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在设计该游戏时，首先是做出一个主界面 即 SnakeUI 类，在该类中要对主界面的润饰，蛇的初始化，食物的初始化，键盘的监听事件，
1，SnakeUI 类
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class SnakeUI extends JFrame implements KeyListener {
private BufferedImage uiImg = new BufferedImage(Constant.JFRAME_WIDTH,
Constant.JFRAME_HEIGHT, BufferedImage.TYPE_3BYTE_BGR);
private Rectangle rec;
private SNode food;
private Snake snake; // 定义蛇对象
private static int SPEED = Constant.SNAKE_NORMAL;
public SnakeUI() {
this.rec = Constant.rec;
this.food = new SNode(Color.BLUE);
this.snake = new Snake(this);// 初始化蛇对象
this.launchFrame();
}
// 取得以后界面的食物
public SNode getFood() {
return food;
}
private void launchFrame() {
this.setTitle(“ 贪吃蛇 V0.1”);
this.setBounds(200, 100, Constant.JFRAME_WIDTH, Constant.JFRAME_HEIGHT);
this.setVisible(true);
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
new Thread(new UIUpdate()).start(); // 启动更新线程
this.addKeyListener(this); // 监听键盘事件
}
public void paint(Graphics g) {
// 1. 间接画入图形。g.drawRect 画入闪动成果 [不可取]
// 2. 将图形画入到缓存图片，再讲图片画入到 Frame 中，防止闪动成果
// 设置矩形的色彩，并绘入到 uiImg 图片，将此图片间接写入到内存
Graphics2D g2d = (Graphics2D) uiImg.getGraphics();
// 在缓存图片画红色背景
g2d.setColor(Color.WHITE);
g2d.fillRect(0, 0, this.getWidth(), this.getHeight());
// 设置边框色彩
g2d.setColor(Color.BLACK);
g2d.drawRect((int) this.rec.getX(), (int) this.rec.getY(),
(int) this.rec.getWidth(), (int) this.rec.getHeight());
// 设置两头方格
g2d.setColor(Color.CYAN);
int startx = (int) this.rec.getX();
int starty = (int) this.rec.getY();
for (int i = 0; i < 35; i++) {
for (int j = 0; j < 50; j++) {
g2d.drawRect(startx + j * Constant.FOOD_WIDTH, starty + i
* Constant.FOOD_HEIGHT, Constant.FOOD_WIDTH,
Constant.FOOD_HEIGHT);
}
}
// 设置版本文字
g2d.setColor(Color.RED);
g2d.setFont(new Font(“ 宋体 ”, Font.ITALIC, 16));// 设置字体
g2d.drawString(“ 版本文字 2019”, 580, 530);
// 画食物, 食物 paint 办法在 SNode 类定义，在 UI 界面中的 paint 办法被调用
this.food.paint(g2d);
// 画蛇
this.snake.paint(g2d);
// 蛇吃食物绘制: 蛇曾经在吃食物, 食物被吃完后从新定义一个食物对象，并与蛇的身材做重叠判断
if (this.snake.eat(this.food)) {
this.food = new SNode(Color.BLUE);
while (this.snake.hit(this.food)) {
this.food = new SNode(Color.BLUE);
}
}
g.drawImage(uiImg, 0, 0, null); // 写入到内存
}
public static void main(String[] args) {
new SnakeUI();
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
// 按压键盘次要目标更改蛇静止方向
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
switch (key) {
case KeyEvent.VK_LEFT:
snake.setDir(Constant.L);
System.out.println(“dddl”);
break;
case KeyEvent.VK_RIGHT:
snake.setDir(Constant.R);
System.out.println(“dddr”);
break;
case KeyEvent.VK_UP:
snake.setDir(Constant.U);
System.out.println(“dddu”);
break;
case KeyEvent.VK_DOWN:
snake.setDir(Constant.D);
break;
case KeyEvent.VK_W:
SPEED = Constant.SNAKE_ADD;
break;
case KeyEvent.VK_D:
SPEED = Constant.SNAKE_NORMAL;
break;
case KeyEvent.VK_S:
SPEED = Constant.SNAKE_SUB;
break;
case KeyEvent.VK_T:
SPEED = Constant.SNAKE_SUPER;
break;
}
}
@Override
public void keyReleased(KeyEvent e) {
SPEED = Constant.SNAKE_NORMAL;
}
// 一直刷新界面的线程
class UIUpdate implements Runnable {
@Override
public void run() {
while (SnakeUI.this.snake.isLive()) {
System.out.println(“…………..thread….”);
SnakeUI.this.repaint();
// 为了减缓更新的速度，设定每一次绘制之后进展 1 秒。
