我想为两个玩家创建一个简单的蛇游戏。当我开始申请时，首先主窗口欢迎我们。
然后我从菜单栏中选择了玩家数量，并且我预计游戏应该根据玩家的数量来运行。当我点击一个或两个玩家时，调用newgame方法并启动计时器，称为gameTimer。但在Timer中，chargeSnake和disChargeSnake方法无法正常工作。他们没有创建蛇图形并且出现了一些错误。
如果你能提供帮助，我将不胜感激。
感谢。
我的小组：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JPanel;
public class Grafik extends JPanel
{
public Point feed;
public boolean isThereFeed;
private Color feedColor = null;
private Color backgroundColor = null;
private int x_start=0;
private int y_start=0;
private Boolean chargeSnakestate = false;
private Boolean dischargeSnakestate = false;
private Boolean putFeedState = false;
private Color snakeColouuuur = null;
public Grafik(){
System.out.println("inside of grafik const");
feedColor = Color.RED;
feed = new Point();
backgroundColor = Color.PINK;
}
public void createGraphicYard()
{
System.out.println("inside of creategraphicsyard");
setBackground(backgroundColor);
setPreferredSize(new Dimension(400,350));
setBounds(0, 50, 400, 350);
setVisible(true);
}
public void chargeSnake(int x, int y,Color snakeColor)
{
System.out.println("inside of chargesnake");
repaint(x_start,y_start,10,10);
chargeSnakestate =true;
x_start = x;
y_start = y;
snakeColouuuur = snakeColor;
repaint(x_start*10,y_start*10,10,10);
System.out.println("chargeSnake1 : "+ snakeColouuuur+" "+x_start+" "+ y_start );
}
public void dischargeSnake(int x, int y)
{
System.out.println("inside of dischargesnake");
repaint(x_start*10,y_start*10,10,10);
dischargeSnakestate =true;
x_start = x;
y_start = y;
repaint(x_start*10,y_start*10,10,10);
}
public void putFeed(int x,int y)
{
System.out.println("inside of putfeed");
repaint(x_start*10,y_start*10,10,10);
putFeedState =true;
x_start = x;
y_start = y;
repaint(x_start*10,y_start*10,10,10);
}
public boolean isSnakeTookFeed(int snakeX, int snakeY)
{
System.out.println("inside of isSnakeTookFeed");
boolean b=false;
if((feed.x==snakeX)&&(feed.y==snakeY))
b=true;
else
b=false;
return b;
}
public void specifyFeedCoordinate()
{
System.out.println("inside of specifyFeedCoordinate");
List<Integer> possiblePlacesX = new ArrayList<Integer>();
List<Integer> possiblePlacesY = new ArrayList<Integer>();
Dimension size = getSize();
int imageType = BufferedImage.TYPE_INT_ARGB;
BufferedImage image = new BufferedImage(size.width, size.height, imageType);
Graphics2D g2d = image.createGraphics();
paint(g2d);
for(int iy=0;iy<350;iy+=10)
{
for(int ix=0;ix<400;ix+=10)
{
if ((Color.WHITE.equals(new Color(image.getRGB(ix+5, iy+5)))))
{
possiblePlacesX.add(ix / 10);
possiblePlacesY.add(iy / 10);
}
}
}
Random random= new Random();
int rnd=random.nextInt(possiblePlacesX.size()+1);
feed.x=possiblePlacesX.get(rnd);
try {
Thread.sleep(25);
} catch (InterruptedException e) {
e.printStackTrace();
}
feed.y=possiblePlacesY.get(rnd);
}
public Dimension getPreferredSize() {
System.out.println("inside of getpreffered size");
return new Dimension(350,400);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
if(chargeSnakestate)
{
System.out.println("inside of paintComponent");
System.out.println("chargeSnakestate : "+ snakeColouuuur+" "+x_start+" "+ y_start );
g.setColor(snakeColouuuur);
g.fillRect(x_start, y_start, 10, 10);
}
if(dischargeSnakestate)
{
System.out.println("inside of paintComponent");
g.setColor(backgroundColor);
g.fillRect(x_start, y_start, 10, 10);
}
if(putFeedState)
{
System.out.println("inside of paintComponent");
g.setColor(feedColor);
g.fillRect(x_start, y_start, 10, 10);
}
Toolkit.getDefaultToolkit().sync();
g.dispose();
chargeSnakestate=false;
dischargeSnakestate=false;
putFeedState=false;
}
}
我的JFrame：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.concurrent.Semaphore;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Snake_Form extends JFrame {
