testtextlistener.java

java2 primer plus一书源程序

/*
 * TestTextListener.java
 *
 * Created on August 9, 2002, 2:32 PM
 */

package ch14;

import java.awt.*;
import java.awt.event.*;


/**
 *
 * @author  Stephen Potts
 */
public class TestTextListener extends Frame implements TextListener
{
    TextField tField;
    TextField tField2;
    
    
    /** Creates a new instance of TestTextListener */
    public TestTextListener()
    {
        tField = new TextField(20);
        tField2 = new TextField(20);
        tField.addTextListener(this);
        add(tField);
        add(tField2);
        
        
        
        this.setLayout(new FlowLayout());
        
        addWindowListener(new WinCloser());
        setTitle("Using a TextListener Object");
        setBounds( 100, 100, 400, 400);
        setVisible(true);
    }
    
    
    public static void main(String[] args)
    {
        TestTextListener ttl= new TestTextListener();
    }
    
    public void textValueChanged(java.awt.event.TextEvent te)
    {
        TextField tf = (TextField)te.getSource();
        String s1 = tf.getText();
        int strlen = s1.length();
        String lastCharString = s1.substring(strlen-1);
        try
        {
            int i = Integer.parseInt(lastCharString);
            tField2.setText(tField2.getText() + lastCharString);
        }catch (NumberFormatException nfe)
        {
            System.out.println("not a number");
        }
        
    }
    
}

class WinCloser extends WindowAdapter
{
    public void windowClosing(WindowEvent e)
    {
        System.exit(0);
    }
}