cdk_traverse(3)cdk_traverse(3)NAMEcdk_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 refer‐
enced 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/pre‐
vious widget (not counting menu widgets). Call the focusOb‐
ject 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 with‐
out 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 ALSOcdk(3), cdk_binding(3), cdk_display(3), cdk_screen(3)cdk_traverse(3)