/**
*
*/
private static final long serialVersionUID = 6139997831592727657L;
private JPanel contentPane;
private Snake []snake;
private Grafik grafik;
int numberOfPlayer=1;
int maxNumberOfPlayer=2;
boolean gameSituation=false;
private JLabel lblFirstPlayerScore;
private JLabel lblSecondPlayerScore;
Color[] clr = {new Color(255,0,0)/*red*/,new Color(0,255,0)/*green*/,new Color(0,0,255)/*blue*/};
private Timer gameTimer;
private Timer waitTimer;
int speed = 1;
public Semaphore semaphore;
public Snake[] getSnake() {
return snake;
}
public void setSnake(Snake[] snake) {
this.snake = snake;
}
/**
* Launch the application.
*/
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
Snake_Form frame = new Snake_Form();
frame.pack();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public Snake_Form() {
setResizable(false);
System.out.println("Snake_FORM");
setPreferredSize(new Dimension(400, 400));
setTitle("SNAKE GAME");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu mnGame = new JMenu("Game");
menuBar.add(mnGame);
JMenuItem start = new JMenuItem("Start");
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("start menu item ına basıldı");
if(!gameSituation)
{
newGame();
}
else
{
gameTimer.setDelay(150);
gameTimer.start();
}
}
});
mnGame.add(start);
JMenuItem stop = new JMenuItem("Stop");
stop.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("stop menu item ına basıldı");
gameTimer.stop();
}
});
mnGame.add(stop);
JMenuItem newGame = new JMenuItem("New Game");
newGame.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("new game menu item ına basıldı");
newGame();
}
});
mnGame.add(newGame);
JMenu mnSpeed = new JMenu("Speed");
menuBar.add(mnSpeed);
JMenuItem level1 = new JMenuItem("Level 1");
level1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 1 menu item ına basıldı");
speed = 1;
gameTimer.setDelay(150);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level1);
JMenuItem level2 = new JMenuItem("Level 2");
level2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 2 menu item ına basıldı");
speed = 2;
gameTimer.setDelay(130);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level2);
JMenuItem level3 = new JMenuItem("Level 3");
level3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("LEvel 3 menu item ına basıldı");
speed = 3;
gameTimer.setDelay(110);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level3);
JMenuItem level4 = new JMenuItem("Level 4");
level4.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("level 4 menu item ına basıldı");
speed = 4;
gameTimer.setDelay(90);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level4);
JMenuItem level5 = new JMenuItem("Level 5");
level5.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("level 5 menu item ına basıldı");
speed = 5;
gameTimer.setDelay(80);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level5);
JMenuItem level6 = new JMenuItem("Level 6");
level6.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 6 menu item ına basıldı");
speed = 6;
gameTimer.setDelay(70);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level6);
JMenuItem level7 = new JMenuItem("Level 7");
level7.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 7 menu item ına basıldı");
speed = 7;
gameTimer.setDelay(60);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level7);
JMenuItem level8 = new JMenuItem("Level 8");
level8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 8 menu item ına basıldı");
speed = 8;
gameTimer.setDelay(50);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level8);
JMenuItem level9 = new JMenuItem("Level 9");
level9.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Level 9 menu item ına basıldı");
