App Designer - how to run code before components are created?

I would like to run MATLAB code before the components of the app are initialized. The default workflow is

          function app = time_evolution_app_R2_0_v18_resized

            % Create and configure components
            createComponents(app)

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

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            if nargout == 0
                clear app
            end
        end

Therefore, the first editable code is placed after createComponents() and registerApp() are called. Is there any way to place code before runStartupFcn()?

Specifically, I have a bunch of graphics I use for buttons in the app, which I would like to store in a subfolder. However, the only possibility seems to either (1) place the graphics in the same folder as the app, (2) manually add the subfolder with graphics to my MATLAB path. Is there any way to automatically add a subfolder to the path when running the app, before the app components are created?

[Greg]

This is a rather annoying feature of the App Designer. Would be nice to have some feedback from MathWorks on this.

[Bas Peters]

If you save your .mlapp as a .m in appdesigner, you can edit the script itself. Then just run the .m script to run your app.

[Francesco Fortunato]

It does not work to me, I keep opening file with all wierd symbols

How could I edit it?

[Ankit]

I think you renamed the file. Have you tried exporting from the app designer?

[Francesco Fortunato]

yes, sorry, you're right

It worked

[Will Reeves]

Can I confirm that since October 2019 this reasonable "feature request" hasn't been included?... Or maybe an "advance mode" option that allows a user to freely edit all areas of code?

[Kevin Holly]

As of R2022a, images do not need to be on the MATLAB path to be used in App Designer.

There is a workaround to call addpath with a dummy propery variable

properties (Access = private)
     dummyvariable = addpath('./icons')
end

Answer 1

[Laura V.]

I'm dealing with the same problem but due to another reason. I would like to implement a Matlab version check before createComponents. Implementing a version check in startupFcn would be too late for features like wordwrap that cause an error with older Matlab versions in createComponents....