JRootpane - setting glasspane to visible doesnt intercept mouse events

Question

I have a JFrame and a JPanel hierarchy inside it, i want to implement an inner panel that i can make it look "disabled"(while other panels dont change), that is, to cover it by a semi transparent gray layer and intercept all mouse and perhaps even keyboard events that are dispatched to this panel. ive been searching for a solution and didnt really find a good one yet.

The closest i got to a solution was when i used JRootPane, whenever i want it disabled i make its glasspane visible. the glasspane had been set to be opaque and with semi transparent background.

A simple example of my attempt :

public class Test extends JFrame {
    private final JPanel jPanel;

    public Test() {
        jPanel = new JPanel();
        final JButton jButton = new JButton("Hidden");
        jButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("hidden is clicked!");
            }
        });
        final JRootPane jRootPane = new JRootPane();
        jPanel.add(jRootPane);
        final JPanel glassPane = new JPanel();
        final JButton jButton2 = new JButton();
        jButton2.addActionListener(new ActionListener() {
            private boolean visible = true;

            @Override
            public void actionPerformed(ActionEvent e) {
                glassPane.setVisible(visible = !visible);
            }
        });
        jPanel.add(jButton2);

        jRootPane.getContentPane().add(new JScrollPane(jButton));
        glassPane.setBackground(new Color(0.5f, 0.5f, 0.5f, 0.2f));
        glassPane.setOpaque(true);
        jRootPane.setGlassPane(glassPane);
        glassPane.setVisible(true);
        getContentPane().add(jPanel);    
    }

    public static void main(String[] strings) {
        final Test test = new Test();
        test.pack();
        test.setVisible(true);
    }    
}

But the problem is that even when the glass is visible on top of the content, it doesnt intercepts events from getting to the content as it should, as documented here.

@CatalinaIsland because i dont want the whole frame to be disabled only the specicific jpanel — Ofek Ron, Nov 03 '14 at 12:31
@Catalina Island [e.g](http://stackoverflow.com/a/9734016/714968) — mKorbel, Nov 03 '14 at 14:39

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

In your test class your glasspane doesn't intercept events, because you didn't tell it to intercept events (intercepting events is not a default behavior).

In the documentation link, it says

The glass pane

The glass pane is useful when you want to be able to catch events or paint over an area that already contains one or more components. For example, you can deactivate mouse events for a multi-component region by having the glass pane intercept the events. Or you can display an image over multiple components using the glass pane.

You can intercept Mouse Events this way:

    glassPane.addMouseListener(new MouseAdapter()
    {
        @Override
        public void mouseClicked(MouseEvent e)
        {
            e.consume();
        }

        @Override
        public void mousePressed(MouseEvent e)
        {
            e.consume();
        }
    });

You can intercept KeyBoard Events this way:

    glassPane.setFocusable(true);
    glassPane.addKeyListener(new KeyListener()
    {
        @Override
        public void keyTyped(KeyEvent e)
        {
            e.consume();
        }

        @Override
        public void keyReleased(KeyEvent e)
        {
            e.consume();
        }

        @Override
        public void keyPressed(KeyEvent e)
        {
            e.consume();
        }
    });

Note: The JPanel has to be focasable to intercept the keyboard events.

They did nothing like that on their example :http://docs.oracle.com/javase/tutorial/displayCode.html?code=http://docs.oracle.com/javase/tutorial/uiswing/examples/components/GlassPaneDemoProject/src/components/GlassPaneDemo.java — Ofek Ron, Nov 05 '14 at 09:56
@Ofek Ron The java documentation example is about painting on the glass pane. If you see the 'MyGlassPane' class, they have 'CBListener' which listens to mouse clicks and draws an 'oval' on the GlassPane. But as per you question : **to cover it by a semi transparent gray layer and intercept all mouse and perhaps even keyboard events that are dispatched to this panel**. If you need to block the events, you need to 'consume' them. — always_a_rookie, Nov 05 '14 at 12:39

JRootpane - setting glasspane to visible doesnt intercept mouse events

1 Answers1