Comments on: Continuous slider callback

By: claus

claus — Thu, 26 Jan 2012 16:34:47 +0000

Hi, thank you for your help!

I turned my sliders into continuous just by adding two simple mods:

first, add the following 2 lines to your xxxxxx_OpeningFcn:

hListener=addlistener(handles.sliderN, 'ContinuousValueChange', @sliderN_Callback);
setappdata(handles.sliderN,'myListener',hListener);

then, add the following 3 lines to your sliderN_Callback:

if ~(exist('handles','var'))
     handles=guidata(hObject);
end

It works like a charm!

Thank you!

By: Elise

Elise — Sat, 28 May 2011 00:14:39 +0000

Thanks! Handle.listener worked great!

By: Matlab continuous slider callback « Desperate Engineers Blog

Matlab continuous slider callback « Desperate Engineers Blog — Wed, 04 May 2011 08:53:55 +0000

[...] ([uicontrol('Style','slider', ...]) in a MATLAB GUI. Thanks to the posting of Yair Altman on this topic (on his awesome Undocumented Matlab Blog which you shoudl definitely check out), I had no problem [...]

By: Jonas

Jonas — Thu, 21 Apr 2011 14:09:01 +0000

A short update form my side – as I now run on R2011a.

I used to run a listener as proposed (R2010a/b) in the post the following way:

lh = addlistener(sliderhandle, 'ActionEvent',@MyCallback);

The new Version of Matlab (R2011a) gives me a warning that I should not use this method anymore but rather use: a “ContinuousValueChange” Event.
So I end up with:

lh = addlistener(sliderhandle, 'ContinuousValueChange',@MyCallback);

which works pretty smooth. However, besides of that one-time-console-warning I have not found any documented information about this “ContinuousValueChange”-event or other hidden events…

Best, Jonas

By: Yair Altman

Yair Altman — Thu, 07 Apr 2011 10:36:05 +0000

@Jonas – these are essentially the same, except that addlistener adds the listener in a hidden property called Listeners__, rather than in the similarly-hidden ApplicationData property (which is what setappdata does).

>> get(handles.mySlider, 'Listeners__')
ans =
	handle.listener

The actual place where the listener is stored does not matter. It is only important to store listeners together with the listened object, so that they both have exactly the same life-span. Both of these methods do that, by storing the listener in one of the object handle’s properties.

The source code for addlistener is not available in the latest Matlab releases (it’s implemented as an internal function), but it is available and inspectable in Matlab releases up to 2008 (e.g., C:\Program Files\Matlab\R2008a\toolbox\matlab\uitools\private\addlistener.m). This source code is not long (only ~30 code lines) and it’s interesting, so I recommend looking at it.

By: Jonas

Jonas — Thu, 07 Apr 2011 09:56:38 +0000

Dear Yair
Your blog is just wonderful and helps me a lot these days in getting somewhere with my thesis. Thank your for your good work!

Regarding the continuous slider callback, I wonder what the difference between

hListener = handle.listener(handles.mySlider,'ActionEvent',@mySliderMoved);
setappdata(handles.mySlider,'mySliderListener',hListener);

and

hListener = addlistener(handles.mySlider, 'ActionEvent', @mySliderMoved);

exactly is…?

Best,
Jonas

PS. looking forward to your relevations of 2011a – coming tomorrow

By: Florin

Florin — Tue, 08 Mar 2011 23:17:31 +0000

Yair,

Thank you for your quick reply. That worked.
Hope you can maintain this site for a long time.
I wish you all the best.

Regards,
Florin

By: Yair Altman

Yair Altman — Tue, 08 Mar 2011 07:36:29 +0000

@Florin – you probably have the same problem as Cemil and the solution is similar. In your slider callback, instead of using a simple imagesc, directly specify the parent axes:

imagesc('Parent',handles.axes1, 'XData',xdata, 'YData',ydata, ...);

By: Florin

Florin — Tue, 08 Mar 2011 00:59:53 +0000

Hi,

I have been reading this post, but I still have a problem. I am reading and a .tif file and display slices of it with imagesc. I am trying to continuously update this images when moving the slider. I have the same problem as Cemil : a new windows appears and the imagescs are updated in that new figure. As soon as I release the mouse button the intended figure inside my GUI is also updated. I checked the HandleVisibility parameter. I also tried to set the handle with

figure(get(handles.axes1,'Parent'));

Any suggestions for me, pls ?

Thank you.
Florin

By: Cemil Kirbas

Cemil Kirbas — Wed, 02 Jun 2010 13:59:23 +0000

Thank you very much Yair. That was a great help. I changed HandleVisibility of the figure from its default value ‘callback’ to ‘on’ and the problem is solved. I appreciate your help.

Best regards,

Cemil.