import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

/*
Demo modified from Walrath and Campione's ListDemo.java in The JFC
Swing Tutorial: Java 2 Platform, Addison Wesley 1999 that is initially
empty and can contain JLabels as items.  Note the use of of labels
that contain icons and a ListCellRender for displaying the labels.
Select an item, its text value is in the bottom textfield.  Change the
textfield and press "update".  The updated item will have a new icon
as well as a change in the text.

mike barnes
9/12/02
*/

public class LabelList  extends JFrame
                        implements ListSelectionListener {
  private JList list;
  private DefaultListModel listModel;

  private JPanel panel;

  private static final String addString = "Add ";
  private static final String doneString = "Done";
  private static final String updateString = "Update";
  private JButton addButton, doneButton, updateButton;
  private JTextField textValue;
  private static ImageIcon left = new ImageIcon("left.gif");
  private static ImageIcon middle = new ImageIcon("middle.gif");

  public LabelList() {
    super("To Do Demo");

    listModel = new DefaultListModel();
    MyCellRenderer render = new MyCellRenderer();

    //Create the list and put it in a scroll pane
    list = new JList(listModel);
    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    list.addListSelectionListener(this);
    list.setCellRenderer(render);
    JScrollPane listScrollPane = new JScrollPane(list);
   
    addButton = new JButton(addString);
    addButton.setActionCommand(addString);
    addButton.addActionListener(new AddListener());

    doneButton = new JButton("Done");
    doneButton.setActionCommand(doneString);
    doneButton.setEnabled(false);
    doneButton.addActionListener(new DoneListener());

    updateButton = new JButton("Update");
    updateButton.setActionCommand(updateString);
    updateButton.setEnabled(false);
    updateButton.addActionListener(new UpdateListener());

    textValue = new JTextField(10);
    textValue.addActionListener(new AddListener());
    textValue.setText("");

    //Create a panel that uses FlowLayout (the default).
    JPanel buttonPane = new JPanel();
    buttonPane.add(textValue);
    buttonPane.add(addButton);
    buttonPane.add(doneButton);
    buttonPane.add(updateButton);

    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());
    listScrollPane.setPreferredSize(new Dimension(300, 200));
    contentPane.add(listScrollPane, BorderLayout.CENTER);
    contentPane.add(buttonPane, BorderLayout.SOUTH);
    System.out.println("selected position is " + list.getSelectedIndex());
    }

  class UpdateListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {

      JLabel label = (JLabel) list.getSelectedValue();
      label.setIcon(middle);
      label.setText(textValue.getText());
      int index = list.getSelectedIndex();
      listModel.remove(index);
      listModel.insertElementAt(label, index);
      list.setSelectedIndex(index);
   }
  }

  class DoneListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      // This method can be called only if there's a valid selection
      // so go ahead and remove whatever's selected.
      JLabel label;
      int index = list.getSelectedIndex();
      label = (JLabel) listModel.remove(index);

      int size = listModel.getSize();
      if (size == 0) {
          // Nobody's left, disable firing.
          textValue.setText("");
          doneButton.setEnabled(false);
          updateButton.setEnabled(false); } 
        else {
          //Adjust the selection.
          if (index == listModel.getSize()) //removed item in last position
            index--;
          list.setSelectedIndex(index);}   //otherwise select same index
      }
    }

  //This listener is shared by the text field and the Add button
  class AddListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {

      //User didn't type in a name...
      if (textValue.getText().equals("")) {
        Toolkit.getDefaultToolkit().beep();
        return;
      }

      int index = list.getSelectedIndex();
      int size = listModel.getSize();

      JLabel label = new JLabel(textValue.getText(), left, JLabel.LEFT );

      //If no selection or if item in last position is selected,
      //add the new hire to end of list, and select new hire.
      if (index == -1 || (index+1 == size)) {
        listModel.addElement(label);
        list.setSelectedIndex(size);

      //Otherwise insert the new hire after the current selection,
      //and select new hire.
      } else {
        listModel.insertElementAt(label, index+1);
        list.setSelectedIndex(index+1);
      }
     System.out.println("added position is " +  list.getSelectedIndex());
    }
  }


  public void valueChanged(ListSelectionEvent e) {
    if (e.getValueIsAdjusting() == false) {

      if (list.getSelectedIndex() == -1) {
      //No selection, disable fire button.
        doneButton.setEnabled(false);
        updateButton.setEnabled(false);
        textValue.setText("");

      } else {  //Selection, update text field.
        JLabel label = (JLabel) list.getSelectedValue();
        updateButton.setEnabled(true);
        doneButton.setEnabled(true);
        textValue.setText(label.getText());
      }
    }
  }

  public static void main(String s[]) {
    JFrame frame = new LabelList();

    frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
    frame.pack();
    frame.setVisible(true);
  }

//  Here is the ListCellRender
class MyCellRenderer extends JLabel implements ListCellRenderer {
  public MyCellRenderer() {
    setOpaque(true);
    }
  public Component getListCellRendererComponent (
    JList list, Object value, int index, boolean isSelected,
    boolean cellHasFocus) {

   if (isSelected) {
      setBackground(list.getSelectionBackground());
      setForeground(list.getSelectionForeground()); }
    else {
      setBackground(list.getBackground());
      setForeground(list.getForeground());}
            
  JLabel l = (JLabel)value;
    ImageIcon icon = (ImageIcon) l.getIcon();
    setText(l.getText());
    setIcon(icon);
    return this;
    }
  }

}