Simple Problem - Message Box Function

I have no experience with GUI programing in Matlab. I've written a very simple callback function to display some text when a message box is closed. The text never shows, so I think the callback function is not being called. Can you please take a look and tell me what I'm doing wrong?

Cheers, Josh

function messageBox

    h1=msgbox('Message Display','','none','non-modal');
        set(h1,'CloseRequestFcn',@closeMsg);

    function closeMsg(src,eventdata)
       disp('working')
    end

    waitfor(h1)

end

Answer 1

[Matt Fig]

function messageBox

      h1=msgbox('Message Display','','none','non-modal');
      set(h1,'Deletefcn',@closeMsg);

      function closeMsg(src,eventdata)
         disp('working')
      end

end

If you look at the code for MSGBOX, you will see that pressing the button calls DELETE, which does not use the closerequestfcn. You can see this in the doc for CLOSE (but not in the doc for DELETE?).

[Matt Tearle]

To elaborate: the action is actually a callback for the pushbutton, which is a child of the message box window. Try this to see what's going on:

h1=msgbox('Message Display','','none','non-modal');

h = findobj(h1,'type','uicontrol');

get(h,'Callback')

So you can either change that callback (set(h,'Callback',@closeMsg)) or, as Matt Fig says, change the Deletefcn callback for the window, which is invoked by the Callback callback of the uicontrol (yes, that sentence does make sense...!).

Not sure if that clarified anything at all!

[Matt Tearle]

BTW, notice that if you click the "x" close button on the window (top right corner), your code actually works. *That* is calling the CloseRequestFcn callback.

[Matt Fig]

*That* is calling the CloseRequestFcn callback.

Not quite like the OP is imagining, I would guess.

(Try it out...)

Answer 2

[Sean de Wolski]

You're modifying the closerequestfcn not the callback function for when it's pushed. If you click on the x like you're trying to exit the message box and then click on the okay button it will display 'working'.

[Matt Fig]

But that is not the problem, see the end of my post for explanation...

[Sean de Wolski]

But not if you click the X in the corner! If you click the X in the corner it does call the closerequestfcn and once the waitfor() is taken care of by deleting (by clicking the okay button) it will execute the closerequestfcn.

[Matt Fig]

True enough, see my comment above on my answer. BTW, I was commenting (on your answer) on your previously posted code, not on your newer explanation, which is perfectly fine.

Answer 3

[Josh]

I now understand.

Thank you all for your thorough answers.