键盘事件问题! 急

Question

还有,怎么判断jtextfield 里的文本 是否是数字?

Answer 1

判断数字你可以getKeyChar(),看其ASCII码是否在0－9之间。
判断backspace你也用getKeyChar()试一试吧。

Answer 2

import java.awt.*;
import java.awt.event.*;
public class TestwindowListener{
public static void main(String args[]){
Frame f = new Frame("Test");
Button btn1 = new Button("press me");
Button btn2 = new Button("press here");
TextArea ta = new TextArea();
Monitor bh = new Monitor();
monitor1 kl = new monitor1();

btn2.setActionCommand("Game over");
ta.addKeyListener(kl);

f.add(btn1,"Center");
f.add(btn2,"North");
f.add(ta,"West");
f.addWindowListener(bh);
f.pack();
f.setVisible(true);
}
}
class monitor1 implements KeyListener{
public void keyTyped(KeyEvent e){
System.out.println(e.KEY_EVENT_MASK);
}
public void keyPressed(KeyEvent e){
System.out.println(e.KEY_EVENT_MASK);
}
public void keyReleased(KeyEvent e){
System.out.println(e.KEY_EVENT_MASK);
}
}
class Monitor implements WindowListener{
public void windowActivated(WindowEvent e){
System.out.println("1");
System.out.println(KeyEvent.VK_BACK_SPACE);

}
public void windowClosed(WindowEvent e){
System.out.println("2");
}
public void windowClosing(WindowEvent e){
System.exit(0);
System.out.println("3");
}
public void windowDeactivated(WindowEvent e){
System.out.println("4");
}
public void windowDeiconified(WindowEvent e){
System.out.println("5");
}
public void windowIconified(WindowEvent e){
System.out.println("6");
}
public void windowOpened(WindowEvent e){
System.out.println("7");
}
}

Answer 3

我要只能敲数字,而且能用 back space 键