外汇常见问题 https://www.fx61.com/faq
try {
Thread.sleep(SPEED);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
JOptionPane.showMessageDialog(SnakeUI.this, “ 游戏越界，game over.”);
}
}
}
2，Snake 蛇类
实例化蛇这个类，应用的是一个 list 汇合对蛇的各个局部进行存储以及显示，
import java.awt.Color;
import java.awt.Graphics2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JOptionPane;
public class Snake {
private SNode snakeHead; // 蛇头结点
private int startx, starty; // 蛇头的坐标
private List nodes = new ArrayList(); // 整条蛇，由 SNode 结点组成:
// 线性表 List
private int dir; // 方位
private boolean isLive = true; // 蛇处于运行状态
// 给蛇增加运行速度, 每一次运行走 3 个像素
private int speed = 3;
// getter.setter 蛇的方向
public int getDir() {
return dir;
}
public void setDir(int dir) {
this.dir = dir;
}
// 传入蛇所在的界面，通过界面取得以后的食物对象
public Snake(SnakeUI ui) {
this.dir = Constant.U;
this.noOverride(ui.getFood());
}
// 随机产生蛇头的坐标与食物不反复
public void noOverride(SNode food) {
this.generateSnake();
while (this.hit(food)) {// 蛇与食物重叠
this.generateSnake();
}
}
private void generateSnake() {
int x = SNode.generate(50); // [0,49)
int y = SNode.generate(35);
if (x == 0) {
x += 1;
} else if (x == 49) {
x -= 1;
}
if (y == 0) {
y += 1;
} else if (y == 34) {
y -= 1;
}
this.startx = ((int) Constant.rec.getX() + x * Constant.FOOD_WIDTH);
this.starty = ((int) Constant.rec.getY() + y * Constant.FOOD_HEIGHT);
this.snakeHead = new SNode(this.startx, this.starty, Color.GREEN);
nodes.add(snakeHead);
this.addNode(); // 默认是 2 个结点，需再增加 1 个结点
}
// 断定蛇是否与食物是否重叠:true: 重叠 ,false：不重叠
public boolean hit(SNode food) {
boolean result = false;
for (SNode snode : nodes) {
boolean res = snode.getRec().intersects(food.getRec());
if (res) {
result = true;
break;
}
}
return result;
}
// 吃食物
public boolean eat(SNode food) {
boolean result = false;
for (SNode snode : nodes) {
boolean res = snode.getRec().intersects(food.getRec());
if (res) {
result = true;
if (nodes.size() >= 2) {// 1. 初始相遇，2. 在挪动中相遇
this.addNode(); // 蛇的身材增长 1
}
break;
}
}
return result;
}
// 给蛇的尾部增加一个结点，与蛇方位无关
private void addNode() {
int size = nodes.size();
switch (dir) {
case Constant.L: // 向左走, 则左边增加第 2 个结点，且没有碰壁
if (size == 1) {// 蛇静止，须要增加一个结点到蛇尾
int x = this.startx + Constant.FOOD_WIDTH;
int y = this.starty;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(snode); // 增加到汇合开端
} else {
int x = this.startx – Constant.FOOD_WIDTH;
int y = this.starty;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(0, snode);
this.snakeHead = snode;
this.startx = x;
this.starty = y;
// 判断蛇头左越界
if (this.startx < Constant.rec.getX()) {
this.isLive = false;
}
}
break;
case Constant.R:
if (size == 1) {// 蛇静止，须要增加一个结点到蛇尾
int x = this.startx – Constant.FOOD_WIDTH;
int y = this.starty;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(snode); // 增加到汇合开端
} else {
int x = this.startx + Constant.FOOD_WIDTH;
int y = this.starty;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(0, snode);
this.snakeHead = snode;
this.startx = x;
this.starty = y;
// 判断蛇头右越界
if (this.startx > Constant.GAME_WIDTH) {
this.isLive = false;
}
}
break;
case Constant.U:
if (size == 1) {// 蛇静止，须要增加一个结点到蛇尾
int x = this.startx;
int y = this.starty + Constant.FOOD_HEIGHT;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(snode); // 增加到汇合开端
} else {
int x = this.startx;
