App Designer, addlistener for slider

Hi,

I want to update some plots when a slider control is moved, but i want it to update continuously when the slider is dragged. Is it possible to add a listener for the slider in the AppDesigner like with the usual uicontrol, as app.Slider.addlistener('Value', 'PostSet', @(es,ed)update_plot(es,ed,'zeta'));

However, i get an error: Error using matlab.ui.control.Slider/addlistener While adding a PostSet listener, property 'Value' in class 'matlab.ui.control.Slider' is not defined to be SetObservable.

Error in app1 (line 203) runStartupFcn(app, @startupFcn)

Do i have to do it differently?

Sincerely, Rasmus

[Rik]

I suspect the value is only set when you release the slider, so this wouldn't be different from a normal callback.

[Rasmus Steffensen]

But this means it has different implementation than the slider = uicontrol('Style','slider' ... where the above code works fine? how do i get the same functionality with the app designer?

[Adam]

App Designer still has a lot of limitations compared to regular Matlab code or Guide. I guess this is one of them. It seems the 'value' for these sliders is not setup to have observers.

You can use a java slider to achieve continuous callbacks, but it does involve more work and I've never tried including them in App Designer because I 'rage quit' last time I tried to create even a basic UI in App Designer!!

Answer 1

[Madeline Gardner]

Hello!

It looks like App designer has a ValueChanging callback for a slider that gets the value continuously as the slider updates! The syntax is a little different than the code you're referencing, but it should have the same output. This link has some information, but you can also go to callbacks under Slider Properties and select the ValueChangingFcn option. (I've attached just a basic screenshot of what this looks like in the App Designer interface)

Hope that helps!

[Mihail Dadun]

I've encountered the same problem and the ValueChanging (as opposed to ValueChanged) callback still does not provide continuous updates. As in, it updates (the value, implicitly the plot) just once, the only difference being that it does change it before the click release. However, if I keep sliding, it does not produce any results, until I release the click, click again, and briefly slide again. Could this be a bug?

[Raul]

Genius! This works just finely. "value.Event" is the answer!