MATLAB Creating Graphical User Interfaces

12 Manage Application-Defined Data

the slider position. To see how it works, copy and paste this code into an editor and run

it.

function my_slider()

hfig = figure();

data = struct('val',0,'diffMax',1);

slider = uicontrol('Parent', hfig,'Style','slider',...

'Units','normalized',...

'Position',[0.3 0.5 0.4 0.1],...

'Tag','slider1',...

'Callback',@slider_callback);

button = uicontrol('Parent', hfig,'Style','pushbutton',...

'Units','normalized',...

'Position',[0.4 0.3 0.2 0.1],...

'String','Display Difference',...

'Callback',@button_callback);

function slider_callback(hObject,eventdata)

sval = hObject.Value;

diffMax = hObject.Max - sval;

data.val = sval;

data.diffMax = diffMax;

end

function button_callback(hObject,eventdata)

display([data.val data.diffMax]);

end

end

The main function defines a struct array called data. When the user moves the slider,

the slider_callback function updates the val and diffMax fields of the data

structure. When the end user clicks the push button, the button_callback function

displays the values stored in data.

Note:Nested functions are not recommended for GUIDE UIs.

Store Data Using the guidata Function

The guidata function provides a way to share data with the figure window. You can

store or retrieve the your data in any callback through the hObject component. This

means that, unlike working with UserData or application data, you do not have to