MATLAB Function Reference

Uicontextmenu Properties

You can set and query graphics object properties in two ways:

• The Property Inspector is an interactive tool that enables you to see and change object property values. The Property inspector is available from GUIDE, or use the inspect function at the command line.
• The set and get functions enable you to set and query the values of properties.

For more information about changing the default value of a property see Setting Default Property Values. For an example, see the CreateFcn property.

UicontextmenuProperties

This section lists all properties useful to uicontextmenu objects along with valid values and descriptions of their use. Curly braces {} enclose default values.

Property	Purpose
BusyAction	Callback routine interruption
Callback	Control action
Children	The uimenus defined for the uicontextmenu
CreateFcn	Callback routine executed during object creation
DeleteFcn	Callback routine executed during object deletion
HandleVisibility	Whether handle is accessible from command line and GUIs
Interruptible	Callback routine interruption mode
Parent	Uicontextmenu object's parent
Position	Location of uicontextmenu when Visible is set to on
Tag	User-specified object identifier
Type	Class of graphics object
UserData	User-specified data
Visible	Uicontextmenu visibility

Callback routine interruption. If a callback is executing and the user triggers an event (such as a mouse click) on an object for which a callback is defined, the callback associated with the new event uses the value of BusyAction to decide whether or not to attempt to interrupt the executing callback.

• If the value is cancel, the event is discarded and the second callback does not execute.
• If the value is queue, and the Interruptible property of the first callback is on, the second callback is added to the event queue and executes in its turn after the first callback finishes execution.

Note    If the interrupting callback is a DeleteFcn or CreateFcn callback or a figure's CloseRequest or ResizeFcn callback, it interrupts an executing callback regardless of the value of that object's Interruptible property. See the Interruptible property for information about controlling a callback's interruptibility.

This property has no effect on uicontextmenu objects.

Control action. A routine that executes whenever you right-click an object for which a context menu is defined. The routine executes immediately before the context menu is posted. Define this routine as a string that is a valid MATLAB expression or the name of an M-file. The expression executes in the MATLAB workspace.

The uimenus defined for the uicontextmenu.

This property has no effect on uicontextmenu objects.

Callback routine executed during object creation. The specified function executes when MATLAB creates a uicontextmenu object. MATLAB sets all property values for the uicontextmenu before executing the CreateFcn callback so these values are available to the callback. Within the function, use gcbo to get the handle of the uicontextmenu being created.

Setting this property on an existing uicontextmenu object has no effect.

You can define a default CreateFcn callback for all new uicontextmenus. This default applies unless you override it by specifying a different CreateFcn callback when you call uicontextmenu. For example, the code

• set(0,'DefaultUicontextmenuCreateFcn','set(gcbo,...
      ''Visible'',''on'')')
  

creates a default CreateFcn callback that runs whenever you create a new context menu. It sets the default Visible property of a context menu.

To override this default and create a context menu whose Visible property is set to a different value, call uicontextmenu with code similar to

• hpt = uicontextmenu(...,'CreateFcn','set(gcbo,...
  ''Visible'',''off'')')
  

Note    To override a default CreateFcn callback you must provide a new callback and not just provide different values for the specified properties. This is because the CreateFcn callback runs after the property values are set, and can override property values you have set explicitly in the uicontextmenu call. In the example above, if instead of redefining the CreateFcn property for this uicontextmenu, you had explicitly set Visible to off, the default CreateFcn callback would have set Visible back to the default, i.e., on.

See Function Handle Callbacks for information on how to use function handles to define a callback function.

Delete uicontextmenu callback routine. A callback routine that executes when you delete the uicontextmenu object (e.g., when you issue a delete command or clear the figure containing the uicontextmenu). MATLAB executes the routine before destroying the object's properties so these values are available to the callback routine.

The handle of the object whose DeleteFcn is being executed is accessible only through the root CallbackObject property, which you can query using gcbo.

See Function Handle Callbacks for information on how to use function handles to define a callback function.

