Change number of drop downs based on spinner value using matlab app designer?

I want to plot a variable number of lines. The number of lines will be set by the spinner value. I want three drop downs to appear for each line so that I can specify linewidth, color, and linestyle. So if spinner value = 1, 3 drop downs will appear in one row. If spinner value = 2, 6 drop downs will appear in 2 rows (3 columns), etc. Is it dynamically possible to change the number of drop downs to appear in my GUI? If so, any recommendations to make this happen?

Thanks

Answer 1

[Image Analyst]

I suggest you place all the drop downs on the figure in App Designer, and then set the visibility of all but the first to off/0/hidden so they aren't shown. Then as you spin the widget, set the visibility of the appropriate drops downs to on/1/shown so that they appear. I think this is much easier than trying to create and place them on the fly.

[Cris LaPierre]

Agreed. This approach is much simpler.

Answer 2

[Cris LaPierre]

It's possible. See this page. You may find this blog post instightful as well.

The hard part is going to be dynamically coming up with the position of the drop boxes.

[James Nestler]

Thanks for both of your answers. I'll look into Image Analysts' today. I'm new to the app designer features so am not sure how to interpret the error I got yesterday. I made the first row of buttons/fields etc. that I want, and I want to add rows with the spinner. The app I'm designing is called VolumeApp2. The spinner value is set at 1 upon initialization, then I click it to 2.

Yesterday I tried the following:

        % Value changed function: NoofSurveysSpinner
        function NoofSurveysSpinnerValueChanged(app, event)
            value = app.NoofSurveysSpinner.Value;
            for i = 2:value
                % Create EditField_25
                app.(['SurveyLabel' num2str(value)]) = uieditfield(app.Plotter2Tab, 'text');
                app.(['SurveyLabel' num2str(value)]).Position = [243 407-20*value 100 22];
    
                % Create BrowseButton_16
                app.(['SurveyBrowse' num2str(value)]) = uibutton(app.Plotter2Tab, 'push');
                app.(['SurveyBrowse' num2str(value)]).Position = [171 407-20*value 60 22];
                app.(['SurveyBrowse' num2str(value)]).Text = 'Browse';
            end
        end
            
            

and got the following error:

Unrecognized property 'SurveyLabel2' for class 'VolumeApp2'.

Error in VolumeApp2/NoofSurveysSpinnerValueChanged (line 469)

app.(['SurveyLabel' num2str(value)]) = uieditfield(app.Plotter2Tab, 'text');

Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 453)

Error while evaluating Spinner PrivateValueChangedFcn.

Could someone please advise as to what this error means and how to avoid it?

Thanks again

[Cris LaPierre]

I don't believe you can dynamically create app properties (but have not confirmed that). At the least, this page shows you the way you are intended to create app properties.

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

If you follow Image Analysts' suggestion, then you will not have to dynamically create component object handles.