MATLAB: Appdesigner Edit Field (Numeric) won’t update values.

appdesigneredit fieldMATLAB

Hi. I have 2 Edit Fields in my app – "Delay" and "Step". The goal is to set the step size and update the delay value. It is in principle working, but only if I change the two values every time. If I want to keep the step size at 20, I would expect that the Delay value would increase by 20 every time I hit the enter button. Moreover, this was working with the Guide, but when I transferred to Appdesigner recently (by using the migration functionality), I noticed that the Delay value would update only when I change the step size (or the Delay value itself). Here is my code. You can see the old Guide-style code lines commented, as well.
% Value changed function: pumpdelay
        function pumpdelay_Callback(app, event)
            % Create GUIDE-style callback args - Added by Migration Tool

            [hObject, eventdata, handles] = convertToGUIDECallbackArguments(app, event); %#ok<ASGLU>

            
            % hObject    handle to pumpdelay (see GCBO)
            % eventdata  reserved - to be defined in a future version of MATLAB

            % handles    structure with handles and user data (see GUIDATA)

            
            % Hints: get(hObject,'String') returns contents of pumpdelay as text
            %        str2double(get(hObject,'String')) returns contents of pumpdelay as a double
            
            pumpdelay = str2num(app.pumpdelay.Value)
            delaystep = str2num(app.delaystep.Value)
            pumpdelay = pumpdelay + delaystep
            app.pumpdelay.Value = num2str(pumpdelay); % Set

            
%             pumpdelay = str2num(get(handles.pumpdelay, 'String'));

%             delaystep = str2num(get(handles.delaystep, 'String'));

%             pumpdelay = pumpdelay + delaystep;

%             set(handles.pumpdelay, 'String', num2str(pumpdelay));

%             guidata(hObject, handles);

%             CARS_GUI_2pulse_18('calculate_Callback',handles.calculate,[],handles);
        end
        
        % Value changed function: delaystep
        function delaystep_Callback(app, event)
            % Create GUIDE-style callback args - Added by Migration Tool
            [hObject, eventdata, handles] = convertToGUIDECallbackArguments(app, event); %#ok<ASGLU>
            
            % hObject    handle to delaystep (see GCBO)
            % eventdata  reserved - to be defined in a future version of MATLAB
            % handles    structure with handles and user data (see GUIDATA)
            
            % Hints: get(hObject,'String') returns contents of delaystep as text
            %        str2double(get(hObject,'String')) returns contents of delaystep as a double
            
            pumpdelay = str2double(app.pumpdelay.Value)
            delaystep = str2double(app.delaystep.Value)
            pumpdelay = pumpdelay + delaystep
            app.pumpdelay.Value = num2str(pumpdelay); % Set
            
%             pumpdelay = str2num(get(handles.pumpdelay, 'String'));
%             delaystep = str2num(get(handles.delaystep, 'String'));
%             pumpdelay = pumpdelay + delaystep;
%             set(handles.pumpdelay, 'String', num2str(pumpdelay));
%             guidata(hObject, handles);
        end

Best Answer

Hello,
Based on the comment section, callback should be written this way
function Push_Button_Callback(app, event)
    app.pumpdelay.Value = app.pumpdelay.Value + app.delaystep.Value
    CalculateSmth(app)
end
If you create a helper function in your app, just call it, there's no need for another callback in App Designer. Just a reminder that you can not use variables that are defined in another callbacks. Reference the values from app components, or create a property to get around it. 
function CalculateSmth(app)
    % code
end
Helper Functions
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