Control access to object's handle. This property determines when an object's handle is visible in its parent's list of children. When a handle is not visible in its parent's list of children, it is not returned by functions that obtain handles by searching the object hierarchy or querying handle properties. This includes get, findobj, gca, gcf, gco, newplot, cla, clf, and close. Neither is the handle visible in the parent figure's CurrentObject property. Handles that are hidden are still valid. If you know an object's handle, you can set and get its properties, and pass it to any function that operates on handles.

• Handles are always visible when HandleVisibility is on.
• Setting HandleVisibility to callback causes handles to be visible from within callback routines or functions invoked by callback routines, but not from within functions invoked from the command line. This provides a means to protect GUIs from command-line users, while allowing callback routines to have complete access to object handles.
• Setting HandleVisibility to off makes handles invisible at all times. This may be necessary when a callback routine invokes a function that might potentially damage the GUI (such as evaluating a user-typed string), and so temporarily hides its own handles during the execution of that function.

You can set the root ShowHiddenHandles property to on to make all handles visible, regardless of their HandleVisibility settings. This does not affect the values of the HandleVisibility properties.

This property has no effect on uicontextmenu objects.

Callback routine interruption mode. If a callback is executing and the user triggers an event (such as a mouse click) on an object for which a callback is defined, that callback attempts to interrupt the first callback. MATLAB processes the callbacks according to these factors:

• The Interruptible property of the object whose callback is executing
• Whether the executing callback contains drawnow, figure, getframe, pause, or waitfor statements
• The BusyAction property of the object whose callback is waiting to execute

If the Interruptible property of the object whose callback is executing is on (the default), the callback can be interrupted. Whenever the callback calls one of the drawnow, figure, getframe, pause, or waitfor functions, the function processes any events in the event queue, including the waiting callback, before performing its defined task.

If the Interruptible property of the object whose callback is executing is off, the callback cannot be interrupted (except by certain callbacks; see the note below). The BusyAction property of the object whose callback is waiting to execute determines what happens to the callback.

Note    If the interrupting callback is a DeleteFcn or CreateFcn callback or a figure's CloseRequest or ResizeFcn callback, it interrupts an executing callback regardless of the value of that object's Interruptible property. The interrupting callback starts execution at the next drawnow, figure, getframe, pause, or waitfor statement. A figure's WindowButtonDownFcn callback routine, or an object's ButtonDownFcn or Callback routine are processed according to the rules described above.

Uicontextmenu's parent. The handle of the uicontextmenu's parent object. You can move a uicontextmenu object to another figure, uipanel, or uibuttongroup by setting this property to the handle of the new parent.

Uicontextmenu's position. A two-element vector that defines the location of a context menu posted by setting the Visible property value to on. Specify Position as

• [x y]
  

where vector elements represent the horizontal and vertical distances in pixels from the bottom left corner of the figure window, panel, or button group to the top left corner of the context menu.

This property has no effect on uicontextmenu objects.

This property has no effect on uicontextmenu objects.

User-specified object label. The Tag property provides a means to identify graphics objects with a user-specified label. This is particularly useful when constructing interactive graphics programs that would otherwise need to define object handles as global variables or pass them as arguments between callback routines. You can define Tag as any string.

Class of graphics object. For uicontextmenu objects, Type is always the string 'uicontextmenu'.

This property has no effect on uicontextmenus.

User-specified data. Any data you want to associate with the uicontextmenu object. MATLAB does not use this data, but you can access it using set and get.

Uicontextmenu visibility. The Visible property can be used in two ways:

• Its value indicates whether the context menu is currently posted. While the context menu is posted, the property value is on; when the context menu is not posted, its value is off.
• Its value can be set to on to force the posting of the context menu. Similarly, setting the value to off forces the context menu to be removed. When used in this way, the Position property determines the location of the posted context menu.

uicontextmenu

uicontrol

© 1994-2005 The MathWorks, Inc.