GUI给多个按钮设置事件监听器的问题

[weiyuqi723]

这个程序会显示几张图片，然后让USER判断图片的数量。第一次会出现10张图片，判断正确后则会随机出现图片。
我给多个有图片的按钮设置事件监听器，使USER点击某个按钮时，该按钮消失。
有两个问题：
1.第一次显示10张图片时，点击图片按钮，为什么会显示数组下标越界？
2.第一次输入正确后，之后的随机显示图片，再点击图片，为什么图片不会消失？

import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener;
import java.awt.Image;
import javax.imageio.ImageIO;
import java.io.*;

public class JungleParty{
	//Declaration of the wedgets of the GUI.
	JFrame JP = new JFrame();
	JLabel ques = new JLabel("How many animals have come to the party?");
	JButton[] pic = new JButton[10];
	JLabel instruction = new JLabel("Click on animals you wish to kick out of the party!");
	ImageIcon[] array = new ImageIcon[10];
	JPanel Animals = new JPanel();
	JPanel Ins = new JPanel();
	JPanel Q = new JPanel();
	
	JComboBox Selector;
	int i = 10, l = 0;
	
	/** This is the initialisation of the wedgets*/
	public void Init(){
		//Read the images
		readImage();
		
		//Set the attibutes of the JFrame
		JP.setLayout(new BorderLayout());
		JP.setTitle("Welcome to the Jungle Party!");
		JP.setSize(600,400);
		
		Animals.setLayout(new GridLayout(0, 5));
		setIcon(i);
		Q.setLayout(new FlowLayout(FlowLayout.CENTER));
		instruction.setForeground(Color.red);
		
		//Set the EventListener
		Vector<String> choice = new Vector<String>();
		choice.add("0");
		choice.add("1");
		choice.add("2");
		choice.add("3");
		choice.add("4");
		choice.add("5");
		choice.add("6");
		choice.add("7");
		choice.add("8");
		choice.add("9");
		choice.add("10");
		Selector = new JComboBox(choice);
		Selector.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent e){
				Object o = Selector.getSelectedItem();
				int ans = Integer.parseInt(String.valueOf(o));
				if(ans == i){
					int rand = (int)(Math.random()*9+1);
					ques.setText("Correct! How many animals are in the party now?");
					Animals.removeAll();
					Animals.updateUI();
					setIcon(rand);
					i = rand;
				}

				else if(ans != i){
					ques.setText("Wrong!Try again!");
				}
				
			}
		});
		
		//Add other wedgets to the main JFrame
		Q.add(ques);
		Q.add(Selector);
		Ins.add(instruction);
		JP.add(BorderLayout.NORTH, Animals);
		JP.add(BorderLayout.CENTER, Q);
		JP.add(BorderLayout.SOUTH, Ins);
		JP.setVisible(true);
		JP.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		JP.pack();
	}
	
	/** This is the method to read the images*/
	public void readImage(){
		for(int j=0; j<10; j++){
			switch(j){
				case 0:  array[j] = new ImageIcon("animal1.png"); break;
				case 1:  array[j] = new ImageIcon("animal2.png"); break;
				case 2:  array[j] = new ImageIcon("animal3.png"); break;
				case 3:  array[j] = new ImageIcon("animal4.png"); break;
				case 4:  array[j] = new ImageIcon("animal5.png"); break;
				case 5:  array[j] = new ImageIcon("animal6.png"); break;
				case 6:  array[j] = new ImageIcon("animal7.png"); break;
				case 7:  array[j] = new ImageIcon("animal8.png"); break; 
				case 8:  array[j] = new ImageIcon("animal9.png"); break;
				case 9:  array[j] = new ImageIcon("animal10.png"); break;
			}
		}
	}
	
	/** This is the method to add the images to the Animals JPanel
	 *  @param k The number of images that should be displayed.
	 */
	public void setIcon(int k){
		for(l = 0; l<k; l++){
			pic[l]= new JButton(array[l]);
			Animals.add(pic[l]);
			pic[l].addActionListener(new ActionListener(){
				public void actionPerformed(ActionEvent e){
					pic[l].setVisible(false);
					Animals.updateUI();
					if(i != 0) i--;
					else i = 0;
					instruction.setText("Animal gone! How many animals are in the party now?");
				}
			});
		}
	}
	
	/** The main function*/
	public static void main(String[] args){
		JungleParty J = new JungleParty();
		J.Init();
	}
}