Putting a button on a tab like in netbeans

Question

In netbeans, the tabbed panes have buttons on the tabs so that you can close a file right there.
Does anyone know how to do this?
Thanks,
LNMEgo

Answer 1

This question has been asked a lot, and I know I saw a handy solution posted recently - you might try a search on this forum. Inspired by the solution I found, I came up with an implementation that allows you to add an Action (which provides the icon and the behavior) to a JTabbedPane tab. It is an extension of JTabbedPane along with an Icon that presents buttons for the added Actions. It could use a little work, but here's the code:
//     ActionableTabbedPane.java
//     A JTabbedPane that supports an ActionTabIcon.
package whatever.package.actiontabs;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class ActionableTabbedPane extends JTabbedPane
     public ActionableTabbedPane()
          super();
          ActionButtonListener abl = new ActionButtonListener();
          addMouseListener(abl);
          addMouseMotionListener(abl);
     public void addTab(String title, Component component, Action action)
          ActionTabIcon icon = new ActionTabIcon();
          icon.addAction(action);
          super.addTab(title, icon, component);
     public void addTab(String title, Component component, Action[] actions)
          ActionTabIcon icon = new ActionTabIcon();
          for (int i=0; i < actions.length; i++)
               icon.addAction(actions);
          super.addTab(title, icon, component);
     private ActionTabIcon findActionTabIconAt(int x, int y)
          int tabNumber = getUI().tabForCoordinate(this, x, y);
          if (tabNumber < 0) return null;
          Icon icon = getIconAt(tabNumber);
          if (icon == null || !(icon instanceof ActionTabIcon)) return null;
          else return (ActionTabIcon)icon;
     private class ActionButtonListener extends MouseInputAdapter
          private ActionTabIcon      nPressedIcon = null;
          public void mousePressed(MouseEvent e)
               int x = e.getX();
               int y = e.getY();
               ActionTabIcon icon = findActionTabIconAt(x, y);
               if (icon != null)
                    nPressedIcon = icon;
                    Rectangle rect = icon.getBounds();
                    icon.showPressed(x - rect.x, y - rect.y);
                    repaint();
          public void mouseReleased(MouseEvent e)
               if (nPressedIcon == null) return;
               nPressedIcon.showReleased();
               nPressedIcon = null;
               repaint();
          public void mouseDragged(MouseEvent e)
               if (nPressedIcon == null) return;
               int x = e.getX();
               int y = e.getY();
               Rectangle rect = nPressedIcon.getBounds();
               nPressedIcon.showDragged(x - rect.x, y - rect.y);
               repaint();
//     ActionTabIcon.java
//     An icon comprised of one or more buttons that can perform an action
//     when clicked. These buttons will be displayed on a tab in a
//     JTabbedPane.
package whatever.package.actiontabs;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
class ActionTabIcon extends JPanel implements Icon
     private JButton          oLastPressedButton = null;
     private int          X = 0,
                    Y = 0;
     public ActionTabIcon()
          // I use a custom layout manager here, but you can use BoxLayout
          setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
          setBorder(BorderFactory.createEmptyBorder(3, 0, 3, 0));
          setOpaque(false);
     public void addAction(Action action)
          JButton jb = new JButton(action);
          jb.setOpaque(false);
          jb.setBorder(null);
          add(jb);
     public JButton getButtonAt(int x, int y)
          Component[] comps = getComponents();
          for (int i=0; i < comps.length; i++)
               Rectangle r = comps[i].getBounds();
               if (r.contains(x, y))
                    return (JButton)comps[i];
          return null;
     public void showPressed(int x, int y)
          JButton b = getButtonAt(x, y);
          oLastPressedButton = b;
          if (b == null) return;
          b.getModel().setPressed(true);
          b.getModel().setArmed(true);
     public void showDragged(int x, int y)
          if (oLastPressedButton == null) return;
          JButton b = getButtonAt(x, y);
          if (b != oLastPressedButton)
               // disarm the last button
               oLastPressedButton.getModel().setArmed(false);
               oLastPressedButton.getModel().setPressed(false);
          else
               // ensure that the last button is armed
               oLastPressedButton.getModel().setPressed(true);
               oLastPressedButton.getModel().setArmed(true);
     public void showReleased()
          Component[] comps = getComponents();
          for (int i=0; i < comps.length; i++)
               JButton b = (JButton)comps[i];
               if (b != null)
                    b.getModel().setPressed(false);
                    b.getModel().setArmed(false);
     public void paintIcon(Component c, Graphics g, int x, int y)
