VkPrefItem(3x)

NAME
     VkPrefItem - Abstract class that supports preference items

INHERITS FROM
     VkComponent : VkCallbackObject

HEADER FILE
     #include <Vk/VkPrefItem.h>

PUBLIC PROTOCOL SUMMARY
   Access Functions
           virtual int type(void);
           virtual Boolean changed(void);
           virtual Dimension labelHeight(void);
           virtual Dimension baseHeight(void);
           virtual void setLabelHeight(Dimension height);
           virtual void setBaseHeight(Dimension height);
           Widget labelWidget(void);


   Activating/Deactivating
           virtual void activate();
           virtual void deactivate();


CLASS DESCRIPTION
          VkPrefItem is an abstract class that supports easy-to-create
          preference panels. The classes derived from VkPrefItem form a simple
          toolkit that creates preference panels, typically placed in a
          dialog.  When creating a preference pane using the VkPref classes
          one does not normally pay much attention to layout, but allows the
          VkPref classes to create a layout automatically. The VkPref classes
          provide users the ability to cancel any operation at any time,
          reverting all preferences to their previous values. Automatically.
          Programmers who use the preference classes do not have to deal with
          callbacks or data retrieval on a per-widget basis, but instead allow
          the VkPref classes to handle all intermediate states transparently.
          Applications simply look at the final values of all preferences to
          see what has changed when the user applies the preferences.

          Preference panels are organized around from the VkPrefDialog class,
          the VkPrefList class, and the VkPrefGroup class. See man pages for
          those classes for examples of how to create preference panels.



FUNCTION DESCRIPTIONS
   VkPrefItem()
           virtual void ~VkPrefItem(void);

          The VkPrefItem destructor destroys the companion label widget, and
          frees strings created for the base and label widget names.

   type()
           virtual int type(void);


          The type method is overridden by subclasses to return the true
          preference item type: PI_group, PI_list, PI_radio, PI_text,
          PI_toggle, PI_option, PI_custom, PI_empty, PI_label, or
          PI_separator.  These correspond to the subclasses VkPrefGroup,
          VkPrefList, VkPrefRadio, VkPrefText, VkPrefToggle, VkPrefOption,
          VkPrefCustom, VkPrefEmpty, VkPrefLabel, and VkPrefSeparator,
          respectively.

   activate()
           void activate();
           void deactivate();


          Activate and deactivate will sensitize and desensitize,
          respectively, the preference object.  The default state is
          sensitive.

   changed()
           virtual Boolean changed(void);


          This method indicates whether the current value differs from the
          real value.  Applications may want to call this method for
          preference objects when to test whether the user has actually
          changed the value.  Typically, a VkPrefDialog is used and
          applications use this method in the apply callback.

   isContainer()
           virtual Boolean isContainer(void);


          Indicates whether this object contains other preference objects
          (e.g. VkPrefList, VkPrefGroup).

   labelHeight()
           virtual Dimension labelHeight(void);
           virtual void setLabelHeight(Dimension height);


          The labelHeight method returns the height, in pixels, of the label
          widget.  The setLabelHeight method changes the height.

   baseHeight()
           virtual Dimension baseHeight(void);
           virtual void setBaseHeight(Dimension height);


          The baseHeight method returns the height, in pixels, of the base
          widget.  The setBaseHeight method changes the height.

   labelWidget()
           Widget labelWidget(void);


          Returns the label widget for the preference object.  If there is no
          label widget, NULL is returned.

INHERITED MEMBER FUNCTIONS
   Inherited from VkComponent
          installDestroyHandler(), removeDestroyHandler(), widgetDestroyed(),
          setDefaultResources(), getResources(), manage(), unmanage(),
          baseWidget(), okToQuit(), _name, _baseWidget, _w, deleteCallback


   Inherited from VkCallbackObject
          callCallbacks(), addCallback(), removeCallback(),
          removeAllCallbacks(),

KNOWN DERIVED CLASSES
     VkPrefGroup, VkPrefList, VkPrefRadio, VkPrefText, VkPrefToggle,
     VkPrefOption, VkPrefCustom, VkPrefEmpty, VkPrefLabel, VkPrefSeparator,

KNOWN CLASSES THAT USE THIS CLASS
     VkPrefDialog, VkPrefGroup, VkPrefList, VkPrefRadio,

SEE ALSO
     VkComponent, VkPrefDialog, VkPrefGroup, VkPrefList, VkPrefRadio
     ViewKit Programmer's Guide
     The X Window System, DEC Press, Bob Sheifler and Jim Gettys
     The X Window System Toolkit, DEC Press, Paul Asente and Ralph Swick
     The OSF/Motif Programmers Reference, Prentice Hall, OSF