ListTest.java Source code

Introduction

Here is the source code for ListTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even 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/>.
*/

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

/**
 * This program demonstrates a simple fixed list of strings.
 * @version 1.23 2007-08-01
 * @author Cay Horstmann
 */
public class ListTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new ListFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * This frame contains a word list and a label that shows a sentence made up from the chosen words.
 * Note that you can select multiple words with Ctrl+click and Shift+click.
 */
class ListFrame extends JFrame {
    public ListFrame() {
        setTitle("ListTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        String[] words = { "quick", "brown", "hungry", "wild", "silent", "huge", "private", "abstract", "static",
                "final" };

        wordList = new JList(words);
        wordList.setVisibleRowCount(4);
        JScrollPane scrollPane = new JScrollPane(wordList);

        listPanel = new JPanel();
        listPanel.add(scrollPane);
        wordList.addListSelectionListener(new ListSelectionListener() {
            public void valueChanged(ListSelectionEvent event) {
                Object[] values = wordList.getSelectedValues();

                StringBuilder text = new StringBuilder(prefix);
                for (int i = 0; i < values.length; i++) {
                    String word = (String) values[i];
                    text.append(word);
                    text.append(" ");
                }
                text.append(suffix);

                label.setText(text.toString());
            }
        });

        buttonPanel = new JPanel();
        group = new ButtonGroup();
        makeButton("Vertical", JList.VERTICAL);
        makeButton("Vertical Wrap", JList.VERTICAL_WRAP);
        makeButton("Horizontal Wrap", JList.HORIZONTAL_WRAP);

        add(listPanel, BorderLayout.NORTH);
        label = new JLabel(prefix + suffix);
        add(label, BorderLayout.CENTER);
        add(buttonPanel, BorderLayout.SOUTH);
    }

    /**
     * Makes a radio button to set the layout orientation.
     * @param label the button label
     * @param orientation the orientation for the list
     */
    private void makeButton(String label, final int orientation) {
        JRadioButton button = new JRadioButton(label);
        buttonPanel.add(button);
        if (group.getButtonCount() == 0)
            button.setSelected(true);
        group.add(button);
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                wordList.setLayoutOrientation(orientation);
                listPanel.revalidate();
            }
        });
    }

    private static final int DEFAULT_WIDTH = 400;
    private static final int DEFAULT_HEIGHT = 300;
    private JPanel listPanel;
    private JList wordList;
    private JLabel label;
    private JPanel buttonPanel;
    private ButtonGroup group;
    private String prefix = "The ";
    private String suffix = "fox jumps over the lazy dog.";
}