speed = 9;
gameTimer.setDelay(40);
for (int i = 0; i < numberOfPlayer; i++)
{
snake[i].snakeSpeed=speed;
}
}
});
mnSpeed.add(level9);
JMenu mnPlayer = new JMenu("Player");
menuBar.add(mnPlayer);
JMenuItem mntmOnePlayer = new JMenuItem("One Player");
mntmOnePlayer.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("One Player menu item ına basıldı");
numberOfPlayer = 1;
lblFirstPlayerScore.setVisible(true);
lblSecondPlayerScore.setVisible(false);
lblFirstPlayerScore.setText("Birinci Oyuncu PUAN : " + snake[0].score );
newGame();
}
});
mnPlayer.add(mntmOnePlayer);
JMenuItem mntmTwoPlayer = new JMenuItem("Two Player");
mntmTwoPlayer.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Two Player menu item ına basıldı");
numberOfPlayer = 2;
lblFirstPlayerScore.setVisible(true);
lblSecondPlayerScore.setVisible(true);
lblFirstPlayerScore.setText("Birinci Oyuncu PUAN : " + snake[0].score );
lblSecondPlayerScore.setText("ikinci Oyuncu PUAN : " + snake[1].score );
newGame();
}
});
mnPlayer.add(mntmTwoPlayer);
JMenu mnHelp = new JMenu("Help");
menuBar.add(mnHelp);
final JMenuItem learnGame = new JMenuItem("Learn Game");
learnGame.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
JOptionPane.showMessageDialog(learnGame, " Game starts when the user select the “Player” menu \nfrom the game board and choose how many people\nhe/she will want to play.\n\n Joy pad will be appointed for the -One Player- \nand E,S,F,D will be appointed for the -Second Player- \nto play the game. (E->Up S->Left F->Right D->Down).","Learn Game",JOptionPane.INFORMATION_MESSAGE);
}
});
mnHelp.add(learnGame);
final JMenuItem aboutGame = new JMenuItem("About Game");
aboutGame.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(aboutGame, "Snake Game written by Merve =)", "About Game", JOptionPane.INFORMATION_MESSAGE);
}
});
mnHelp.add(aboutGame);
contentPane = new JPanel();
// contentPane.setSize(new Dimension(400, 400));
contentPane.setBounds(0,0,400,400);
contentPane.setPreferredSize(new Dimension(400,400));
contentPane.setBackground(Color.WHITE);
setContentPane(contentPane);
contentPane.setLayout(null);
lblFirstPlayerScore = new JLabel("lblFirstPlayerScore");
lblFirstPlayerScore.setBounds(10, 0, 150, 25);
lblFirstPlayerScore.setVisible(false); //when the game is loaded score does not seem
contentPane.add(lblFirstPlayerScore);
lblSecondPlayerScore = new JLabel("lblSecondPlayerScore");
lblSecondPlayerScore.setBounds(10, 25, 150, 25);
lblSecondPlayerScore.setVisible(false); //when the game is loaded score does not seem
contentPane.add(lblSecondPlayerScore);
grafik= new Grafik();
grafik.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode()==KeyEvent.VK_LEFT) snake[1].route=1;
if(e.getKeyCode()==KeyEvent.VK_RIGHT) snake[1].route=2;
if(e.getKeyCode()==KeyEvent.VK_UP) snake[1].route=3;
if(e.getKeyCode()==KeyEvent.VK_DOWN) snake[1].route=4;
//if (e.KeyCode == Keys.Escape) Application.Exit();
if(e.getKeyCode()==KeyEvent.VK_S) snake[1].route=1;
if(e.getKeyCode()==KeyEvent.VK_F) snake[1].route=2;
if(e.getKeyCode()==KeyEvent.VK_E) snake[1].route=3;
if(e.getKeyCode()==KeyEvent.VK_D) snake[1].route=4;
for(int i=0;i<numberOfPlayer;i++)
{
snake[i].waitInt=20;
}
waitTimer.stop();
gameTimer.start();
}
});
grafik.createGraphicYard();
grafik.feed.x=-1;
grafik.feed.y=-1;
grafik.isThereFeed=false;
contentPane.add(grafik);
//when the game is loaded 2 Snake Object is set
snake= new Snake[maxNumberOfPlayer];
//start the game with one player
for(int i=0; i<maxNumberOfPlayer;i++)
{
snake[i]= new Snake();
}
//Create a timer.
gameTimer = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
gameTickerTick();
}
});
//Create a timer.
