FOCUS system handle


FOCUS [ :`attribute` ]

The specific attributes available depend on the type of the widget. You can determine the widget type by examining the FOCUS:TYPE attribute.

The following example uses the FOCUS handle to provide helpful information to the user. The procedure displays an interface that contains several different types of widgets. If you type ?, the procedure displays a message specifying the type of widget that has focus and whether VALUE-CHANGED event is a valid event for that widget.

r-focus.p
DEFINE VARIABLE inv-price LIKE item.price NO-UNDO. DEFINE VARIABLE inv-value LIKE item.price NO-UNDO. DEFINE VARIABLE report-type AS INTEGER NO-UNDO INITIAL 1. DEFINE BUTTON ok-butt LABEL "OK" AUTO-GO. DEFINE BUTTON cancel-butt LABEL "CANCEL" AUTO-ENDKEY. FORM inv-price LABEL "Price" AT ROW 1.25 COLUMN 2 report-type LABEL "Report Sorted ..." AT ROW 2.25 COLUMN 2 VIEW-AS RADIO-SET RADIO-BUTTONS "By Catalog Page", 1, "By Inventory Value", 2 SKIP ok-butt cancel-butt WITH FRAME select-frame SIDE-LABELS. ON ? ANYWHERE DO: MESSAGE "This is a" FOCUS:TYPE + ". VALUE-CHANGED is" (IF VALID-EVENT(FOCUS, "VALUE-CHANGED") THEN "a" ELSE "NOT a") "valid event for this widget." VIEW-AS ALERT-BOX INFORMATION BUTTONS OK. RETURN NO-APPLY. END. ENABLE ALL WITH FRAME select-frame. WAIT-FOR WINDOW-CLOSE OF CURRENT-WINDOW.

r-focus.p

DEFINE VARIABLE inv-price   LIKE item.price NO-UNDO. 
DEFINE VARIABLE inv-value   LIKE item.price NO-UNDO. 
DEFINE VARIABLE report-type AS INTEGER      NO-UNDO INITIAL 1. 
DEFINE BUTTON ok-butt     LABEL "OK" AUTO-GO. 
DEFINE BUTTON cancel-butt LABEL "CANCEL" AUTO-ENDKEY. 
       
FORM 
  inv-price LABEL "Price" AT ROW 1.25 COLUMN 2 
  report-type LABEL "Report Sorted ..." AT ROW 2.25 COLUMN 2  
    VIEW-AS RADIO-SET  
      RADIO-BUTTONS "By Catalog Page", 1, "By Inventory Value", 2 SKIP 
  ok-butt cancel-butt 
  WITH FRAME select-frame SIDE-LABELS. 
ON ? ANYWHERE DO: 
  MESSAGE "This is a" FOCUS:TYPE + ". VALUE-CHANGED is" 
    (IF VALID-EVENT(FOCUS, "VALUE-CHANGED") THEN "a" ELSE "NOT a") 
    "valid event for this widget." 
    VIEW-AS ALERT-BOX INFORMATION BUTTONS OK. 
  RETURN NO-APPLY.   
END. 
ENABLE ALL WITH FRAME select-frame. 
WAIT-FOR WINDOW-CLOSE OF CURRENT-WINDOW.

Note that this example prevents you from entering the question mark character (?) in any field. This does not cause a problem in r-focus.p because a question mark is not a valid input character for any field in the interface.

A typical use of the FOCUS handle identifies the widget that contains the current text selection for reference by the system clipboard. For an example of this usage, see OpenEdge Development: Programming Interfaces.

Within a WAIT-FOR statement, you can specify the field that receives initial input focus.

You must give input focus to any fill-in widget where you want to set the AUTO-ZAP attribute. For more information, see the SAX-reader object handle reference entry.