MATLAB Central Newsreader - Focus loss using keypresses in 'listbox' GUI control

Focus loss using keypresses in 'listbox' GUI control

Ian Clarkson — Mon, 12 May 2008 14:16:04 -0400

Hi everybody,

I'm having some issues with R12.1 trying to do a GUI to
display images. I have a list of files in a listbox, and I
want the axis in the GUI to update with the image that's
selected in the listbox. It currently works fine with a
mouse-click, but I want it to update as I move the
highlighted file in the listbox with the arrow keys. The
highlighting works fine UNTIL I try to draw the image. In
the callback function for the listbox, I have:

axes(handles.axesSampleImage);
imshow(data);

If I comment out these two lines, the arrow keys continue to
slide the selected string around. However, once the axes()
command is issued (even by itself) or imshow (again, even by
itself), the up and down keypresses start going through
previous/next MATLAB commands back in the main window.

I've tried returning focus to the listbox by setting its
visibility off and then on again, and setting focus back to
the figure by calling figure(myhandle). Neither works. I'm
not sure what's changing with the axes() and/or imshow()
commands that makes the GUI lose the ability to send
keypresses to the listbox.

Thanks!

Re: Focus loss using keypresses in 'listbox' GUI control

matt dash — Mon, 12 May 2008 15:18:03 -0400

I have a similar setup where you can scroll through
variables in a list and they are plotted, and it works fine.
(With no need to re-set focus). Maybe try using the image
command instead of imshow, and specify the axes as a
property of the image instead of using the axes command.

Re: Focus loss using keypresses in 'listbox' GUI control

Ian Clarkson — Mon, 12 May 2008 16:38:04 -0400

"matt dash" <n.a@mail.com> wrote in message
<g09n3b$ik6$1@fred.mathworks.com>...
> I have a similar setup where you can scroll through
> variables in a list and they are plotted, and it works fine.
> (With no need to re-set focus). Maybe try using the image
> command instead of imshow, and specify the axes as a
> property of the image instead of using the axes command.

Wicked -- that's totally the solution. Create an image
object using the image() function, then set its properties
accordingly. Focus does not change and the keypresses still
work.

Thanks so much!