清华大学：JAVA教学课件：8-10

程序8-10：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class JTextAreaDemo {
JFrame frame = new JFrame ("JTextArea Demo");
JTextArea ta1,ta2;
JButton copy,clear;
public static void main(String args[]) {
JTextAreaDemo tad = new JTextAreaDemo();
tad.go();
}
public void go() {
ta1 = new JTextArea(3,15);
ta1.setSelectedTextColor(Color.red); //设置选中文本的颜色为红色
ta2 = new JTextArea(7,20);
ta2.setEditable(false); //设置为不可编辑的
//放置到JScrollPane中
JScrollPane jsp1 = new JScrollPane(ta1,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
JScrollPane jsp2 = new JScrollPane(ta2,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
copy = new JButton("Copy");
//将ta1中选中文本或所有内容复制到ta2
copy.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (ta1.getSelectedText()!=null)
ta2.append(ta1.getSelectedText()+"\n");
else
ta2.append("\n"+ta1.getText()+"\n");
}
});
clear = new JButton("Clear");
//将ta2中的内容清空
clear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ta2.setText("");
}
});
JPanel panel1 = new JPanel();
panel1.add(jsp1);
panel1.add(copy);
Border etched = BorderFactory.createEtchedBorder();
panel1.setBorder(etched);
JPanel panel2 = new JPanel();
panel2.add(jsp2);
panel2.add(clear);
panel2.setBorder(etched);
Container cp = frame.getContentPane();
cp.add(panel1,BorderLayout.CENTER);
cp.add(panel2,BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}