i just wanted to add my solution to the continuous slider problem, which seems to be the simpliest/easiest way to understand (imho):

1. Create the control:

    myslider = uicontrol(topWindowHandle, ...
        'Style', 'slider', ...
        'Min', 0, 'Max', 100, ...
        'Value', 25, ...
        'SliderStep', [0.05 0.2], ...
        'Position', [60 100 350 18]);

2. Add a listener to the Value-property:

addlistener(handle(myslider), 'Value', 'PostSet', @slider_callback);

3. Implement the slider-callback-function:

    function slider_callback(hObject, eventdata)
        obj = get(eventdata, 'AffectedObject');
        val = get(obj, 'Value');
        display(val);
    end

Now, val contains the actual slider value, because the AffectedObject-property holds the desired slider control, from which we can obtain our slider-value.

Greetings

John

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!

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

>> 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.

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

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