import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Demo extends JFrame {
public Demo() {
JLabel l = new JLabel("没有点击键盘Q键");// 创建标签
add(l);// 添加标签
l.addKeyListener(new KeyListener() {// 为标签添加键盘事件监听
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_Q) {// 如果按下的是Q键
l.setText("点击了Q键");// 更改标签的值
}
}
});
setSize(200, 200);// 设置大小
setDefaultCloseOperation(EXIT_ON_CLOSE);// 关闭窗口退出程序
setVisible(true);// 窗体可以显示
}
public static void main(String[] args) {
new Demo();
}
}
这里按Q了,它不显示,怎么办????