Function output does not get recocnized

Hi guys,

in the following the example code of an Matlab App I'm trying to figure out.

When an option gets selected in the pushdown menu, the edit fields should get a defined value (already working). When I push the start Button, the variable e should get calculated with selected values in another function and displayed in an editfield.

The problem is, I get the error message "Unrecognized function or variable 'u'." when I press start. Maybe somebody could help me with this?

    methods (Access = private)
          
    function [u,v,x] = DropdownValueChanged(app, event)
        selectedOption = app.DropDown.Value;
        % Abhängig von der ausgewählten Option die EditField-Werte aktualisieren
        if strcmp(selectedOption, 'Option 1')
            app.EditField.Value = 2;
            app.EditField_2.Value = 3;
            app.EditField_3.Value = 5;
        elseif strcmp(selectedOption, 'Option 2')
            app.EditField.Value = 0;
            app.EditField_2.Value = 0;
            app.EditField_3.Value = 0;  
        end
      u=app.EditField.Value;
      v=app.EditField_2.Value;
      x=app.EditField_3.Value; 

    end

        
    function func3(app,u,v,x)
            e=u+v+x;
            app.EditField2.Value=e;
        end
end

callbacks:

  % Callbacks that handle component events
    methods (Access = private)

        % Value changed function: DropDown
        function DropDownValueChanged(app, event)
            
            value = app.DropDown.Value;
            
        end

        % Value changed function: EditField
        function EditFieldValueChanged(app, event)
            value = app.EditField.Value;
            
        end

        % Value changed function: EditField_2
        function EditField_2ValueChanged(app, event)
            value = app.EditField_2.Value;
            
        end

        % Value changed function: EditField_3
        function EditField_3ValueChanged(app, event)
            value = app.EditField_3.Value;
            
        end

        % Value changed function: EditField2
        function EditField2ValueChanged(app, event)
            value = app.EditField2.Value;
            
        end

        % Value changed function: StartButton
        function StartButtonValueChanged(app, event)
      
      DropdownValueChanged(app, event)
           func3(u,v,x)
        end

        % Clicked callback: DropDown
        function DropDownClicked(app, event)
            item = event.InteractionInformation.Item;
            DropdownValueChanged(app, event)
        end

[Stephen23]

https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html

Answer 1

[Marlon]

I found the way:

function func3(app)

[u,v,x] = DropdownValueChanged(app);

e=u+v+x;

app.EditField2.Value=e;

end

[Image Analyst]

I'm not sure why you have two DropdownValueChanged functions. This one:

function [u,v,x] = DropdownValueChanged(app, event)
        selectedOption = app.DropDown.Value;
        % Abhängig von der ausgewählten Option die EditField-Werte aktualisieren
        if strcmp(selectedOption, 'Option 1')
            app.EditField.Value = 2;
            app.EditField_2.Value = 3;
            app.EditField_3.Value = 5;
        elseif strcmp(selectedOption, 'Option 2')
            app.EditField.Value = 0;
            app.EditField_2.Value = 0;
            app.EditField_3.Value = 0;  
        end
      u=app.EditField.Value;
      v=app.EditField_2.Value;
      x=app.EditField_3.Value; 
    end

and this one

    % Value changed function: DropDown
    function DropDownValueChanged(app, event)
    
    value = app.DropDown.Value;
    
    end

Anyway, I hope my answer let you realize that you needed to get u, v, and x before calling func3(). Your first version of DropdownValueChanged will give you those values if you accept them (as you did now in your answer).

Answer 2

[Image Analyst]

When you click Start, this code runs:

% Value changed function: StartButton
function StartButtonValueChanged(app, event)
    DropdownValueChanged(app, event)
    func3(u,v,x)
end

Variables are not global unless attached to the app structure, or you declare them global. So inside that function, it has no idea what u, v, and x are because you never defined them in that function. If they were defined somewhere else, then you need to get them into that function, like make them fields of the app variable or assign them some values right there in that function.