Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;

import javax.swing.AbstractAction;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLayer;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.WindowConstants;
import javax.swing.plaf.LayerUI;

public class Main {
    public JComponent makeUI() {
        UIManager.put("TabbedPane.tabInsets", new Insets(2, 2, 2, 50));
        final JTabbedPane tabbedPane = new JTabbedPane();
        tabbedPane.addTab("A", new JPanel());

        JPanel p = new JPanel(new BorderLayout());
        p.add(new JLayer<JTabbedPane>(tabbedPane, new CloseableTabbedPaneLayerUI()));
        p.add(new JButton(new AbstractAction("add tab") {
            @Override
            public void actionPerformed(ActionEvent e) {
                tabbedPane.addTab("test", new JPanel());
            }
        }), BorderLayout.SOUTH);
        return p;
    }

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        f.getContentPane().add(new Main().makeUI());
        f.setSize(320, 240);
        f.setVisible(true);
    }
}

class MyCloseButton extends JButton {
    public MyCloseButton() {
        super("x");
        setBorder(BorderFactory.createEmptyBorder());
        setFocusPainted(false);
        setBorderPainted(false);
        setContentAreaFilled(false);
        setRolloverEnabled(false);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(16, 16);
    }
};

class CloseableTabbedPaneLayerUI extends LayerUI<JTabbedPane> {
    JPanel p = new JPanel();
    Point pt = new Point(-100, -100);
    MyCloseButton button = new MyCloseButton();

    public CloseableTabbedPaneLayerUI() {
        super();
    }

    @Override
    public void paint(Graphics g, JComponent c) {
        super.paint(g, c);
        if (c instanceof JLayer == false) {
            return;
        }
        JLayer jlayer = (JLayer) c;
        JTabbedPane tabPane = (JTabbedPane) jlayer.getView();
        for (int i = 0; i < tabPane.getTabCount(); i++) {
            Rectangle rect = tabPane.getBoundsAt(i);
            Dimension d = button.getPreferredSize();
            int x = rect.x + rect.width - d.width - 2;
            int y = rect.y + (rect.height - d.height) / 2;
            Rectangle r = new Rectangle(x, y, d.width, d.height);
            button.setForeground(r.contains(pt) ? Color.RED : Color.BLACK);
            SwingUtilities.paintComponent(g, button, p, r);
        }
    }

    @Override
    public void installUI(JComponent c) {
        super.installUI(c);
        ((JLayer) c).setLayerEventMask(AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK);
    }

    @Override
    public void uninstallUI(JComponent c) {
        ((JLayer) c).setLayerEventMask(0);
        super.uninstallUI(c);
    }

    @Override
    protected void processMouseEvent(MouseEvent e, JLayer<? extends JTabbedPane> l) {
        if (e.getID() != MouseEvent.MOUSE_CLICKED) {
            return;
        }
        pt.setLocation(e.getPoint());
        JTabbedPane tabbedPane = (JTabbedPane) l.getView();
        int index = tabbedPane.indexAtLocation(pt.x, pt.y);
        if (index >= 0) {
            Rectangle rect = tabbedPane.getBoundsAt(index);
            Dimension d = button.getPreferredSize();
            int x = rect.x + rect.width - d.width - 2;
            int y = rect.y + (rect.height - d.height) / 2;
            Rectangle r = new Rectangle(x, y, d.width, d.height);
            if (r.contains(pt)) {
                tabbedPane.removeTabAt(index);
            }
        }
        l.getView().repaint();
    }

    @Override
    protected void processMouseMotionEvent(MouseEvent e, JLayer<? extends JTabbedPane> l) {
        pt.setLocation(e.getPoint());
        JTabbedPane tabbedPane = (JTabbedPane) l.getView();
        int index = tabbedPane.indexAtLocation(pt.x, pt.y);
        if (index >= 0) {
            tabbedPane.repaint(tabbedPane.getBoundsAt(index));
        } else {
            tabbedPane.repaint();
        }
    }
}