我使用java和swing编写了一个贪吃蛇的程序，可以顺利运行，但有两个小问题，一直不知道如何解决。第一个是当蛇吃到随机出来的点时，蛇的长度会加1，但蛇身后面会出来一个
新的点，随着蛇移动蛇身的距离而消失；第二个问题是有时候运行游戏会不能控制，希望大神费心解答一下。

package game;

import java.awt.Color;

public class SnakeNode {//定义蛇身集合中的各个元素点
    private int x;
    private int y;
    private Color color;
    public SnakeNode() {
        super();
        // TODO Auto-generated constructor stub
    }
    public SnakeNode(int x, int y, Color color) {
        super();
        this.x = x;
        this.y = y;
        this.color = color;
    }
    public int getX() {
        return x;
    }
    public void setX(int x) {
        this.x = x;
    }
    public int getY() {
        return y;
    }
    public void setY(int y) {
        this.y = y;
    }
    public Color getColor() {
        return color;
    }
    public void setColor(Color color) {
        this.color = color;
    }



}

 package game;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Random;

import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.Timer;

public class MainGame extends JPanel{
    private final int length = 20;//定义画板的长
    private final int width = 30;//定义画板的宽
    private final int unit = 20;//定义单位长度
    private ArrayList<SnakeNode> snake = new ArrayList<>();//定义蛇身的集合
    private int Direction;//定义蛇头的方向
    private int Length ;//定义蛇身的长度
    private SnakeNode newNode = new SnakeNode(1,1,Color.BLACK);//定义随机点
    Timer time = new Timer(100,new ThingsListener());

    public int getDirection() {
        return Direction;
    }

    public void setDirection(int direction) {
        Direction = direction;
    }

    public int getLength() {
        return Length;
    }

    public void setLength(int length) {
        Length = length;
    }

    public SnakeNode getNewNode() {
        return newNode;
    }

    public void setNewNode(SnakeNode newNode) {
        this.newNode = newNode;
    }

    public MainGame() {//初始化各项数据与方法
        snake.add(new SnakeNode(width/2,length/2,Color.GREEN));
        snake.add(new SnakeNode(width/2,length/2,Color.BLUE));
        snake.add(new SnakeNode(width/2,length/2,Color.RED));

        Direction = 1;//定义初始方向为向上
        Length = 3;//蛇身长度为3
        CreateNode();//产生随机点

        this.addKeyListener(new KeyAdapter() {//捕捉键盘的按键事件
            public void keyPressed(KeyEvent e) {
                int direction = 0;//定义一个按下按钮后要去的方向
                switch(e.getKeyCode()) {
                    case KeyEvent.VK_UP://按下向上，返回1
                        direction = 1;
                        break;
                    case KeyEvent.VK_DOWN://按下向下，返回-1
                        direction = -1;
                        break;
                    case KeyEvent.VK_LEFT://按下相左，返回2
                        direction = 2;
                        break;
                    case KeyEvent.VK_RIGHT://按下向右，返回-2
                        direction = -2;
                        break;
                    default:
                        break;
                }
                if(direction + Direction !=0) {//不能反向运动
                    Direction = direction;
                    Move(direction);
                    repaint();
                }
            }
        });
        time.start();

    }
    public void Move(int direction) {//定义蛇身移动的方法
        int FirstX = snake.get(0).getX();//获取蛇第一个点
        int FirstY = snake.get(0).getY();//获取蛇第二个点

        switch(direction) {
            case 1:
                FirstY--;
                break;
            case -1:
                FirstY++;
                break;
            case 2:
                FirstX--;
                break;
            case -2:
                FirstX++;
                break;
            default:
                break;
        }

        if(FirstX == newNode.getX()&&FirstY == newNode.getY()) {//当碰到随机点时
            getNode();
            repaint();
        }

        for(int x = 0; x < Length; x++) {//当碰到蛇身自己时
            if((FirstX==snake.get(x).getX())&&(FirstY == snake.get(x).getY())) {
                Dead("你碰到自己啦~~~");
            }
        }

        if(FirstX < 0 || FirstX > width -1 || FirstY < 0 || FirstY > length -1) {
            Dead("菜鸡，你撞墙啦~~~~~");
        }



        for(int x = Length - 1; x > 0; x--) {
            snake.get(x).setX(snake.get(x-1).getX());
            snake.get(x).setY(snake.get(x-1).getY());
        }
        snake.get(0).setX(FirstX);
        snake.get(0).setY(FirstY);
        repaint();
    }

    public void getNode() {
        SnakeNode addNode = new SnakeNode(newNode.getX(),newNode.getY(),newNode.getColor());
        snake.add(addNode);
        Length++;
        for(int x = Length-1; x >0; x--) {
            snake.get(x).setX(snake.get(x-1).getX());
            snake.get(x).setY(snake.get(x-1).getY());
            snake.get(x).setColor(snake.get(x-1).getColor());
        }
        snake.get(0).setX(addNode.getX());
        snake.get(0).setY(addNode.getY());
        snake.get(0).setColor(addNode.getColor());
        CreateNode();
        repaint();


    }

    public void Dead(String s) {
        Date date = new Date();
        SimpleDateFormat sd = new SimpleDateFormat();
        String str2 = sd.format(date);
        String str = s +"\n" +"所以说游戏不得已将结束了";
        JOptionPane.showMessageDialog(this, str2 + "\n" + str   );
        System.exit(0);
    }

    public void CreateNode() {//创造随机点的方法
        int newX = 0;
        int newY = 0;
        Boolean flag = true;
        while(flag) {
        newX = new Random().nextInt(width);
        newY = new Random().nextInt(length);

        for(int i = 0; i < Length; i++) {
            if(snake.get(i).getX()==newX && snake.get(i).getY()==newY) {
                flag = true;
                break;
            }
                flag= false;
            }
        }

        Color color = new Color(new Random().nextInt(255),new Random().nextInt(255),new Random().nextInt(255));
        newNode.setX(newX);
        newNode.setY(newY);
        newNode.setColor(color);
        snake.get(0).setColor(newNode.getColor());

    }

    class ThingsListener implements ActionListener {//设置一个监听器事件
        public void actionPerformed(ActionEvent e) {
            Move(Direction);
            repaint();
        }
    }

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(newNode.getColor());
        g.fillOval(newNode.getX()*unit, newNode.getY()*unit, unit, unit);
        g.setColor(newNode.getColor());
        g.drawRect(0, 0, width*unit, length*unit);
        for(int x = 0; x < Length; x++) {
            g.setColor(snake.get(x).getColor());
            g.fillOval(snake.get(x).getX()*unit, snake.get(x).getY()*unit, unit, unit);
        }

    }




}

 package game;

import java.awt.Color;

import javax.swing.JFrame;

public class Test {
    public static void main(String[] args) {
        JFrame frame = new JFrame("贪吃蛇————————————made by chenjiaheng");
        frame.setBackground(Color.white);
        frame.setBounds(0,0,800,500);
        MainGame sn = new MainGame();
        frame.add(sn);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        sn.requestFocus();
    }

}

while(y--)是什么意思 求大神解答 谢谢

Frost_Jiang

7个回复

while(y--)是什么意思求大神解答谢谢