 'F'.
* First check if the value of field CLASS has been
* changed/entered newly, too:
    read table pr_data_changed->mt_good_cells into ls_good_class
                        with key row_id    = ps_good_smoker-row_id
                                 fieldname = 'CLASS'.
    if sy-subrc eq 0.
* get that new value:
      call method pr_data_changed->get_cell_value
        exporting
          i_row_id    = ps_good_smoker-row_id
          i_fieldname = 'CLASS'
        importing
          e_value     = l_class.
    else.
* get current value
      read table gt_outtab into ls_outtab index ps_good_smoker-row_id.
      l_class = ls_outtab-class.
    endif.

* Since we have a smoker his class has to be 'F':
    if l_class ne 'F'.
      call method pr_data_changed->add_protocol_entry
        exporting
          i_msgid     = '0K'
          i_msgno     = '000'
          i_msgty     = 'E'
          i_msgv1     = text-m01           "Klasse
          i_msgv2     = l_class
          i_msgv3     = text-m02           "nicht erlaubt für Raucher
          i_fieldname = ps_good_smoker-fieldname
          i_row_id    = ps_good_smoker-row_id.

      error_in_data = 'X'.
    endif.
endmethod.                    "check_smoker
*--------------------------------------
method check_class.
      data: l_smoker type s_smoker,
            l_class type s_class,
            ls_outtab type sbook,
            ls_good_smoker type lvc_s_modi. "#EC NEEDED

* first get value of class cell:
    call method pr_data_changed->get_cell_value
      exporting
        i_row_id    = ps_good_class-row_id
        i_fieldname = ps_good_class-fieldname
      importing
        e_value     = l_class.

* If it's CLASS 'F' there is no problem at all
* because every value of SMOKER shall be possible then.
    if l_class eq 'F'.
      exit.
    endif.

* If not, value of cell SMOKER has to be initial.
* First check if the value of field CLASS has been
* changed/entered newly, too:
    read table pr_data_changed->mt_good_cells into ls_good_smoker
                        with key row_id    = ps_good_class-row_id
                                 fieldname = 'SMOKER'.
    if sy-subrc eq 0.
* get that new value:
      call method pr_data_changed->get_cell_value
        exporting
          i_row_id    = ps_good_class-row_id
          i_fieldname = 'SMOKER'
        importing
          e_value     = l_smoker.
    else.
* get current value
      read table gt_outtab into ls_outtab index ps_good_class-row_id.
      l_smoker = ls_outtab-smoker.
    endif.

* Since the class is not 'F' it has to be a non smoking person:
    if not l_smoker is initial.
      call method pr_data_changed->add_protocol_entry
        exporting
          i_msgid     = '0K'
          i_msgno     = '000'
          i_msgty     = 'W'
          i_msgv1     = text-m03         "Als Raucher dürfen Sie Klasse
          i_msgv2     = l_class
          i_msgv3     = text-m04         "nicht buchen
          i_fieldname = ps_good_class-fieldname
          i_row_id    = ps_good_class-row_id.

      error_in_data = 'X'.
    endif.

endmethod.                    "check_class