JTextArea 限制用户输入问题！（急！急！急！）

[hccpro]

怎样限制用户输入不能超出JTextArea可视大小？（主要指不能超出纵向范围）

已设LineWrap为true，则到行末自动换行，可自动换行并没插入回车符，无法测定回车

数。而且如用户粘贴大量文本到JTextArea，则用keyPressed也无法监控！


（很急，请求帮助！俺给分！）

[Habib]

我也想知道

[v不吃v你]

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

public class NoEditArea extends JTextArea {

public NoEditArea(String string,int rows,int columns){

super(string,rows,columns);
addKeyListener(new KeyAdapter(){

public void keyTyped(KeyEvent key) {
key.consume();
}

public void keyPressed(KeyEvent key) {

JTextArea temp = (JTextArea)key.getSource();
int caretPos = temp.getCaretPosition();
switch(key.getKeyCode()) {
case(KeyEvent.VK_LEFT):
case(KeyEvent.VK_BACK_SPACE) : if(caretPos > 0) { temp.setCaretPosition(caretPos - 1); } break;
case(KeyEvent.VK_RIGHT) : if(caretPos < temp.getText().length()) { temp.setCaretPosition(caretPos + 1); } break;
case(KeyEvent.VK_DELETE):System.out.println("aaa");break;
default : break;
}
key.consume();
}

public void keyReleased(KeyEvent key) {
key.consume();
}
});
}

public static void main(String[] args) {
JFrame frame = new JFrame("Non-Delete");
JButton pastebutton = new JButton("Paste");
JPanel panel = new JPanel();
final NoEditArea area = new NoEditArea("can't delete",30,50);
JScrollPane srollPane = new JScrollPane(area); //改进的地方



pastebutton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Clipboard cb = Toolkit.getDefaultToolkit().getSystemClipboard();
Transferable content = cb.getContents(this);
try {
String s = (String)content.getTransferData(DataFlavor.stringFlavor);
area.setText(s);
}
catch (Throwable exc) {
System.err.println(e);
}
}
});

panel.add(pastebutton,BorderLayout.NORTH);
panel.add(srollPane,BorderLayout.CENTER);
frame.getContentPane().add(panel);
frame.setSize(250,100);
frame.setVisible(true);
frame. addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
});

}
}