JAVA打地鼠代码完善

package com.briup.demo.xiangmu;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class PlayMouse {
    private JFrame frame;
    private JPanel northPanel,centerPanel;
    private JComboBox<String> box;
    private JLabel timeLable,timeValue,centLable,centValue;
    private JButton startBtn;
    private JButton[] btns;
    public PlayMouse() {
        JFrame jframe = new JFrame("打地鼠");
        northPanel = new JPanel();
        centerPanel = new JPanel();
        centerPanel.setLayout(new GridLayout(3,3));
        box = new JComboBox<>(new String[] {"初级","中级","高级"});
        timeLable = new JLabel("time:");
        timeValue = new JLabel("10");
        centLable = new JLabel("cent:");
        centValue = new JLabel("0");
        startBtn = new JButton("开始");
        btns = new JButton[9];
        for(int i=0;i<btns.length;i++) {
            btns[i] = new JButton();
            centerPanel.add(btns[i]);
            btns[i].setIcon(new ImageIcon("src/hole.png"));
        }
        northPanel.add(box);
        northPanel.add(timeLable);
        northPanel.add(timeValue);
        northPanel.add(centLable);
        northPanel.add(centValue);
        northPanel.add(startBtn);
        jframe.add(northPanel,BorderLayout.NORTH);
        jframe.add(centerPanel,BorderLayout.CENTER);
        Timer timer = new Timer(1000,new ActionListener() {
            
            private int i;

            @Override
            public void actionPerformed(ActionEvent e) {
                //切换组件的背景图片
                //创建数组存储背景图路径
                String[] images = {"src/mouse.png",};
                //随机产生下标
                Random random = new Random();
                int index = random.nextInt(images.length);
                btns[i].setIcon(new ImageIcon(images[index]));
            }
        });
        //组件添加监听器
        startBtn.addActionListener(new ActionListener() {
                    
            @Override
            public void actionPerformed(ActionEvent e) {
                //用户点击按钮，启动定时器
                timer.start();
                //按钮状态为不可用
                startBtn.setEnabled(false);
            }
        });
        
        jframe.setSize(400,400);
        jframe.setResizable(false);
        jframe.setLocationRelativeTo(null);
        jframe.setVisible(true);
        jframe.setDefaultCloseOperation(3);
    }
    public static void main(String[] args) {
        new PlayMouse();
        
    }

}

这里的数组按钮怎么添加点击事件换成鼠露头的图片？希望有高人能完善代码！

1.PlayMouse类 实现ActionListener接口；
2.38行后面加一行代码
btns[i].addActionListener(this);