waitTimer = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
waitTimerTick();
}
});
semaphore= new Semaphore(1);
}
void newGame()
{
System.out.println("new Game icindeyim");
gameTimer.stop();
grafik.createGraphicYard();
grafik.isThereFeed=false;
for(int i=0; i<numberOfPlayer;i++)
{
snake[i].length=5;
snake[i].tailLength=5;
snake[i].x=5+i*5;
snake[i].y=5+i*5;
snake[i].route=2-i;
snake[i].score=0;
snake[i].defaultSnake();
snake[i].snakeColor = clr[i];
}
gameSituation=true;
gameTimer.start();
}
private void snakeGameIsOver() {
System.out.println("oyun bitti");
gameSituation=false;
try {
gameTimer.wait(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(!gameSituation)
gameTimer.stop();
else
gameTimer.start();
if(numberOfPlayer==1)
JOptionPane.showMessageDialog(lblFirstPlayerScore, "Game is over...");
else
JOptionPane.showInputDialog(lblFirstPlayerScore+"\n"+lblSecondPlayerScore, "Game is over..");
lblFirstPlayerScore.setText("SCORE: "+snake[0].score);
grafik.createGraphicYard();
grafik.isThereFeed=gameSituation;
if(!gameSituation)
gameTimer.stop();
else
gameTimer.start();
}
void gameTickerTick()
{
System.out.println(" In gametimer");
try {
semaphore.acquire();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
for(int i=0;i<numberOfPlayer;i++)
{
//shift the snake one unit to its route
if(snake[i].route==1) snake[i].snakeGoesLeft();
if(snake[i].route==2) snake[i].snakeGoesRight();
if(snake[i].route==3) snake[i].snakeGoesUp();
if(snake[i].route==4) snake[i].snakeGoesDown();
//when the game area border ends permits the snake pass other side
if(snake[i].x>39) snake[i].x=0;
else if(snake[i].x<0) snake[i].x=40;
if(snake[i].y>39) snake[i].y=0;
else if(snake[i].y<0) snake[i].y=40;
System.out.println("I will charge");
//charge the snake
grafik.chargeSnake(snake[i].x,snake[i].y,snake[i].snakeColor);
System.out.println("I have charged");
//adds the added unit to tail of snake
snake[i].areaX[snake[i].tailLength]=snake[i].x;
snake[i].areaY[snake[i].tailLength]=snake[i].y;
snake[i].tailLength++;
System.out.println("I will discharged");
//discharge the snake
grafik.dischargeSnake(snake[i].areaX[snake[i].tailLength-snake[i].length], snake[i].areaY[snake[i].tailLength-snake[i].length]);
System.out.println("I have discharged");
if(snake[i].tailLength>899)
{
snake[i].tailLength=snake[i].length;
for(int z=0;z<snake[i].length;++z)
{
snake[i].areaX[snake[i].length-z]=snake[i].areaX[900-z];
snake[i].areaY[snake[i].length-z]=snake[i].areaY[900-z];
}
}
if((grafik.isSnakeTookFeed(snake[i].x, snake[i].y)==false)&&(grafik.isThereFeed==false))
{
//create new feed and its coordinate
grafik.specifyFeedCoordinate();
grafik.putFeed(grafik.feed.x,grafik.feed.y);
grafik.isThereFeed=true;
}
if(grafik.isSnakeTookFeed(snake[i].x, snake[i].y)==true)
{
grafik.feed.x=-1;
grafik.feed.y=-1;
grafik.isThereFeed=false;
snake[i].score+=1*snake[i].snakeSpeed;
snake[i].length+=1;
if(i==0)
lblFirstPlayerScore.setText("First Player Score: "+snake[i].score);
else if(i==1)
lblSecondPlayerScore.setText("Second Player Score: "+snake[i].score);
}
}
for(int i=0;i<numberOfPlayer;i++)
{
if(snake[i].isSnakeCrashedItself(contentPane)==true)
{
gameTimer.stop();;
waitTimer.start();
if(snake[i].waitInt<=0)
{
}
else
{
