I have a simple screen made with Nifty gui. On this game screen I want to put a simple image controls sound: just on and not. So I have two images to switch and get music stop or run.

Problem is: how can I hide/disply an image with nifty gui?

Here my java code when player click on image:

    Screen screen = nifty.getCurrentScreen();
    Element el = screen.findElementByName("iconOn");
    el.setVisible(false);
    el = screen.findElementByName("iconOff");
    el.setVisible(true);

This code doesn't work :(

Thanks to everyone could help me