How to modify page without clicking on Execute?

Question

Hi.
I have 2 radio buttons(YES and NO) and one text field parameter(Request Number).
I want that if I click on YES, the field-active for field Request Number should become 1, and similarly
when I click on NO, the field-active should become 0.
I have used the following code:
SELECTION-SCREEN OUTPUT.
  IF p_no = 'X' .
    LOOP AT SCREEN.
      IF screen-name = 'P_TREQ'.
        screen-input = 0 .
     MODIFY SCREEN.
      ENDIF.
    ENDLOOP.
  ELSE.
    LOOP AT SCREEN.
      IF screen-name = 'P_TREQ'.
        screen-input = 1.
      ENDIF.
      MODIFY SCREEN.
    ENDLOOP.
  ENDIF.
I have to click on execute everytime I'm switching the  radio buttons.
I dont want that.
Help me here.

Answer 1

REPORT  zzbc_bha_test.
DATA uc LIKE sy-ucomm.
SELECTION-SCREEN BEGIN OF BLOCK b1 WITH FRAME.
PARAMETERS: p_no RADIOBUTTON GROUP rb USER-COMMAND uc,
             p_no1 RADIOBUTTON GROUP rb DEFAULT 'X',
             p_text LIKE mara-matnr.
SELECTION-SCREEN END OF BLOCK b1.
AT SELECTION-SCREEN OUTPUT.
   IF p_no EQ 'X'.
     LOOP AT SCREEN.
       IF screen-name = 'P_TEXT'.
         screen-input = 0.
         screen-active = 0.
         MODIFY SCREEN.
       ENDIF.  "IF screen-name = 'P_TEXT'.
     ENDLOOP.
   ELSE.
     LOOP AT SCREEN.
       IF screen-name = 'P_TEXT'.
         screen-input = 1.
         screen-active = 1.
         MODIFY SCREEN.
       ENDIF.  "IF screen-name = 'P_TEXT'.
     ENDLOOP.
   ENDIF.  "IF uc EQ p_no.