App Designer - confirm exit when application is closed from Windows bar

Hi guys,

I have a simple question regarding App Designer.

Sometimes I accidentally click the close button which exits the application (obviously). Is there a way to implement the confirmation dialog?

Answer 1

[Adam Danz]

Add a close request function to your app that requires confirmation.

1. From AppDesigner > Design View, right click the figure background, go down to "Callbacks", and select "Add CloseRequestFcn function callback".

2. A UIFigureCloseRequest() function will be added in Code View. Add this to the function where app.UIFigure is the handle to your app figure.

YN = uiconfirm(app.UIFigure,'Do you want to close the app?', 'Close request');
if strcmpi(YN,'OK')
    delete(app)
end

[Mario Malic]

Works great, I have not seen this "almost hidden" menu before.

Thank you Adam!

[Adam Danz]

You can also access the figure's callback functions by clicking on the figure handle in the Component Browser and then click "callbacks" in the lower half of the panel on the right.

[Mario Malic]

I didn't use callbacks for the figure before,and I didn't even know that they exist. Thanks for the hint.

[Adam Danz]

Glad I could help!

[Chirag]

@Adam Danz Thanks a lot for this Answer. It helped me too.

[Adam Danz]

Thanks for the feedback @Chirag!

[Arash Razi]

Nice,good job.

[dpb]

That's a help, indeed, but is there a way to disable the window 'Close' "X" (and Alt-F4) programmatically to prevent the user from doing so while the app is busy doing something that could result in files left open, etc., ...? Can (and do) disable the programmed "Quit" button when beginning processing and then reenable it when done, but would be agoodthing™ to be able to short-circuit an accidental attempt otherwise, because they could still respond 'Yes' to the prompt...although I guess one could test a status flag in the callback function and refuse is that were set...

[Image Analyst]

@dpb what if you added the close request callback and simply had it return without doing anything

return; % Bail out without closing.

I don't think it would get rid of the little x in the upper right of the title bar though. However, if you set the 'WindowState' property of the figure to 'fullscreen', it should not have a title bar and should cover up the task bar at the bottom.

app.UIFigure.WindowState = 'fullscreen';

[dpb]

Yeah, @Image Analyst, that's what I've done for the moment with further amplification in the other thread on the callbacks in the particular app being confounded by my prior actions, not knowing better at the time...

[Adam Danz]

This was such a great question that I wrote an article about it this morning.

https://www.mathworks.com/matlabcentral/discussions/tips/881185