How to modified "edit fied (text)" from app design

I need that the ''edit field text'', in my app, is limited to a maximum of 20 characters and a pop-up error message that appears if you enter more than 20 characters.

How could i do?

Answer 1

[Mario Malic]

Add this to the value changed callback, adjust the name of your field.

if length(app.EditField.Value) <= 20
    Text = app.EditField.Value; % If you will use the text
else
%     app.EditField.Value = ''; % you can clear out the text if needed
    f = uifigure;
    Error_Msg = "Error message"
    Error_Title = "Error title";
    uialert(f, Error_Msg, Error_Title,'CloseFcn',@(h,e) close(f));
end

It takes a little bit of time to display the message, if that is an issue, then you can use tooltip, I have no example with tooltip.

Above portion of code creates a new figure which takes a bit of time. Here's a better solution with help from Adam.

if length(app.EditField.Value) <= 20
    Text = app.EditField.Value; % If you will use the text
else
%     app.EditField.Value = ''; % you can clear out the text if needed
    f = app.UIFigure; % f is handle to your app UI figure  
    Error_Msg = "Error message"
    Error_Title = "Error title";
    uialert(f, Error_Msg, Error_Title);
end

[Palma Errico]

It was really useful! Thank you.

[Palma Errico]

@Mario Malic yes I had already made this change to my app, because I realized that the error message was slow. Your help on setting up the code was crucial though. Thanks again!