Specifications

4 Programming GUIs
4-34
Callbacks for Specific Components
Some components have additional properties that execute callback routines
with the appropriate user action:
•
Callback — MATLAB executes the specified callback when a user activates
a user interface control (
uicontrol) or menu (uimenu) object, for example,
when a user presses a push button or selects a menu item.
•
KeyPressFcn — MATLAB executes the specified callback when a user
presses a key and the callback’s component has focus.
•
ResizeFcn — MATLAB executes the specified callback routine when users
resize a panel (
uipanel) or button group (uibuttongroup) object.
•
SelectionChangeFcn — MATLAB executes the specified callback routine
when a user selects a different radio button or toggle button in a button
group component.
Which Callback Executes
Clicking on an enabled uicontrol prevents any ButtonDownFcn and
WindowButtonDownFcn callbacks from executing. If you click on an inactive
uicontrol, figure, or other graphics objects having callbacks defined, MATLAB
first executes the
WindownButtonDownFcn of the figure (if defined) and then the
ButtonDownFcn of the object targeted by the mouse click.
Adding a Callback
To add a callback subfunction to the GUI M-file, click the right mouse button
while the object is selected to display the Layout Editor context menu. Select
the desired callback from the context menu and GUIDE adds the subfunction
stub to the GUI M-file.