snake[i].waitInt=20;
}
}
}
semaphore.release();
}
void waitTimerTick()
{
System.out.println("wait timer");
for(int i=0;i<numberOfPlayer;i++)
{
snake[i].waitInt--;
if(snake[i].waitInt==0)
{
waitTimer.stop();
snakeGameIsOver();
break;
}
}
}
}
我的蛇对象：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JPanel;
public class Snake
{
public Color snakeColor;
public int route;
public int length,tailLength;
public int x,y,snakeSpeed;
public int score;
public int waitInt;
public int[] areaX= new int[1000];
public int[] areaY= new int[1000];
protected Random randomm;
//Snake constructor
public Snake()
{
snakeColor= Color.BLUE;
snakeSpeed=1;
randomm= new Random();
System.out.println("Snake has been constructed.");
}
//turn the snake right side
public void snakeGoesRight()
{
this.x+=1;
}
//turn the snake left side
public void snakeGoesLeft()
{
this.x-=1;
}
//turn the snake upper
public void snakeGoesUp()
{
this.y-=1;
}
//turn the snake down side
public void snakeGoesDown()
{
this.y+=1;
}
//check the snake if it s crashed itself or not
public boolean isSnakeCrashedItself(JPanel jpanel)
{
System.out.println("inside of isSnakeCrashedItself function");
Dimension size = jpanel.getSize();
int imageType = BufferedImage.TYPE_INT_ARGB;
BufferedImage image = new BufferedImage(size.width, size.height, imageType);
Graphics2D g2d = image.createGraphics();
jpanel.paint(g2d);
boolean situation= false;
int x= this.x*10;
int y=this.y*10;
try
{
if(route==1)
{
if((!Color.WHITE.equals(new Color(image.getRGB(x-5,y+5)))))
{
situation=true;
}
else
situation=false;
}
if(route==2)
{
if((!Color.WHITE.equals(new Color(image.getRGB(x+15, y+5)))))
{
situation=true;
}
else
situation=false;
}
if(route==3)
{
if((!Color.WHITE.equals(new Color(image.getRGB(x+5, y-5)))))
{
situation=true;
}
else
situation=false;
}
if(route==4)
{
if((!Color.WHITE.equals(new Color(image.getRGB(x+5, y+15)))))
{
situation=true;
}
else
situation=false;
}
}
catch(Exception e)
{
//e.message
return false;
}
return situation;
}
//it makes the snake s properties default
public void defaultSnake()
{
System.out.println("inside of default snake function");
areaX=null;
areaY=null;
areaX= new int[1000];
areaY=new int[1000];
for(int i=0;i<1000;i++)
{
areaX[i]=0;
areaY[i]=0;
}
}
}
控制台输出：
I will charge
inside of chargesnake
chargeSnake1 : java.awt.Color[r=255,g=0,b=0] 6 5
I have charged
I will discharged
inside of dischargesnake
I have discharged
inside of isSnakeTookFeed
inside of specifyFeedCoordinate
inside of paintComponent
chargeSnakestate : java.awt.Color[r=255,g=0,b=0] 0 0
inside of paintComponent
Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at Grafik.specifyFeedCoordinate(Grafik.java:117)
at Snake_Form.gameTickerTick(Snake_Form.java:498)
at Snake_Form$19.actionPerformed(Snake_Form.java:378)
at javax.swing.Timer.fireActionPerformed(Unknown Source)
at javax.swing.Timer$DoPostEvent.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
答案 0 :(得分：2)
int rnd=random.nextInt(possiblePlacesX.size()+1);
feed.x=possiblePlacesX.get(rnd);
// ...
feed.y=possiblePlacesY.get(rnd);
看看你在这做什么？您最终可能会得到rnd的值与列表的大小相同，这当然会为您提供上面的好堆栈跟踪。
在您的确切情况下，您的列表为空（size() == 0），并且您正在尝试访问项0。相反，你应该只处理这种情况（空列表）和（可能）什么都不做。
你的代码中还有其他问题，比如@MadProgrammer提到的问题，我不会详细介绍......