What code should be written to display the second field in the selection screen when the first field is filled, and in which event should this code be written?

Question

Accepted Answer

Use AT SELECTION-SCREEN OUTPUT event to display second field based on first field input.

Use AT SELECTION-SCREEN OUTPUT event to check if first field is filled.
If first field is filled, display the second field using the statement 'SET PF-STATUS'.
Example: AT SELECTION-SCREEN OUTPUT. IF sy-abcde = 'X'. SET PF-STATUS 'SECOND_FIELD'. ENDIF.

Accepted Answer

In ABAP, you can achieve the dynamic display of selection screen fields using the AT SELECTION-SCREEN event. Here's a step-by-step guide on how to do it:

Define the Selection Screen Fields: Create the two selection screen fields.
Implement the Logic in the AT SELECTION-SCREEN Event: Write the logic to display the second field based on the value of the first field.
Here's an example code snippet to illustrate this:

abap
Copy code
REPORT zexample.

" Define the selection screen fields
PARAMETERS: p_field1 TYPE char10.
PARAMETERS: p_field2 TYPE char10.

INITIALIZATION.
  " Hide the second field initially
  LOOP AT SCREEN.
    IF screen-name = 'P_FIELD2'.
      screen-active = 0.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.

AT SELECTION-SCREEN OUTPUT.
  " Display or hide the second field based on the value of the first field
  LOOP AT SCREEN.
    IF screen-name = 'P_FIELD2'.
      IF p_field1 IS NOT INITIAL.
        screen-active = 1.
      ELSE.
        screen-active = 0.
      ENDIF.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.
Explanation:
INITIALIZATION Event: The INITIALIZATION event is used to hide the second field initially. This ensures that the second field is not visible when the selection screen is first displayed.

AT SELECTION-SCREEN OUTPUT Event: This event is used to dynamically control the display of the second field based on the value entered in the first field. If the first field (p_field1) is filled, the second field (p_field2) is displayed. If the first field is empty, the second field remains hidden.

Steps in the Code:
PARAMETERS: Define the two parameters (p_field1 and p_field2) on the selection screen.

INITIALIZATION: Loop through the screen elements and set the screen-active attribute of the second field (P_FIELD2) to 0 (inactive).

AT SELECTION-SCREEN OUTPUT: Loop through the screen elements and check if the first field (p_field1) has a value. If it does, set the screen-active attribute of the second field (P_FIELD2) to 1 (active). Otherwise, set it to 0 (inactive).

This approach ensures that the second field is only displayed when the first field is filled.