Matlab R2020A - App Designer Lamp Behaving Opposite to code

Hi,

I have designed a test app using AppDesigner. I am using a simple slide switch and lamp to test the slide switch action. The idea is when the switch is set to "On" position the lamp colour changes to "Green". When its toggled back to "OFF" the lamp changes to "Red".

My confusion is the lamp behaves opposite to my expectation. When toggled to "Off" position the lamp colour is "Green" and when the toggle is "On" the lamp lights up as "Red". The same behaviour is noticed when I replace the "app.Lamp.Color" property with "app.Lamp.Enable" property. The lamp behviour is opposite of what I expect.

The relevant code section is located within "Switch2ValueChanged(app, event)" callback function.

classdef lamptest < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure      matlab.ui.Figure
        Panel         matlab.ui.container.Panel
        Switch2Label  matlab.ui.control.Label
        Switch2       matlab.ui.control.Switch
        Lamp          matlab.ui.control.Lamp
    end

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

        % Value changed function: Switch2
        function Switch2ValueChanged(app, event)
            value = app.Switch2.Value;
            
            if strcmp(value, "Off")
                app.Lamp.Color = [1,0,0];
            else 
                app.Lamp.Color = [0,1,0];
                    
            end
            
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 338 145];
            app.UIFigure.Name = 'MATLAB App';

            % Create Panel
            app.Panel = uipanel(app.UIFigure);
            app.Panel.Title = 'Panel';
            app.Panel.Position = [30 18 293 106];

            % Create Switch2Label
            app.Switch2Label = uilabel(app.Panel);
            app.Switch2Label.HorizontalAlignment = 'center';
            app.Switch2Label.Position = [60 17 48 22];
            app.Switch2Label.Text = 'Switch2';

            % Create Switch2
            app.Switch2 = uiswitch(app.Panel, 'slider');
            app.Switch2.ValueChangedFcn = createCallbackFcn(app, @Switch2ValueChanged, true);
            app.Switch2.Position = [61 54 45 20];

            % Create Lamp
            app.Lamp = uilamp(app.Panel);
            app.Lamp.HandleVisibility = 'callback';
            app.Lamp.Interruptible = 'off';
            app.Lamp.Position = [217 45 20 20];
            app.Lamp.Color = [1 0 0];

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = lamptest

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Can I request help to troubleshoot this behaviour?

Answer 1

[Image Analyst]

Is app.Switch2.Value a string, like 'on' or 'off'? If so, try strcmpi() instead of strcmp().

Or is it a logical or number like 0 or 1?

[Anand Mohan]

Thanks for the response. After a lot of debugging, nothing was fixed. Then restarted the laptop and now its all good. Some issue on the device causing Matlab to behave incorrectly. Thanks for the help. Next time first step would be turn the PC off and then on.