The method addActionListener(ActionListener) in the type AbstractButton is not applicable for the ar

package PopupFrame;

import java.awt.Color;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import javax.swing.ButtonGroup;

import javax.swing.JFrame;

import javax.swing.JPopupMenu;

import javax.swing.JRadioButtonMenuItem;

public class PopupFrame extends JFrame

{

private JRadioButtonMenuItem[] item;

private ButtonGroup buttongroup;

private JPopupMenu popupmenu;

private final Color[] color={Color.BLUE,Color.YELLOW,Color.RED};

public PopupFrame()

{

super("Using JPopupMenus");

ItemHandler handler=new ItemHandler();

String[] colors={"Blue","Yellow","Red"};

item=new JRadioButtonMenuItem[colors.length];

buttongroup=new ButtonGroup();

popupmenu=new JPopupMenu();

for(int count=0;count<item.length;count++)

{

item[count]=new JRadioButtonMenuItem(colors[count]);

popupmenu.add(item[count]);

buttongroup.add(item[count]);

item[count].addActionListener(handler);

}

setBackground(Color.WHITE);

addMouseListener(

new MouseAdapter()

{

public void mousePressed(MouseEvent e)

{

checkForTriggerEvent(e);

}

public void mouseReleased(MouseEvent e)

{

checkForTriggerEvent(e);

}

private void checkForTriggerEvent(MouseEvent e)

{

if(e.isPopupTrigger())

{

popupmenu.show(e.getComponent(),e.getX(), e.getY());

}

}

}

);

}

private class ItemHandler

{

public void actionPerformed(ActionEvent e)

{

for(int i=0;i<item.length;i++)

{

if(e.getSource()==item[i])

{

getContentPane().setBackground(color[i]);

return;

}

}

}

}

}

代码如上，但是那是错误代码，出现这个错误的原因是没有在ItemHandler中实现ActionListener接口，在这个方法后面加上implements ActionListener就可以正常运行了