How do I use the rectangle function in a GUI axes using AppDesigner?

I am trying to include this function in my GUI on AppDesigner, but it keeps drawing an error message.

function GUIshipPlacement() 

for i = 0:3
            for j = 0:3
                rectangle(app.UIAxes,'Position', [i, j, 1, 1], 'FaceColor', [0 0.4470 0.7410], ...
                'EdgeColor', 'k');
                rectangle(app.UIAxes,'Position', [i+0.375, j+0.375, 0.25, 0.25], ...
                'Curvature', [1, 1], 'FaceColor', [1, 1, 1], 'EdgeColor', [0, 0, 1]);
            end
end

Error Msg:

Unable to resolve the name app.UIAxes.

Error in GUIshipPlacement (line 13) rectangle(app.UIAxes,'Position', [i, j, 1, 1], 'FaceColor', [0 0.4470 0.7410], ...

Answer 1

[Adam Danz]

To specify the parent handle, use the parent name-value pair, but the syntax you used should have also worked.

rectangle('Position', [i, j, 1, 1], 'FaceColor', [0 0.4470 0.7410], ...
                'EdgeColor', 'k','Parent',app.UIAxes)

or

rectangle(app.UIAxes,'Position', [i, j, 1, 1], 'FaceColor', [0 0.4470 0.7410], ...
                'EdgeColor', 'k')              'EdgeColor', 'k')

This leads me to believe that you're using a non-existant handle to your UIAxes.

[Francis Silvestri]

Thankyou for the response.

The GUI is still showing this error after the code is run:

Unable to resolve the name app.UIAxes.

Error in GUIshipPlacement (line 14)

'EdgeColor', 'k','Parent',app.UIAxes);

[Adam Danz]

I just modified my answer because I realized the syntax you used should have also worked. The problem is probably that you're using a handle that doesn't exist.

Is this "app.UIAxes" your actual axes handle?