cdk_traverse(3) 					     Library Functions Manual						   cdk_traverse(3)

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 call-
       er 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.   Oth-
	    erwise, 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 but-
	  ton 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)