emaillisting.java

Java程序设计技巧与开发实例附书源代码。

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

public class EmailListing
    extends JFrame
    implements ActionListener, ListSelectionListener {
  private DefaultListModel data = new DefaultListModel();
  private JList list = new JList(data);
  private JTextField name = new JTextField();
  private JTextField email = new JTextField();
  private JButton add = new JButton("Add");
  private JButton del = new JButton("Delete");

  private class WindowCloser
      extends WindowAdapter {
    public void windowClosing(WindowEvent we) {
      System.exit(0);
    }
  }

  public EmailListing() {
    /* defines the basic layout of the GUI components */
    super("Email List");
    JPanel buttons = new JPanel(new FlowLayout());
    buttons.add(add);
    buttons.add(del);
    JPanel input = new JPanel(new GridLayout(2, 2));
    input.add(new JLabel("Name:  "));
    input.add(name);
    input.add(new JLabel("Email: "));
    input.add(email);
    JScrollPane scrollList = new JScrollPane(list);

    getContentPane().add("North", new JPanelBox(input, "Address"));
    getContentPane().add("Center", new JPanelBox(scrollList, "List"));
    getContentPane().add("South", buttons);

    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    list.addListSelectionListener(this);
    add.addActionListener(this);
    del.addActionListener(this);
    email.addActionListener(this);
    addWindowListener(new WindowCloser());
    validate();
    pack();
    setVisible(true);

  }

  public void handleDelete() {
    /* handles deletion of an address selected in the list */
    int tempIndex=list.getSelectedIndex() ;
    if (tempIndex >= 0) {
      data.remove(tempIndex);
    }
  }

  public void handleAdd() {
    /* handles the addition of a new address */
    if (!name.equals("")) {
      data.addElement(new Address(name.getText(), email.getText()));
      name.setText("");
      email.setText("");
      name.requestFocus();
    }
  }

  public void actionPerformed(ActionEvent ae) {
    /* react to action events by calling appropriate handlers */
    if (ae.getSource() == del) {
      handleDelete();
    }
    else if ( (ae.getSource() == add) || (ae.getSource() == email)) {
      handleAdd();
    }
  }

  public void valueChanged(ListSelectionEvent lse) {
    /* displays a 'full' address corresponding to the selected name */
    if (!lse.getValueIsAdjusting()) {
      Address address = (Address) data.get(list.getSelectedIndex());
      name.setText(address.name);
      email.setText(address.email);
    }
  }

  public static void main(String args[]) {
    EmailListing el = new EmailListing();
  }
}