GUI Button Does Not Change Colour

Hi there,

I created a simple GUI using appdesginer.

As soon as I press the start button, it should change to stop, execute the code block and then change back to start. My function looks like this:

function StartButtonPushed(app, event)

tic

app.StartButton.BackgroundColor = [0.95 0.28 0.28]; % red

app.StartButton.Text = 'STOP';

% bunch of code

app.StartButton.BackgroundColor = [0.96 0.96 0.96]; % default grey

app.StartButton.Text = 'Start';

toc

end

tic/toc returns:

>> Elapsed time is 5.617925 seconds.

My button doesn't change the colour or text when Start is pressed. If I put a breakpoint in my code block, I do see the text and colour change to stop and red respectively.

Is 5s not enough gap for the button to change or am I doing somthing wrong?

Thanks for the help!

Answer 1

[Voss]

Insert drawnow commands immediately after changing the Color/Text, in order to see the changes right away:

function StartButtonPushed(app, event)
tic
app.StartButton.BackgroundColor = [0.95 0.28 0.28]; % red
app.StartButton.Text = 'STOP';

drawnow();

% bunch of code
app.StartButton.BackgroundColor = [0.96 0.96 0.96]; % default grey
app.StartButton.Text = 'Start';

drawnow();

toc
end

Reference: https://www.mathworks.com/help/matlab/ref/drawnow.html