In MATLAB, how can you have a callback execute while a slider is being dragged?

user-interface matlab callback slider matlab-guide
Bill Cheatham picture Bill Cheatham · May 17, 2011 · Viewed 9.7k times · Source

I have created a MATLAB GUI using GUIDE. I have a slider with a callback function. I have noticed that this callback, which is supposed to execute 'on slider movement', in fact only runs once the slider has been moved and the mouse released.

Is there a way to get a script to run as the slider is being dragged, for live updating of a plot? There would I presume need to be something to stop the script being run too many times.

Answer

gnovice picture gnovice · May 17, 2011

Even though the callback of the slider isn't being called as the mouse is moved, the 'Value' property of the slider uicontrol is being updated. Therefore, you could create a listener using addlistener that will execute a given callback when the 'Value' property changes. Here's an example:

hSlider = uicontrol('Style', 'slider', 'Callback', @(s, e) disp('hello'));
hListener = addlistener(hSlider, 'Value', 'PostSet', @(s, e) disp('hi'));

As you move the slider you should see 'hi' being printed to the screen (the listener callback), and when you release the mouse you will see 'hello' printed (the uicontrol callback).

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