          this.X = x;
          this.Y = y;
          setSize(getPreferredSize());
          g.translate(x, y);
          paintComponent(g);
          paintChildren(g);
          paintBorder(g);
          g.translate(-x, -y);
     protected void paintChildren(Graphics g)
          Component[] c = getComponents();
          doLayout();
          for (int i=0; i < c.length; i++)
               int x = c[i].getX();
               int y = c[i].getY();
               g.translate(x, y);
               c[i].paint(g);
               g.translate(-x, -y);
     public int getIconWidth()
          return getPreferredSize().width;
     public int getIconHeight()
          return getPreferredSize().height;
     public Rectangle getBounds()
          Dimension d = getPreferredSize();
          return new Rectangle(X, Y, d.width, d.height);
//     app.java
//     A test application for the ActionableTabbedPane
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import whatever.package.actiontabs.*;
public class app extends JFrame
     /////////////////////// Main Method ///////////////////////
     public static void main(String[] args)
          if (!(args != null && args.length > 0 &&
                    args[0].equalsIgnoreCase("-plaf")))
               try { UIManager.setLookAndFeel(
                    UIManager.getSystemLookAndFeelClassName()); }
               catch(Exception ex) { }
          new app();
     private ActionableTabbedPane     oTabs = null;
     public app()
          // Set up the JFrame...
          setTitle("Test app");
          setDefaultCloseOperation(EXIT_ON_CLOSE);
          setSize(400, 300);
          setLocationRelativeTo(null);
          Container c = getContentPane();
          c.setLayout(new BorderLayout());
          // Create some actions for the tabs...
          Icon closeIcon = new ImageIcon("docClose.gif");
          Icon saveIcon = new ImageIcon("docSave.gif");
          Icon savedIcon = new ImageIcon("docSaved.gif");
          CloseAction closer = new CloseAction("close", closeIcon);
          SaveAction saver = new SaveAction("save", saveIcon, savedIcon);
          // closer and saver are duplicated/cloned so that changes
          // to the action's icon affect only the associated tab...
          Action[] acts1 = { closer.duplicate(), saver.duplicate() };
          Action[] acts2 = { closer.duplicate(), saver.duplicate() };
          Action[] acts3 = { closer.duplicate(), saver.duplicate() };
          Action[] acts4 = { closer.duplicate(), saver.duplicate() };
          Action[] acts5 = { closer.duplicate(), saver.duplicate() };
          // Create the tabbed pane and add some tabs with panels...
          oTabs = new ActionableTabbedPane();
          // Can't use scroll tab layout due to a bug in 1.4 which
          // blocks mouse events from reaching our custom buttons...
          // // oTabs.setTabLayoutPolicy(oTabs.SCROLL_TAB_LAYOUT);
          oTabs.addTab("Document 1", createPanel(Color.blue), acts1);
          oTabs.addTab("Document 2", createPanel(Color.gray), acts2);
          oTabs.addTab("Document 3", createPanel(Color.yellow), acts3);
          oTabs.addTab("Document 4", createPanel(Color.white), acts4);
          oTabs.addTab("Document 5", createPanel(Color.green), acts5);
          c.add(oTabs, BorderLayout.CENTER);
          setVisible(true);
     private JPanel createPanel(Color bg)
          JPanel p = new JPanel();
          p.setBackground(bg);
          p.setOpaque(true);
          return p;
     private class CloseAction extends AbstractAction
          public CloseAction(String actionCommand, Icon icon)
               super("", icon);
               this.putValue(ACTION_COMMAND_KEY, actionCommand);
          public void actionPerformed(ActionEvent ae)
               if (ae.getActionCommand().equals("close"))
                    oTabs.remove(oTabs.getSelectedIndex());
               System.out.println("Close button fired");
          public CloseAction duplicate()
               String actionCommand = (String)getValue(ACTION_COMMAND_KEY);
               Icon icon = (Icon)getValue(SMALL_ICON);
               return new CloseAction(actionCommand, icon);
     private class SaveAction extends AbstractAction
          private Icon saveIcon = null;
          private Icon savedIcon = null;
          public SaveAction(String actionCommand, Icon save, Icon saved)
               super("");
               saveIcon = save;
               savedIcon = saved;
               this.putValue(this.SMALL_ICON, saved);
               this.putValue(ACTION_COMMAND_KEY, actionCommand);
          public void actionPerformed(ActionEvent ae)
               // Clicking the save button switches icons (just to demonstrate)
               Icon icon = (Icon)this.getValue(SMALL_ICON);
               if (icon == saveIcon) putValue(SMALL_ICON, savedIcon);
               else putValue(SMALL_ICON, saveIcon);
               System.out.println("Save button fired");
          public SaveAction duplicate()
               String actionCommand = (String)getValue(ACTION_COMMAND_KEY);
               return new SaveAction(actionCommand, saveIcon, savedIcon);