菜鸟的问题

Question

import java.awt.*;
import java.awt.event.*;public class CloseTest implements WindowListener{
public Frame f; 

public void go(){
f=new Frame("test");
f.setLayout(new FlowLayout());
Button bn=new Button("yy");
f.add(bn);
f.addWindowListener(this);
f.setSize(300,200);
f.setVisible(true);
}

public static void main(String args[]){
CloseTest yy=new CloseTest();
yy.go();
}
public void windowClosed(WindowEvent e) {}
}
CloseTest is not abstract and does not override abstract method windowOpened(java.awt.event.WindowEvent) in java.awt.event.WindowListener
public class CloseTest implements WindowListener{
       ^
1 errorProcess completed.
为什么会这样？

Answer 1

必须实现:windowOpened(WindowEvent e) 方法

Answer 2

由于WindowListener是一个抽象类,所以你需要实现windowOpened(WindowEvent e)方法,可以在你的类里面任意加一个该方法的实现:
public void windowOpened(WindowEvent e){
   //可以啥也不干
}

Answer 3

实现这七方法就行了：         
         public void windowActivated(WindowEvent e){}
public void windowClosed(WindowEvent e){}
public void windowClosing(WindowEvent e){}
public void windowDeactivated(WindowEvent e){}
public void windowDeiconified(WindowEvent e){}
public void windowIconified(WindowEvent e){}
public void windowOpened(WindowEvent e){}
要不然就继承WindowAdapter适配器，这样简单

Answer 4

import java.awt.*;
import java.awt.event.*;public class CloseTest {
public Frame f; 

public void go(){
f=new Frame("test");
f.setLayout(new FlowLayout());
Button bn=new Button("yy");
f.add(bn);
f.addWindowListener(new WindowAdapter(){
                 public void windowClosing(WindowEvent e){
                     System.exit(0);//正常退出
                       }
              }
          );
f.setSize(300,200);
f.setVisible(true);
}
public static void main(String args[]){
CloseTest yy=new CloseTest();
yy.go();
}
}///：~你想这样吧，ok，我给你修改好了。记得要给分哦。
呵呵。