GUI编程-贪吃蛇小游戏

【狂神说Java】GUI编程入门到游戏实战
https://www.bilibili.com/video/BV1DJ411B75F

主要逻辑

1. 定义数据
2. 初始化数据
   init()
3. 在画板上画出组件
   paintComponent(Graphics g)
4. 编辑监听事件，分为键盘监听事件和事件监听
   keyPressed(KeyEvent e)
actionPerformed(ActionEvent e)

package com.harbin.snake;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;

public class GamePanel extends JPanel implements KeyListener , ActionListener {
     
    //绘制面板，游戏中所有东西都用这个画笔来画
    //定义蛇的数据结构
    int length; //长度
    int[] snakeX = new int[600];
    int[] snakeY = new int[500];
    //蛇的方向
    String fx;

    //食物的坐标
    int foodX;
    int foodY;
    Random random = new Random();

    //当前游戏状态，开始 停止
    boolean isStart = false;

    //游戏失败
    boolean isFail = false;

    //成绩
    int score;

    //定时器
    Timer timer = new Timer(200,this);

    public GamePanel() {
     
        init();
        this.setFocusable(true);//获得焦点事件
        this.addKeyListener(this);//获得键盘监听事件
        timer.start();//游戏开始定时器就启动
    }

    public void init(){
     
        length = 3;
        snakeX[0] = 100;snakeY[0]=100;
        snakeX[1] = 75;snakeY[1]=100;
        snakeX[2] = 50;snakeY[2]=100;
        fx = "R";//初始化方向向右

        //食物随机放在屏幕
        foodX = 25 + 25*random.nextInt(34);
        foodY = 75 + 25*random.nextInt(24);

        //初始化成绩
        score = 0;

    }

    @Override
    protected void paintComponent(Graphics g) {
     
        super.paintComponent(g);//清屏
        //绘制静态面板
        this.setBackground(Color.WHITE);
        //参数（画到哪里：this当前面板，用什么画：画笔参数g，画的位置：x,y）
        Data.header.paintIcon(this,g,25,11); //头部广告
        g.fillRect(25,75,850,600);//游戏界面

        //画积分
        g.setColor(Color.WHITE);
        g.setFont(new Font("微软雅黑",Font.BOLD,18));
        g.drawString("长度"+length,750,30);
        g.drawString("分数"+score,750,55);

        //画食物
        Data.food.paintIcon(this,g,foodX,foodY);

        //画蛇头，初始化蛇头向右，需要通过方向判断
        if (fx.equals("R")){
     
            Data.right.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("L")){
     
            Data.left.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("U")){
     
            Data.up.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("D")){
     
            Data.down.paintIcon(this,g,snakeX[0],snakeY[0]);
        }
        //画身体
        for (int i = 1; i < length; i++) {
     
            Data.body.paintIcon(this,g,snakeX[i],snakeY[i]);
        }

        //游戏状态
        if (!isStart){
     
            g.setColor(Color.WHITE);
            g.setFont(new Font("微软雅黑",Font.BOLD,40));
            g.drawString("按下空格开始游戏",300,300);
        }

        if (isFail){
     
            g.setColor(Color.RED);
            g.setFont(new Font("微软雅黑",Font.BOLD,40));
            g.drawString("游戏失败，按下空格重新开始",300,300);
        }

    }

    //键盘监听事件
    @Override
    public void keyPressed(KeyEvent e) {
     
        int keyCode = e.getKeyCode();//获取按下的键
        System.out.println(keyCode);
        if (keyCode == KeyEvent.VK_SPACE){
      //如果按下空格键
            if (isFail){
     
                isFail = false;
                init();
            }else {
     
                isStart = !isStart;
            }

            repaint();
        }

        //小蛇移动
        if (keyCode == KeyEvent.VK_UP){
     
            fx = "U";
        }else if (keyCode == KeyEvent.VK_DOWN){
     
            fx = "D";
        }else if (keyCode == KeyEvent.VK_LEFT){
     
            fx = "L";
        }else if (keyCode == KeyEvent.VK_RIGHT){
     
            fx = "R";
        }


    }

    //事件监听-通过定时事件刷新
    @Override
    public void actionPerformed(ActionEvent e) {
     
        if (isStart && !isFail){
     
            //吃食物 头和食物坐标重合
            if (snakeX[0] == foodX && snakeY[0] == foodY){
     
                //长度+1
                length++;
                //分数+10
                score += 10;
                //再次生成食物
                foodX = 25 + 25*random.nextInt(34);
                foodY = 75 + 25*random.nextInt(24);
            }


            //走向
            for (int i = length-1; i > 0 ; i--) {
     
                snakeX[i] = snakeX[i-1];
                snakeY[i] = snakeY[i-1];
            }

            //走向
            if (fx.equals("R")){
     
                snakeX[0] += 25;
                if (snakeX[0] > 850){
     snakeX[0] = 25;}//边界判断
            }else if (fx.equals("L")){
     
                snakeX[0] -= 25;
                if (snakeX[0] < 25){
     snakeX[0] = 850;}//边界判断
            }else if (fx.equals("U")){
     
                snakeY[0] -= 25;
                if (snakeY[0] < 75){
     snakeY[0] = 650;}//边界判断
            }else if (fx.equals("D")){
     
                snakeY[0] += 25;
                if (snakeY[0] > 650){
     snakeY[0] = 75;}//边界判断
            }

            //失败判断，撞到自己就算失败
            for (int i = 1; i < length; i++) {
     
                if (snakeX[0] == snakeX[i] && snakeY[0] == snakeY[i]){
     isFail=true;}
            }
            repaint();
        }
        timer.start();
    }
    @Override
    public void keyTyped(KeyEvent e) {
     }
    @Override
    public void keyReleased(KeyEvent e) {
     }
}

游戏启动入口

package com.harbin.snake;

import javax.swing.*;

public class StartGame {
     
    public static void main(String[] args) {
     
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        frame.setBounds(10,10,900,720);
        frame.setResizable(false);

        //游戏界面放入画板
        frame.add(new GamePanel());

        //一定放在下面，否则监听事件无效
        frame.setVisible(true);

    }
}

将以下文件放进项目目录的statics包下