Defining Context Menus :: Laying Out GUIs and Setting Properties (Creating Graphical User Interfaces)

Creating Graphical User Interfaces

Defining Context Menus

A context menu is displayed when a user right-clicks on the object for which the menu is defined. The Menu Editor enables you to define context menus and associate them with objects in the layout.

See Defining Menus for the Menu Bar for information about defining menus in general.

Creating the Parent Menu

All items in a context menu are children of a menu that is not displayed on the figure menu bar. To define the parent menu, select New Context Menu from the Menu Editor's toolbar.

menu editor with cursor pointing to new context menu

Note You must select the Menu Editor's Context Menus tab before you begin to define a context menu.

Select the menu and specify the Tag to identify the context menu (axes_context_menu in this example).

Adding Items to the Context Menu

Create the items that will appear in the context menu using New Menu Item on the Menu Editor's toolbar.

menu editor with cursor pointing to new menu item

When you select the menu item, the Menu Editor displays fields for you to enter the Label and Tag properties of the menu item.

adding blue and red background color to the axes context menu

You can also

Select the Separator above this item check box to display a separator above the menu item when the menu is first opened.
Select the Check mark this item check box to display a check next to the menu item when the menu is first opened.

A check is particularly useful to indicate the current state of the menu item. For example, suppose you have a menu item called Show axes that toggles the visibility of an axes between visible and invisible each time the user selects the menu item. If you want a check to appear next to the menu item when the axes are visible, add the following code to the callback for the Show axes menu item:
- ```
if strcmp(get(gcbo, 'Checked'),'on')
    set(gcbo, 'Checked', 'off');
else 
    set(gcbo, 'Checked', 'on');
end
```
This changes the value of the Checked property of the menu item from on to off or vice versa each time a user selects the menu item.

If you set the axes to be visible when a user first opens the GUI, make sure to select the Check mark this item check box in the Menu Editor, so that a check will appear next to the Show axes menu item initially.

Select the Enable this item check box so that the user can select this item when the menu is first opened. If you deselect this option, the menu item appears dimmed when the menu is first opened, and the user cannot select it.
Click the More options button to open the Property Inspector where you can change all uimenu properties.

Associating the Context Menu with an Object

In the Layout Editor, select the object for which you are defining the context menu. Use the Property Inspector to set this object's UIContextMenu property to the name of the desired context menu.

property inspector menu

In the GUI M-file, complete the callback subfunction for each item in the context menu. Each callback executes when a user selects the associated context menu item. See Menu Callbacks for information on defining the syntax.

Menu Callbacks Setting the Tab Order