MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál stáhnout pdf (Strana 210)

8 Programming the GUI

8-38

When a user selects the to file option under the Edit menu’s Copy option, only

the

to file callback is required to perform the action.

Suppose, however, that only certain objects can be copied to a file. You can use

the

Copy item Callback callback to enable or disable the to file item,

depending on the type of object selected.

Opening a Dialog Box from a Menu Callback

The Callback callback for the to file menu item could contain code such as the

following to display the standard dialog box for saving files.

[file,path] = uiputfile('animinit.m','Save file name');

'Save file name'

is the dialog box title. In the dialog box, the filename field

is set to

animinit.m, and the filter set to M-files (*.m). For more information,

see the

uiputfile reference page.

Updating a Menu Item Check

A check is useful to indicate the current state of some menu items. If you

selected

Check mark this item in the Menu Editor, the item initially appears

checked. Each time the user selects the menu item, the callback for that item

must turn the check

on or off. The following example shows you how to do this

by changing the value of the menu item’s

Checked property.

if strcmp(get(gcbo, 'Checked'),'on')

set(gcbo,'Checked','off');

else

set(gcbo,'Checked','on');

end

The gcbo function returns the handle of the object whose callback is executing,

in this case the menu item. The

strcmp function compares two strings and

returns logical

1 (true) if the two are identical and logical 0 (false) otherwise.

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.

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MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál Strana 210