Add header and footer in the JComboBox dropdown list

• download example.jar
• download src.zip
• repository

Add the header created by JLabel and the clickable footer created by JMenuItem in the drop-down list of JComboBox

Code

class HeaderFooterComboPopup extends BasicComboPopup {
  protected transient JLabel header;
  protected transient JMenuItem footer;

  public HeaderFooterComboPopup(JComboBox combo) {
    super(combo);
  }

  @Override protected void configurePopup() {
    super.configurePopup();
    configureHeader();
    configureFooter();
    add(header, 0);
    add(footer);
  }

  protected void configureHeader() {
    header = new JLabel("History");
    header.setBorder(BorderFactory.createEmptyBorder(4, 5, 4, 0));
    header.setMaximumSize(new Dimension(Short.MAX_VALUE, 20));
    header.setAlignmentX(1f);
  }

  protected void configureFooter() {
    int modifiers = InputEvent.CTRL_DOWN_MASK | InputEvent.SHIFT_DOWN_MASK;
    footer = new JMenuItem("Show All Bookmarks");
    footer.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_B, modifiers));
    footer.addActionListener(e -> {
      Window w = SwingUtilities.getWindowAncestor(getInvoker());
      JOptionPane.showMessageDialog(w, "Bookmarks");
    });
  }
}

References

• Add header and footer in the JComboBox dropdown list(Japanese)

Use JTable instead of JList as a drop down list of JComboBox

• download example.jar
• download src.zip
• repository

Code

class DropdownTableComboBox<E extends List<Object>> extends JComboBox<E> {
  protected final transient HighlightListener highlighter = new HighlightListener();
  protected final JTable table = new JTable() {
    @Override public Component prepareRenderer(
          TableCellRenderer renderer, int row, int column) {
      Component c = super.prepareRenderer(renderer, row, column);
      c.setForeground(Color.BLACK);
      if (highlighter.isHighlightableRow(row)) {
        c.setBackground(new Color(255, 200, 200));
      } else if (isRowSelected(row)) {
        c.setBackground(Color.CYAN);
      } else {
        c.setBackground(Color.WHITE);
      }
      return c;
    }
    @Override public void updateUI() {
      removeMouseListener(highlighter);
      removeMouseMotionListener(highlighter);
      super.updateUI();
      addMouseListener(highlighter);
      addMouseMotionListener(highlighter);
      getTableHeader().setReorderingAllowed(false);
    }
  };
  protected final List<E> list;

  protected DropdownTableComboBox(List<E> list, DefaultTableModel model) {
    super();
    this.list = list;
    table.setModel(model);
    list.forEach(this::addItem);
    // list.forEach(model::addRow);
    list.forEach(v -> model.addRow(v.toArray(new Object[0])));
  }

  @Override public void updateUI() {
    super.updateUI();
    EventQueue.invokeLater(() -> {
      setUI(new MetalComboBoxUI() {
        @Override protected ComboPopup createPopup() {
          return new ComboTablePopup(comboBox, table);
        }
      });
      setEditable(false);
    });
  }
  public List<Object> getSelectedRow() {
    return list.get(getSelectedIndex());
  }
}

References

• Use JTable instead of JList as a drop down list of JComboBox(Japanese)

Delete button in a JComboBox popup menu items

• download example.jar
• download src.zip
• repository

Code

class CellButtonsMouseListener extends MouseAdapter {
  @Override public void mouseMoved(MouseEvent e) {
    JList<?> list = (JList<?>) e.getComponent();
    Point pt = e.getPoint();
    int index = list.locationToIndex(pt);
    ButtonsRenderer<?> renderer = (ButtonsRenderer<?>) list.getCellRenderer();
    renderer.rolloverIndex = Objects.nonNull(getButton(list, pt, index)) ? index : -1;
    list.repaint();
  }

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

  @Override public void mouseReleased(MouseEvent e) {
    JList<?> list = (JList<?>) e.getComponent();
    Point pt = e.getPoint();
    int index = list.locationToIndex(pt);
    if (index >= 0) {
      JButton button = getButton(list, pt, index);
      if (Objects.nonNull(button)) {
        button.doClick();
      }
    }
    ((ButtonsRenderer<?>) list.getCellRenderer()).rolloverIndex = -1;
    list.repaint();
  }

  @Override public void mouseExited(MouseEvent e) {
    JList<?> list = (JList<?>) e.getComponent();
    ((ButtonsRenderer<?>) list.getCellRenderer()).rolloverIndex = -1;
  }

  private static <E> JButton getButton(JList<E> list, Point pt, int index) {
    E proto = list.getPrototypeCellValue();
    Component c = list.getCellRenderer().getListCellRendererComponent(
        list, proto, index, false, false);
    Rectangle r = list.getCellBounds(index, index);
    c.setBounds(r);
    // c.doLayout(); // may be needed for other layout managers (eg. FlowLayout)
    pt.translate(-r.x, -r.y);
    return Optional.ofNullable(SwingUtilities.getDeepestComponentAt(c, pt.x, pt.y))
        .filter(JButton.class::isInstance).map(JButton.class::cast).orElse(null);
  }
}

References

• Delete button in a JComboBox popup menu items(Japanese)

Disable Right Click In JComboBox-Dropdown-List

• download example.jar
• download src.zip
• repository

Code

class BasicComboPopup2 extends BasicComboPopup {
  private transient Handler2 handler2;

  public BasicComboPopup2(JComboBox combo) {
    super(combo);
  }

  @Override public void uninstallingUI() {
    super.uninstallingUI();
    handler2 = null;
  }

  @Override protected MouseListener createListMouseListener() {
    if (handler2 == null) {
      handler2 = new Handler2();
    }
    return handler2;
  }

  private class Handler2 extends MouseAdapter {
    @Override public void mouseReleased(MouseEvent e) {
      if (e.getSource().equals(list)) {
        if (list.getModel().getSize() > 0) {
          // <ins>
          if (!SwingUtilities.isLeftMouseButton(e) ||
              !comboBox.isEnabled()) {
            return;
          }
          // </ins>
          // JList mouse listener
          if (comboBox.getSelectedIndex() == list.getSelectedIndex()) {
            comboBox.getEditor().setItem(list.getSelectedValue());
          }
          comboBox.setSelectedIndex(list.getSelectedIndex());
        }
        comboBox.setPopupVisible(false);
        // workaround for cancelling an edited item (bug 4530953)
        if (comboBox.isEditable() && comboBox.getEditor() != null) {
          comboBox.configureEditor(
              comboBox.getEditor(), comboBox.getSelectedItem());
        }
      }
    }
  }
}

References

• Disable Right Click In JComboBox-Dropdown-List(Japanese)