Java Swing How to - Extend JList to create checkbox list

Question

We would like to know how to extend JList to create checkbox list.
Answer

import java.awt.Color;
import java.awt.Component;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
//  www.  jav a 2  s. c  o  m
import javax.swing.DefaultListCellRenderer;
import javax.swing.DefaultListModel;
import javax.swing.JCheckBox;
import javax.swing.JList;
import javax.swing.ListSelectionModel;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;

public class CheckBoxList extends JList {

  public CheckBoxList() {
    super();

    setModel(new DefaultListModel());
    setCellRenderer(new CheckboxCellRenderer());

    addMouseListener(new MouseAdapter() {
      @Override
      public void mousePressed(MouseEvent e) {
        int index = locationToIndex(e.getPoint());

        if (index != -1) {
          Object obj = getModel().getElementAt(index);
          if (obj instanceof JCheckBox) {
            JCheckBox checkbox = (JCheckBox) obj;

            checkbox.setSelected(!checkbox.isSelected());
            repaint();
          }
        }
      }
    }

    );

    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
  }

  @SuppressWarnings("unchecked")
  public int[] getCheckedIdexes() {
    java.util.List list = new java.util.ArrayList();
    DefaultListModel dlm = (DefaultListModel) getModel();
    for (int i = 0; i < dlm.size(); ++i) {
      Object obj = getModel().getElementAt(i);
      if (obj instanceof JCheckBox) {
        JCheckBox checkbox = (JCheckBox) obj;
        if (checkbox.isSelected()) {
          list.add(new Integer(i));
        }
      }
    }

    int[] indexes = new int[list.size()];

    for (int i = 0; i < list.size(); ++i) {
      indexes[i] = ((Integer) list.get(i)).intValue();
    }

    return indexes;
  }

  @SuppressWarnings("unchecked")
  public java.util.List getCheckedItems() {
    java.util.List list = new java.util.ArrayList();
    DefaultListModel dlm = (DefaultListModel) getModel();
    for (int i = 0; i < dlm.size(); ++i) {
      Object obj = getModel().getElementAt(i);
      if (obj instanceof JCheckBox) {
        JCheckBox checkbox = (JCheckBox) obj;
        if (checkbox.isSelected()) {
          list.add(checkbox);
        }
      }
    }
    return list;
  }
}

/*
 * Copyright (C) 2005 - 2007 JasperSoft Corporation. All rights reserved.
 * http://www.jaspersoft.com.
 * 
 * Unless you have purchased a commercial license agreement from JasperSoft, the
 * following license terms apply:
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 * 
 * This program is distributed WITHOUT ANY WARRANTY; and without the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see http://www.gnu.org/licenses/gpl.txt or write to:
 * 
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA USA
 * 02111-1307
 * 
 * 
 * 
 * 
 * CheckboxCellRenderer.java
 * 
 * Created on October 5, 2006, 10:03 AM
 * 
 */

/**
 * 
 * @author gtoffoli
 */
class CheckboxCellRenderer extends DefaultListCellRenderer {
  protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);

  public Component getListCellRendererComponent(JList list, Object value, int index,
      boolean isSelected, boolean cellHasFocus) {
    if (value instanceof CheckBoxListEntry) {
      CheckBoxListEntry checkbox = (CheckBoxListEntry) value;
      checkbox.setBackground(isSelected ? list.getSelectionBackground() : list.getBackground());
      if (checkbox.isRed()) {
        checkbox.setForeground(Color.red);
      } else {
        checkbox.setForeground(isSelected ? list.getSelectionForeground() : list.getForeground());
      }
      checkbox.setEnabled(isEnabled());
      checkbox.setFont(getFont());
      checkbox.setFocusPainted(false);
      checkbox.setBorderPainted(true);
      checkbox.setBorder(isSelected ? UIManager.getBorder("List.focusCellHighlightBorder")
          : noFocusBorder);

      return checkbox;
    } else {
      return super.getListCellRendererComponent(list, value.getClass().getName(), index,
          isSelected, cellHasFocus);
    }
  }
}

/*
 * Copyright (C) 2005 - 2007 JasperSoft Corporation. All rights reserved.
 * http://www.jaspersoft.com.
 * 
 * Unless you have purchased a commercial license agreement from JasperSoft, the
 * following license terms apply:
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 * 
 * This program is distributed WITHOUT ANY WARRANTY; and without the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see http://www.gnu.org/licenses/gpl.txt or write to:
 * 
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA USA
 * 02111-1307
 * 
 * 
 * 
 * 
 * CheckBoxListEntry.java
 * 
 * Created on October 5, 2006, 10:19 AM
 * 
 */

/**
 * 
 * @author gtoffoli
 */
class CheckBoxListEntry extends JCheckBox {

  private Object value = null;

  private boolean red = false;

  public CheckBoxListEntry(Object itemValue, boolean selected) {
    super(itemValue == null ? "" : "" + itemValue, selected);
    setValue(itemValue);
  }

  public boolean isSelected() {
    return super.isSelected();
  }

  public void setSelected(boolean selected) {
    super.setSelected(selected);
  }

  public Object getValue() {
    return value;
  }

  public void setValue(Object value) {
    this.value = value;
  }

  public boolean isRed() {
    return red;
  }

  public void setRed(boolean red) {
    this.red = red;
  }

}