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NAME

       cdk_traverse - functions to support keyboard traversal

SYNOPSIS

       cc [ flag ... ] file ...  -lcdk [ library ... ]

       #include <cdk.h>

       CDKOBJS *getCDKFocusCurrent (CDKSCREEN *screen);

       CDKOBJS *setCDKFocusCurrent (CDKSCREEN *screen, CDKOBJS *obj);

       CDKOBJS *setCDKFocusFirst (CDKSCREEN *screen);

       CDKOBJS *setCDKFocusLast (CDKSCREEN *screen);

       CDKOBJS *setCDKFocusNext (CDKSCREEN *screen);

       CDKOBJS *setCDKFocusPrevious (CDKSCREEN *screen);

       int traverseCDKScreen (CDKSCREEN *screen);

       void exitOKCDKScreen (CDKSCREEN *screen);

       void exitCancelCDKScreen (CDKSCREEN *screen);

       void resetCDKScreen (CDKSCREEN *screen);

       void exitOKCDKScreenOf(CDKOBJS *obj);

       void exitCancelCDKScreenOf (CDKOBJS *obj);

       void resetCDKScreenOf (CDKOBJS *obj);

       void traverseCDKOnce (
                      CDKSCREEN *screen,
                      CDKOBJS *curobj,
                      int keyCode,
                      boolean functionKey,
                      CHECK_KEYCODE funcMenuKey);

DESCRIPTION

       The  functions  above  handle  the traversal of a screen populated with
       various widgets.  Once the screen has been created and  populated  with
       widgets,  a  single  call to traverseCDKScreen() will allow the user to
       move between widgets and enter data (or otherwise manipulate  widgets).
       Other functions are provided for use as callbacks by the widgets on the
       screen.  Finally, there are several functions which allow the caller to
       manipulate  the  state  of  the  traversal,  i.e., the object which has
       focus.

       In order for widgets to be used on a screen which is to be  handled  by
       traverseCDKScreen(), it must have the following methods available:
          injectCharObj
          inputWindowObj
          focusObj
          unfocusObj
          saveDataObj
          refreshDataObj

       In addition, the following object properties must be properly handled:
          acceptsFocus
          hasFocus
          inputWindow
          dataPtr
          dataType

       At the time of this writing, not all widgets have been modified to work
       with the screen-traversal facility.

AVAILABLE FUNCTIONS

       int traverseCDKScreen (CDKSCREEN *screen);
          This function contains the main screen traversal  engine.   It  does
          the following:

           1. Calls the refreshData method on each of the widgets to tell them
              to  update  their  appearance  to  match  the  data  which   are
              referenced by their respective data pointers.

           2. Calls the focusObject method on the first widget.

           3. Repeats  the  following  until  one of the exit functions listed
              above has been called:

              *  Read a keystroke from the keyboard.

              *  If the keystroke is ESCAPE and  a  menu  widget  is  present,
                 activate  the  menu and traverse it until the user selects an
                 entry or hits TAB.

              *  If the keystroke is TAB/BACKTAB then call  the  unfocusObject
                 method   on  the  current  widget,  and  move  focus  to  the
                 next/previous widget (not counting menu widgets).   Call  the
                 focusObject method on the newly current widget.

              *  If  the  keystroke  is the EXIT-SAVE keystroke, then call the
                 saveData method on each widget and return 1.

              *  If the keystroke  is  the  EXIT-CANCEL  keystroke,  return  0
                 without saving changes made by the user.

              *  If  the  keystroke is the RESET-DATA keystroke, then call the
                 refreshData method on each of  the  widgets  to  reset  their
                 appearance  to  match  the data values that were present upon
                 entry.

              *  Otherwise, pass the keystroke to the current widget.

       CDKOBJS *getCDKFocusCurrent (CDKSCREEN *screen);
            Return a pointer to the object which currently has  focus  in  the
            given screen.

       CDKOBJS *setCDKFocusCurrent (CDKSCREEN *screen, CDKOBJS *obj);
            Set  the  focus  to  the given object, if the screen contains that
            object.  If the screen does not contain the object,  return  null.
            Otherwise, return the object.

       CDKOBJS *setCDKFocusFirst (CDKSCREEN *screen);
            Set focus on the first object in the given screen.

       CDKOBJS *setCDKFocusLast (CDKSCREEN *screen);
            Set focus on the last object in the given screen.

       CDKOBJS *setCDKFocusNext (CDKSCREEN *screen);
            Set focus on the next object in the given screen.

       CDKOBJS *setCDKFocusPrevious (CDKSCREEN *screen);
            Set focus on the previous object in the given screen.

       exitOKCDKScreen
          Causes  the  traversal  engine  to  exit  after calling the saveData
          method for each of the widgets.

       exitOKCDKScreenOf
          Calls exitOKCDKScreen() on the screen associated  with  widget  obj.
          This  function  was  designed to be used as a callback routine for a
          button widget used as an OK button on a data-entry screen.

       exitCancelCDKScreen
          Causes the traversal engine to exit  without  saving  user  modified
          data.

       exitCancelCDKScreenOf
          Calls  exitCancelCDKScreen()  on  the  screen associated with widget
          obj.  This function was designed to be used as  a  callback  routine
          for a button widget used as a Cancel button on a data-entry screen.

       resetCDKScreen
          Causes  the traversal engine to call the refreshData method for each
          widget.  This will cause any unsaved changes to be discarded and the
          widget states will be restored to their initial values.

       resetCDKScreenOf
          Calls  resetCDKScreen()  on  the  screen associated with widget obj.
          This function was designed to be used as a callback  routine  for  a
          button widget used as a Reset button on a data-entry screen.

       traverseCDKOnce
          This  is  a  utility  function, one of the pieces from which you can
          construct a customized version of traverseCDKScreen.

BUGS

       Not all widgets have had the extra methods added so that they work with
       the screen traversal engine.

AUTHOR

       Grant Edwards, Aspen Research Corporation
       Thomas Dickey and contributors.

SEE ALSO

       cdk(3), cdk_binding(3), cdk_display(3), cdk_screen(3)

                                                               cdk_traverse(3)



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