Matlab GUI Tutorial - Close GUI Confirmation

Introduction

This tutorial will show you how to create a confirmation window when you attempt to close the GUI. Sometimes, the user might accidentally close the GUI window without meaning to. To protect against this, we can implement a confirmation window that appears when the user attempts to close the GUI. This feature can protect the user from losing any work that has been performed.

This tutorial is written for those with some experience creating a Matlab GUI. If you’re new to creating GUIs in Matlab, you should visit this tutorial first. Basic knowledge of Matlab is highly recommended. Matlab version 2007a is used in writing this tutorial. Both earlier versions and new versions should be compatible as well (as long as it isan’t too outdated). Let’s get started!

Creating the Confirmation Window: Method 1

First, you need to add the following line of code to the opening function of your GUI.
```
set(handles.figure1,'CloseRequestFcn',@closeGUI);
```
This line is of code is telling matlab to run the closeGUI function once someone attempts to close the GUI figure. Make sure to put this line of code before the line
```
guidata(hObject, handles);
```

Next, copy this code at the end of the GUI .m file OR in a separate .m file, but make sure it’s saved in the same directory where the GUI files are located.

function closeGUI(src,evnt)
%src is the handle of the object generating the callback (the source of the event)
%evnt is the The event data structure (can be empty for some callbacks)
selection = questdlg('Do you want to close the GUI?',...
                     'Close Request Function',...
                     'Yes','No','Yes');
switch selection,
   case 'Yes',
    delete(gcf)
   case 'No'
     return
end

Creating the Confirmation Window: Method 2

First, you need to add the following line of code to the opening function of your GUI.
```
set(handles.figure1,'CloseRequestFcn','closeGUI');
```
Notice that instead of the @, we use the single quotation marks. By using the single quotation marks, you are assigning a separate m-file to the close request function of the figure. Make sure to put this line of code before the line
```
guidata(hObject, handles);
```

Next, copy this code into a separate .m file, but make sure it’s saved in the same directory where the GUI files are located. Notice that we did not define any input arguments here.

function closeGUI
 
selection = questdlg('Do you want to close the GUI?',...
                     'Close Request Function',...
                     'Yes','No','Yes');
switch selection,
   case 'Yes',
    delete(gcf)
   case 'No'
     return
end

And that’s it!!! Pretty simple like I mentioned. If you want to see an example, go ahead to the next page.

Pages: 1 2

4 Responses to “Matlab GUI Tutorial - Close GUI Confirmation”

on 04 Jan 2008 at 10:06 am 1Oskar Vivero

Hello!

I have found some really interesting tricks and guidelines for GUI programming in Matlab. I was testing this particular code, and Matlab will output an error:

??? Undefined function or variable ‘closeGUI’.

??? Error while evaluating figure CloseRequestFcn

I corrected it by changing the opening function line to

set(handles.figure1,’CloseRequestFcn’,@closeGUI);

and also, by changing the closeGUI function line to accept 2 arguments (src,evnt) as per matlab’s help

function my_closereq(src,evnt)
% User-defined close request function
% to display a question dialog box
selection = questdlg(’Close This Figure?’,…
‘Close Request Function’,…
‘Yes’,'No’,'Yes’);
switch selection,
case ‘Yes’,
delete(gcf)
case ‘No’
return
end

on 04 Jan 2008 at 10:56 am 2Quan Quach

thanks oscar for pointing that out. there are two ways to go about doing this.

you can define the closeGUI function from within the GUI .m file, or you can define the closeGUI function inside a separate m-file. i will update the tutorial to show how to do it both ways.

on 19 Feb 2008 at 1:47 pm 3serotonin

Heya,
could you wright a small piece of
% your details
if we would like to give you credits in our code for your functions

Thanks for the help

on 15 Oct 2008 at 2:32 pm 4Anonymous

Hey Quan, all of your tutorials are very helpful. I have a quick question though, how do you pass the handles structure into the the closeGUI function? I wanted to clean up some serial port objects before my GUI closes, but I can’t seem to get it to recognize the handles structure.

This is an idea of what I want to do:
function closeGUI(src,evnt,handles)
fclose(handles.port);
delete(handles.port);
clear handles.port;

Thanks in advance.

blinkdagger