JTextFieldSample.java Source code

Introduction

Here is the source code for JTextFieldSample.java

Source

/*
Definitive Guide to Swing for Java 2, Second Edition
By John Zukowski       
ISBN: 1-893115-78-X
Publisher: APress
*/

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;

public class JTextFieldSample {
    public static void main(String args[]) {
        String title = (args.length == 0 ? "TextField Listener Example" : args[0]);
        JFrame frame = new JFrame(title);
        Container content = frame.getContentPane();

        JPanel namePanel = new JPanel(new BorderLayout());
        JLabel nameLabel = new JLabel("Name: ");
        nameLabel.setDisplayedMnemonic(KeyEvent.VK_N);
        JTextField nameTextField = new JTextField();
        nameLabel.setLabelFor(nameTextField);
        namePanel.add(nameLabel, BorderLayout.WEST);
        namePanel.add(nameTextField, BorderLayout.CENTER);
        content.add(namePanel, BorderLayout.NORTH);

        JPanel cityPanel = new JPanel(new BorderLayout());
        JLabel cityLabel = new JLabel("City: ");
        cityLabel.setDisplayedMnemonic(KeyEvent.VK_C);
        JTextField cityTextField = new JTextField();
        cityLabel.setLabelFor(cityTextField);
        cityPanel.add(cityLabel, BorderLayout.WEST);
        cityPanel.add(cityTextField, BorderLayout.CENTER);
        content.add(cityPanel, BorderLayout.SOUTH);

        ActionListener actionListener = new ActionListener() {
            public void actionPerformed(ActionEvent actionEvent) {
                System.out.println("Command: " + actionEvent.getActionCommand());
            }
        };
        nameTextField.setActionCommand("Yo");
        nameTextField.addActionListener(actionListener);
        cityTextField.addActionListener(actionListener);

        KeyListener keyListener = new KeyListener() {
            public void keyPressed(KeyEvent keyEvent) {
                printIt("Pressed", keyEvent);
            }

            public void keyReleased(KeyEvent keyEvent) {
                printIt("Released", keyEvent);
            }

            public void keyTyped(KeyEvent keyEvent) {
                printIt("Typed", keyEvent);
            }

            private void printIt(String title, KeyEvent keyEvent) {
                int keyCode = keyEvent.getKeyCode();
                String keyText = KeyEvent.getKeyText(keyCode);
                System.out.println(title + " : " + keyText + " / " + keyEvent.getKeyChar());
            }
        };
        nameTextField.addKeyListener(keyListener);
        cityTextField.addKeyListener(keyListener);

        InputVerifier verifier = new InputVerifier() {
            public boolean verify(JComponent input) {
                final JTextComponent source = (JTextComponent) input;
                String text = source.getText();
                if ((text.length() != 0) && !(text.equals("Exit"))) {
                    Runnable runnable = new Runnable() {
                        public void run() {
                            JOptionPane.showMessageDialog(source, "Can't leave.", "Error Dialog",
                                    JOptionPane.ERROR_MESSAGE);
                        }
                    };
                    SwingUtilities.invokeLater(runnable);
                    return false;
                } else {
                    return true;
                }
            }
        };
        nameTextField.setInputVerifier(verifier);
        cityTextField.setInputVerifier(verifier);

        DocumentListener documentListener = new DocumentListener() {
            public void changedUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            public void insertUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            public void removeUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            private void printIt(DocumentEvent documentEvent) {
                DocumentEvent.EventType type = documentEvent.getType();
                String typeString = null;
                if (type.equals(DocumentEvent.EventType.CHANGE)) {
                    typeString = "Change";
                } else if (type.equals(DocumentEvent.EventType.INSERT)) {
                    typeString = "Insert";
                } else if (type.equals(DocumentEvent.EventType.REMOVE)) {
                    typeString = "Remove";
                }
                System.out.print("Type  :   " + typeString + " / ");
                Document source = documentEvent.getDocument();
                int length = source.getLength();
                try {
                    System.out.println("Contents: " + source.getText(0, length));
                } catch (BadLocationException badLocationException) {
                    System.out.println("Contents: Unknown");
                }
            }
        };
        nameTextField.getDocument().addDocumentListener(documentListener);
        cityTextField.getDocument().addDocumentListener(documentListener);

        frame.setSize(250, 150);
        frame.setVisible(true);
    }
}