JTabbedPane（6）

import javax.swing.*;
import javax.swing.*;
import javax.swing.plaf.basic.BasicButtonUI;
import java.awt.*;
import java.awt.event.*;

/**
* Component to be used as tabComponent;
* Contains a JLabel to show the text and
* a JButton to close the tab it belongs to
*/
public class ButtonTabComponent extends JPanel {
private final JTabbedPane pane;

public ButtonTabComponent(final JTabbedPane pane) {
//unset default FlowLayout' gaps
super(new FlowLayout(FlowLayout.LEFT, 0, 0));
if (pane == null) {
throw new NullPointerException("TabbedPane is null");
}
this.pane = pane;
setOpaque(false);

//make JLabel read titles from JTabbedPane
JLabel label = new JLabel() {
public String getText() {
int i = pane.indexOfTabComponent(ButtonTabComponent.this);
if (i != -1) {
return pane.getTitleAt(i);
}
return null;
}
};

add(label);
//add more space between the label and the button
label.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 5));
//tab button
JButton button = new TabButton();
add(button);
//add more space to the top of the component
setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 0));
}

private class TabButton extends JButton implements ActionListener {
public TabButton() {
int size = 17;
setPreferredSize(new Dimension(size, size));
setToolTipText("close this tab");
//Make the button looks the same for all Laf's
setUI(new BasicButtonUI());
//Make it transparent
setContentAreaFilled(false);
//No need to be focusable
setFocusable(false);
setBorder(BorderFactory.createEtchedBorder());
setBorderPainted(false);
//Making nice rollover effect
//we use the same listener for all buttons
addMouseListener(buttonMouseListener);
setRolloverEnabled(true);
//Close the proper tab by clicking the button
addActionListener(this);
}

public void actionPerformed(ActionEvent e) {
int i = pane.indexOfTabComponent(ButtonTabComponent.this);
if (i != -1) {
pane.remove(i);
}
}

//we don't want to update UI for this button
public void updateUI() {
}

//paint the cross
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g.create();
//shift the image for pressed buttons
if (getModel().isPressed()) {
g2.translate(1, 1);
}
g2.setStroke(new BasicStroke(2));
g2.setColor(Color.BLACK);
if (getModel().isRollover()) {
g2.setColor(Color.MAGENTA);
}
int delta = 6;
g2.drawLine(delta, delta, getWidth() - delta - 1, getHeight() - delta - 1);
g2.drawLine(getWidth() - delta - 1, delta, delta, getHeight() - delta - 1);
g2.dispose();
}
}

private final static MouseListener buttonMouseListener = new MouseAdapter() {
public void mouseEntered(MouseEvent e) {
Component component = e.getComponent();
if (component instanceof AbstractButton) {
AbstractButton button = (AbstractButton) component;
button.setBorderPainted(true);
}
}

public void mouseExited(MouseEvent e) {
Component component = e.getComponent();
if (component instanceof AbstractButton) {
AbstractButton button = (AbstractButton) component;
button.setBorderPainted(false);
}
}
};
}