How do I set my frames to Borderless Fullscreen, Windowed Fullscreen, and Fullscreen in Java?

Question

I use GraphicsDevice to fullscreen my Java Window, but I don't know how to change these settings while the application is running.

public void act(java.awt.Frame window) {
        if (state == SCREEN.FULLSCREEN) {
            if (ev.isFullScreenSupported()) {
                isFullScreen = true;
                window.dispose();
                ev.setFullScreenWindow(window);
                window.setVisible(true);
            }
        }
        if (state == SCREEN.WINDOWED) {
            isFullScreen = false;
            window.dispose();
            ev.setFullScreenWindow(null);
            window.setUndecorated(false);
            window.setVisible(true);
        }
        if (state == SCREEN.BORDERLESS) {
            isFullScreen = true;
            window.dispose();
            ev.setFullScreenWindow(null);
            window.setUndecorated(true);
            window.setVisible(true);
        }
    }

When I run this infinitely, the code just creates a new window over and over, but I want to make it so that the screen changes depending on the value of state.

Answer 1

Although I had to change the parameters around, it was rather simple. For the fields, you need:

    public enum ScreenState {
        fullscreen, borderless, windowed, none
    };
    public static ScreenState current;
    private static GraphicsEnvironment env = 
    GraphicsEnvironment.getLocalGraphicsEnvironment();
    private static GraphicsDevice ev = env.getDefaultScreenDevice();

And for the method you can do something like:

public void changeWindow(ScreenState applied, JFrame frame) {

        if (applied == ScreenState.fullscreen && current != ScreenState.fullscreen) {
            if (ev.isFullScreenSupported()) {
                ev.setFullScreenWindow(frame);
            }
            current =  ScreenState.fullscreen;
        }
        if (applied == ScreenState.borderless && current != ScreenState.borderless) {
            frame.setUndecorated(true);
            frame.setExtendedState(Frame.MAXIMIZED_BOTH);
            current =  ScreenState.borderless;
        }
        if (applied == ScreenState.windowed && current != ScreenState.windowed) {
            frame.setUndecorated(false);
            // you can choose to make the screen fit or not
            frame.setExtendedState(Frame.MAXIMIZED_BOTH);
            current =  ScreenState.windowed;
        }
    }

Thank you for the ones spending some time to help me out!