Web Dynpro Application For developing a simple calculator

Question

Dear Experts,
I am trying to develop a simple calculator application in abap web dynpro .
but i am not able to enable the buttons (1 to 9) . that is what i want is like how it happens in a normal calculator if we press 1 , then in the screen, 1 comes and if 11 then twice we press 1. Like wise i want if the button 1 is enabled then in the input field it should take 1 and if 11 then it should take 11. Kindly give some suggestions to develop this application.
Regards
Swarnadeepta

Answer 1

Hi Swarnadeepta,
I developed a calculator in web dynpro...please go through the following code. I have made a few changes with respect to modularization but the basic concept is still the same.
Method to Enter Data on the screen
METHOD enter_data .
  DATA lv_input TYPE i.
  DATA lv_flag TYPE c.
***Read input in the screen 
wd_this->get_input(
    IMPORTING
      ev_input = lv_input                       " integer
***See whether flag is set. If yes save the present value in global attribute gv_previous.
  wd_this->get_flag(
    IMPORTING
      ev_flag = lv_flag                        " wdy_boolean
  IF lv_flag = 'X'.
    wd_this->gv_previous = lv_input.
    lv_input = 0.
  ENDIF.
***Modify screen input
  IF lv_input IS INITIAL.
    lv_input = iv_number.
  ELSE.
    lv_input = lv_input * 10 + iv_number.
  ENDIF.
***Set the new value of input field
  wd_this->set_input(
    iv_input = lv_input                          " integer
***Reset the flag
  wd_this->set_flag(
    iv_flag = ''                           " wdy_boolean
ENDMETHOD.
Use the above method on button click
method ONACTIONONE .
  wd_this->enter_data(
    iv_number = 1                        " integer
endmethod.
Method to Register Operations
method ENTER_OPERATION .
  wd_this->set_flag(
    iv_flag = 'X'                           " wdy_boolean
  wd_this->set_operation(
    iv_operation = iv_operation                      " string
endmethod.
Use of above method in operations button
method ONACTIONADD .
  wd_this->enter_operation(
    iv_operation = 'ADD'                     " string
endmethod.
Method to calculate
method ONACTIONEQL .
DATA lv_operation TYPE string.
DATA lv_input TYPE i.
***Read screen input 
wd_this->get_input(
     IMPORTING
       ev_input = lv_input                        " integer
***read operation requested
  wd_this->get_operation(
    IMPORTING
      ev_operation = lv_operation                   " string
CASE lv_operation.
WHEN 'ADD'.
lv_input = wd_this->gv_previous + lv_input.
WHEN 'SUB'.
lv_input = wd_this->gv_previous - lv_input.
WHEN 'MUL'.
lv_input = wd_this->gv_previous * lv_input.
WHEN 'DIV'.
lv_input = wd_this->gv_previous / lv_input.
WHEN OTHERS.
ENDCASE.
***Set the new value of input field
  wd_this->set_input(
    iv_input = lv_input                         " integer
***Clear the operation attribute
  wd_this->set_operation(
    iv_operation = ''                     " string
endmethod.
Getter Methods example for attribute INPUT
method GET_INPUT .
  DATA lo_el_context TYPE REF TO if_wd_context_element.
  DATA ls_context TYPE wd_this->element_context.
  DATA lv_input TYPE wd_this->element_context-input.
get element via lead selection
  lo_el_context = wd_context->get_element( ).
@TODO handle not set lead selection
  IF lo_el_context IS INITIAL.
  ENDIF.
get single attribute
  lo_el_context->get_attribute(
    EXPORTING
      name =  `INPUT`
    IMPORTING
      value = lv_input ).
EV_INPUT = lv_input.
endmethod.
Setter Methods example for attribute INPUT
method SET_INPUT .
  DATA lo_el_context TYPE REF TO if_wd_context_element.
  DATA ls_context TYPE wd_this->element_context.
  DATA lv_input TYPE wd_this->element_context-input.
get element via lead selection
  lo_el_context = wd_context->get_element( ).
@TODO handle not set lead selection
  IF lo_el_context IS INITIAL.
  ENDIF.
@TODO fill attribute
lv_input = iv_input.
set single attribute
  lo_el_context->set_attribute(
    name =  `INPUT`
    value = lv_input ).
endmethod.
Hope this will be helpful. Let me know if you have any doubt.
Its working fine for me.
Regards,
Sayan