Multi Column JComboBox

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

Code

class MultiColumnCellRenderer extends JPanel implements ListCellRenderer{
  private final JLabel leftLabel = new JLabel();
  private final JLabel rightLabel;
  public MultiColumnCellRenderer(int rightWidth) {
    super(new BorderLayout());
    this.setBorder(BorderFactory.createEmptyBorder(1,1,1,1));

    leftLabel.setOpaque(false);
    leftLabel.setBorder(BorderFactory.createEmptyBorder(0,2,0,0));

    final Dimension dim = new Dimension(rightWidth, 0);
    rightLabel = new JLabel() {
      @Override public Dimension getPreferredSize() {
        return dim;
      }
    };
    rightLabel.setOpaque(false);
    rightLabel.setBorder(BorderFactory.createEmptyBorder(0,2,0,2));
    rightLabel.setForeground(Color.GRAY);
    rightLabel.setHorizontalAlignment(SwingConstants.RIGHT);

    this.add(leftLabel);
    this.add(rightLabel, BorderLayout.EAST);
  }
  @Override public Component getListCellRendererComponent(
      JList list, Object value, int index,
      boolean isSelected, boolean cellHasFocus) {
    LRItem item = (LRItem)value;
    leftLabel.setText(item.getLeftText());
    rightLabel.setText(item.getRightText());

    leftLabel.setFont(list.getFont());
    rightLabel.setFont(list.getFont());

    if(index<0) {
      leftLabel.setForeground(list.getForeground());
      this.setOpaque(false);
    }else{
      leftLabel.setForeground(
          isSelected?list.getSelectionForeground():list.getForeground());
      this.setBackground(
          isSelected?list.getSelectionBackground():list.getBackground());
      this.setOpaque(true);
    }
    return this;
  }
  @Override public Dimension getPreferredSize() {
    Dimension d = super.getPreferredSize();
    return new Dimension(0, d.height);
  }
  @Override public void updateUI() {
    super.updateUI();
    this.setName("List.cellRenderer");
  }
}

References

• Multi Column JComboBox(Japanese)