JLayeredPane with a JDialog

问题:

I am unable to make any components apear on a JLayeredPane when adding it to a JDialog.

I have also been unable to find a web resource that shows this may be done in a reasonably sized block of code. Every sight iv looked at "claims" this can be done, and then shows a disgustingly long solution.

What i want is to take a JLayered pane add a Button and place a JLabel with an icon in it onto this pane aswell. In english i want a button with an icon stuck in the front of its text.

That is the awt Button as I have been unable to find a way of making a system looking swing JButton.

Edit: could you help me out with something a little more specific. I think I was a littile to vague in my post.

Button button = new Button("ok");
JDialog dialog = new JDialog(null,"Windows",Dialog.ModalityType.APPLICATION_MODAL);
dialog.getLayeredPane().add(button);
dialog.pack();
dialog.setVisible(true);

回答1:

I don't seem to have any issues...

public class TestLayeredDialog {

    public static void main(String[] args) {
        new TestLayeredDialog();
    }

    public TestLayeredDialog() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JDialog dialog = new JDialog();
                dialog.setModal(true);
                dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
                dialog.setLayout(new BorderLayout());
                dialog.add(new MyContent());
                dialog.pack();
                dialog.setLocationRelativeTo(null);
                dialog.setVisible(true);

                System.exit(0);
            }
        });
    }

    public class MyContent extends JLayeredPane {

        public MyContent() {
            JLabel label = new JLabel("Hello new world");
            label.setSize(label.getPreferredSize());
            label.setLocation(0, 0);
            add(label);

            Dimension size = getPreferredSize();

            JButton button = new JButton("Click me");
            button.setSize(button.getPreferredSize());
            button.setLocation(size.width - button.getWidth(), size.height - button.getHeight());
            button.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    SwingUtilities.getWindowAncestor(MyContent.this).dispose();
                }
            });
            add(button);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

    }

}

Remember, JLayeredPane DOES NOT have a layout manager. You become responsible for managing the size and position of the child components, that's the point.

Updated with new example

public class TestLayeredDialog {

    public static void main(String[] args) {
        new TestLayeredDialog();
    }

    public TestLayeredDialog() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JDialog dialog = new JDialog();
                dialog.setModal(true);
                dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
                dialog.setLayout(new BorderLayout());

                JLabel label = new JLabel("Hello new world");
                label.setSize(label.getPreferredSize());
                label.setLocation(0, 0);
                dialog.getLayeredPane().add(label, new Integer(1));

                dialog.setSize(100, 100);
                dialog.setLocationRelativeTo(null);
                dialog.setVisible(true);

                System.exit(0);
            }
        });
    }
}

The layered pane of the JRootPane is responsible for (amongst other things) laying out the content pane and menu bar. It is also used (in some cases) to display things like popups.

Have a read through How to Use Root Panes

You can choose to put components in the root pane's layered pane. If you do, then you should be aware that certain depths are defined to be used for specific functions, and you should use the depths as intended. Otherwise, your components might not play well with the others. Here's a diagram that shows the functional layers and their relationship:

Using this, means you are competing with components already on the screen.

Unless you have VERY good reason to be messing with this component, I would suggest you avoid it as 1- It's possible to be changed in the future (the layer position of the components) and 2- It may interfere with other components used by the Swing API

回答2:

This example seems to work with the following lines added to the constructor:

this.addMouseListener(new MouseHandler(this));
this.add(new JLabel("Label"));
this.add(new JButton(UIManager.getIcon("html.pendingImage")));