int y = this.starty – Constant.FOOD_HEIGHT;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(0, snode);
this.snakeHead = snode;
this.startx = x;
this.starty = y;
// 判断蛇头上越界
if (this.starty < Constant.rec.getY()) {
this.isLive = false;
}
}
break;
case Constant.D:
if (size == 1) {// 蛇静止，须要增加一个结点到蛇尾
int x = this.startx;
int y = this.starty – Constant.FOOD_HEIGHT;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(snode); // 增加到汇合开端
} else {
int x = this.startx;
int y = this.starty + Constant.FOOD_HEIGHT;
// int y = this.starty + this.speed;
SNode snode = new SNode(x, y, Color.GREEN);
nodes.add(0, snode);
this.snakeHead = snode;
this.startx = x;
this.starty = y;
// 判断蛇头下越界
if (this.starty > ((int)Constant.rec.getY()+ Constant.GAME_HEIGHT-Constant.FOOD_HEIGHT)) {
this.isLive = false;
}
}
break;
}
}
public boolean isLive() {
return isLive;
}
// 蛇的挪动，一直变换蛇头，删除蛇尾
private void move() {
this.addNode(); // 再增加一个新结点，删除开端结点
int len = nodes.size();
nodes.remove(len – 1);
}
// 画蛇及蛇的挪动
public void paint(Graphics2D g2d) {
// 对 nodes 结点顺次绘制
g2d.setColor(this.snakeHead.getColor());
// 对蛇的身材进行绘制
for (SNode snode : nodes) {
g2d.fillRect(snode.getX(), snode.getY(), Constant.FOOD_WIDTH,
Constant.FOOD_HEIGHT);
}
this.move();
}
}
3，SNode 食物类
设计食物类也能够说是对蛇类的一个简化
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Rectangle;
// 食物类的定义：
public class SNode {
private int x,y; // 食物的起始坐标，与游戏的起始点关联
private Color color; // 食物的色彩
private Rectangle rec; // 食物的矩形区域
public Color getColor() {
return color;
}
public int getX() { // 读取数据
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public Rectangle getRec() {
return rec;
}
public void setRec(Rectangle rec) {
this.rec = rec;
}
// 随机产生某个地位的食物
public SNode(Color color) {
this.x = (int)Constant.rec.getX()+this.generate(50)*Constant.FOOD_WIDTH;
this.y = (int)Constant.rec.getY()+this.generate(35)*Constant.FOOD_HEIGHT;
this.rec = new Rectangle(this.x, this.y, Constant.FOOD_WIDTH, Constant.FOOD_HEIGHT);
this.color = color;
}
// 生成固定地位的结点，用于产生蛇头
public SNode(int x,int y,Color color) {
this.x = x;
this.y = y;
this.color = color;
this.rec = new Rectangle(this.x, this.y, Constant.FOOD_WIDTH, Constant.FOOD_HEIGHT);
}
// 随机产生数字
public static int generate(int number) {//[0,numbder)
int x = 0;
x = (int)(Math.random()*number);
return x;
}
// 定义画食物的办法：基于图形缓存画法 Graphics2D
public void paint(Graphics2D g2d) {
g2d.setColor(this.color);
g2d.fillRect(this.x, this.y, Constant.FOOD_WIDTH, Constant.FOOD_HEIGHT);
}
public static void main(String[] args) {
}
}
4，Constant 常量类
对须要应用到的常量保留下来，不便对整个界面的批改
import java.awt.Rectangle;
public class Constant {
public static final int FOOD_WIDTH = 15; // 食物的宽度和高度
public static final int FOOD_HEIGHT = 15;
public static final int GAME_WIDTH = FOOD_WIDTH*50;
public static final int GAME_HEIGHT = FOOD_HEIGHT*35;
public static final int JFRAME_WIDTH = FOOD_WIDTH*52;
public static final int JFRAME_HEIGHT = FOOD_HEIGHT*38+6;
public static final int L=1,R=2,U=3,D=4;
public static final int SNAKE_NORMAL = 500;
public static final int SNAKE_ADD = 180;
public static final int SNAKE_SUPER = 50;
public static final int SNAKE_SUB = 850;
// 游戏方格区域
public static final Rectangle rec = new Rectangle(FOOD_WIDTH, FOOD_HEIGHT*2+6, GAME_WIDTH, GAME_HEIGHT);
}