MATLAB: How to pass parameters computed in different functions separately into another function

functionuicontrol

Hello,
I have three uicontrol popupmenus and I am supposed to select one item from all popupmenus. Each time I select an item, the appropriate Callback function computes a value (same parameter). After selecting the three items from all three different popupmenus, I press a pushbutton to compute another value (some parameter) which is computed by using the parameters from the previously selected items. here is how it looks like:
 Selection1 = uicontrol('Style','popupmenu',...
                           'String',{'Selection1 ';'Selection2 ';'Selection3'},...
                           'Callback',@Selection1_Callback);
Selection2 = uicontrol('Style','popupmenu',...
                         'String',{'Selection4 ';'Selection5 ';'Selection6'},...
                         'Callback',@Selection2_Callback);
Selection3 = uicontrol('Style','popupmenu',...
                         'String',{'Selection7';'Selection8';'Selection9'},...
                         'Callback',@Selection3_Callback);
 pushbutton = uicontrol('Style', 'pushbutton',...
                       'String', 'Compute', ...
                       'Callback' @pushbutton_Callback);
 edit = uicontrol('Style', 'edit',...
                  'String', '');
 function Selection1_Callback (hObject, eventdata, handles)
 here I compute parameter 1
 end
 function Selection2_Callback (hObject, eventdata, handles)
 here I compute parameter 2
 end
 function Selection3_Callback (hObject, eventdata, handles)
 here I compute parameter 3
 end
 function pushbutton_Callback (hObject, eventdata, handles)
 here I use parameters 1, 2, 3 in order to compute parameter 4
 set(edit, 'String', Parameter4);
 end
So how I can pass parameters 1, 2, and 3 into the pushbutton_Callback function so I could compute parameter 4 and then show it in edit box?
Thank you,
Aleksandar

Best Answer

I think that nested functions are the simplest and most intuitive way of passing data between GUI callback functions:
function mainGUI()
...
p1 = [];
p2 = [];
p3 = [];
%




    function Selection1_Callback (hObject, eventdata)
    p1 = ...compute parameter 1
    end
%
    function Selection2_Callback (hObject, eventdata)
    p2 = ...compute parameter 2
    end
%
    function Selection3_Callback (hObject, eventdata)
    p3 = ...compute parameter 3
    end
%
    function pushbutton_Callback (hObject, eventdata)
    p4 = p1 + p2 + p3;
    set(edit, 'String', num2str(p4))
    end
%
end % end of mainGUI function
For other ways of passing data between callback functions you can read the MATLAB documentation:
https://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html
Note: avoid global and assignin: these will not help you to write good code.
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