testjtextarea.java

java2 primer plus一书源程序

/*
 * TestJTextArea.java
 *
 * Created on July 30, 2002, 2:36 PM
 */

package ch16;

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

/**
 *
 * @author  Stephen Potts
 * @version
 */
public class TestJTextArea extends JFrame implements ActionListener
{
    JButton btnExit;
    JButton btnAppend;
    JButton btnInsert;
    JButton btnReplace;
    JTextArea taLetter;
    JPanel p1;
    JScrollPane sp;
    
    /** Creates new TestJTextArea */
    public TestJTextArea()
    {
        btnAppend = new JButton("Append");
        btnAppend.addActionListener(this);
        btnInsert = new JButton("Insert");
        btnInsert.addActionListener(this);
        btnReplace = new JButton("Replace");
        btnReplace.addActionListener(this);
        btnExit = new JButton("Exit");
        btnExit.addActionListener(this);
        taLetter =
        new JTextArea(10,20);
        taLetter.setLineWrap(true);
        taLetter.setWrapStyleWord(true);
        taLetter.append(
              "I am writing this letter to inform you that you");
        taLetter.append(
              " have been drafted into the United States Army.");
        taLetter.append(
              " You will report to Fort Bragg, North Carolina ");
        taLetter.append(
              "on July 20, 1966.  You will be assigned to ");
        taLetter.append("Vietnam.");
        
        p1 = new JPanel();
        p1.add(taLetter);
        //create the scroll pane
        sp = new JScrollPane(p1);
        sp.setHorizontalScrollBarPolicy(
                   JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        sp.setVerticalScrollBarPolicy(
                   JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        
        getContentPane().add(btnAppend);
        getContentPane().add(btnInsert);
        getContentPane().add(btnReplace);
        getContentPane().add(btnExit);
        getContentPane().add(sp);
        
        this.getContentPane().setLayout(new FlowLayout());
        
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        setTitle("Using a JTextArea Object");
        setBounds( 100, 100, 400, 400);
        setVisible(true);
    }
    
    public void actionPerformed(ActionEvent ae)
    {
        if (ae.getActionCommand().equals("Append"))
            taLetter.append("\n\nSincerely, \n     The Draft Board");
        if (ae.getActionCommand().equals("Insert"))
            taLetter.insert("Dear Steve,\n     ", 0);
        if (ae.getActionCommand().equals("Replace"))
            taLetter.replaceRange("Dear Jerry,\n     ", 0, 12);
        if (ae.getActionCommand().equals("Exit"))
            System.exit(0);
    }
    
    public static void main(String[] args)
    {
        TestJTextArea tjta = new TestJTextArea();
    }
    
}