实现接口出错

Question

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Example25_1 implements WindowListener//为什么这个实现windowlistenr接口会出错呢
{
public static void main(String args[])
{
JButton button=new JButton("轻组件按钮");
JTextArea text=new JTextArea("轻组件",20,20);
JFrame jframe=new JFrame("根窗体");
jframe.setSize(200,300);
jframe.setBackground(Color.blue);
jframe.setVisible(true);
jframe.pack();
jframe.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
Container contentpane=jframe.getContentPane();
contentpane.add(button,BorderLayout.SOUTH);
contentpane.add(text,BorderLayout.CENTER);
jframe.pack();
}
}

Answer 1

没实现他的下面的方法
/* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowOpened(java.awt.event.WindowEvent)
 */
public void windowOpened(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowClosing(java.awt.event.WindowEvent)
 */
public void windowClosing(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowClosed(java.awt.event.WindowEvent)
 */
public void windowClosed(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowIconified(java.awt.event.WindowEvent)
 */
public void windowIconified(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowDeiconified(java.awt.event.WindowEvent)
 */
public void windowDeiconified(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowActivated(java.awt.event.WindowEvent)
 */
public void windowActivated(WindowEvent arg0) {
// TODO Auto-generated method stub

} /* (non-Javadoc)
 * @see java.awt.event.WindowListener#windowDeactivated(java.awt.event.WindowEvent)
 */
public void windowDeactivated(WindowEvent arg0) {
// TODO Auto-generated method stub

}

Answer 2

用WindowAdapter
可以不用实现

Answer 3

Example25_1 不是抽象的，并且未覆盖 java.awt.event.WindowListener 中的抽象方法 windowDeactivated(java.awt.event.WindowEvent)