import java.util.Random;
 
 
 敌飞机: 是飞行物，也是敌人
 
public class Airplane extends FlyingObject implements Enemy {
    private int speed = 3;  //移动步骤
 
    /** 初始化数据 */
    public Airplane(){
        this.image = ShootGame.airplane;
        width = image.getWidth();
        height = image.getHeight();
        y = -height;         
        Random rand = new Random();
        x = rand.nextInt(ShootGame.WIDTH - width);
    }
 
    /** 获取分数 */
    @Override
    public int getScore() { 
        return 5;
    }
 
    /** //越界处理 */
    @Override
    public     boolean outOfBounds() {  
        return y>ShootGame.HEIGHT;
    }
 
    /** 移动 */
    @Override
    public void step() {  
        y += speed;
    }
 
}

/**
 * 奖励
 */ 
public interface Award { 
    int DOUBLE_FIRE = 0;  //双倍火力 
    int LIFE = 1;   //1条命 
    /** 获得奖励类型(上面的0或1) */ 
    int getType(); 
}

import java.util.Random; 
 
/** 蜜蜂 */ 
public class Bee extends FlyingObject implements Award{ 
    private int xSpeed = 1;   //x坐标移动速度 
    private int ySpeed = 2;   //y坐标移动速度 
    private int awardType;    //奖励类型 
 
    /** 初始化数据 */ 
    public Bee(){ 
        this.image = ShootGame.bee; 
        width = image.getWidth(); 
        height = image.getHeight(); 
        y = -height; 
        Random rand = new Random(); 
        x = rand.nextInt(ShootGame.WIDTH - width); 
        awardType = rand.nextInt(2);   //初始化时给奖励 
    } 
 
    /** 获得奖励类型 */ 
    public int getType(){ 
        return awardType; 
    } 
 
    /** 越界处理 */ 
    @Override 
    public boolean outOfBounds() { 
        return y>ShootGame.HEIGHT; 
    } 
 
    /** 移动，可斜着飞 */ 
    @Override 
    public void step() {       
        x += xSpeed; 
        y += ySpeed; 
        if(x > ShootGame.WIDTH-width){   
            xSpeed = -1; 
        } 
        if(x < 0){ 
            xSpeed = 1; 
        } 
    } 
}

/**
 * 子弹类:是飞行物
 */ 
public class Bullet extends FlyingObject { 
    private int speed = 3;  //移动的速度 
 
    /** 初始化数据 */ 
    public Bullet(int x,int y){ 
        this.x = x; 
        this.y = y; 
        this.image = ShootGame.bullet; 
    } 
 
    /** 移动 */ 
    @Override 
    public void step(){    
        y-=speed; 
    } 
 
    /** 越界处理 */ 
    @Override 
    public boolean outOfBounds() { 
        return y<-height; 
    } 
 
}

/**
 * 敌人，可以有分数
 */ 
public interface Enemy { 
    /** 敌人的分数  */ 
    int getScore(); 
}

import java.awt.image.BufferedImage; 
 
/**
 * 飞行物(敌机，蜜蜂，子弹，英雄机)
 */ 
public abstract class FlyingObject { 
    protected int x;    //x坐标 
    protected int y;    //y坐标 
    protected int width;    //宽 
    protected int height;   //高 
    protected BufferedImage image;   //图片 
 
    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 int getWidth() { 
        return width; 
    } 
 
    public void setWidth(int width) { 
        this.width = width; 
    } 
 
    public int getHeight() { 
        return height; 
    } 
 
    public void setHeight(int height) { 
        this.height = height; 
    } 
 
    public BufferedImage getImage() { 
        return image; 
    } 
 
    public void setImage(BufferedImage image) { 
        this.image = image; 
    } 
 
    /**
     * 检查是否出界
     * @return true 出界与否
     */ 
    public abstract boolean outOfBounds(); 
 
    /**
     * 飞行物移动一步
     */ 
    public abstract void step(); 
 
    /**
     * 检查当前飞行物体是否被子弹(x,y)击(shoot)中
     * @param Bullet 子弹对象
     * @return true表示被击中了
     */ 
    public boolean shootBy(Bullet bullet){ 
        int x = bullet.x;  //子弹横坐标 
        int y = bullet.y;  //子弹纵坐标 
        return this.x<x && x<this.x+width && this.y<y && y<this.y+height; 
    } 
 
}

import java.awt.image.BufferedImage; 
 
/**
 * 英雄机:是飞行物
 */ 
public class Hero extends FlyingObject{ 
 
    private BufferedImage[] images = {};  //英雄机图片 
    private int index = 0;                //英雄机图片切换索引 
 
    private int doubleFire;   //双倍火力 
    private int life;   //命 
 
    /** 初始化数据 */ 
    public Hero(){ 
        life = 3;   //初始3条命 
        doubleFire = 0;   //初始火力为0 
        images = new BufferedImage[]{ShootGame.hero0, ShootGame.hero1}; //英雄机图片数组 
        image = ShootGame.hero0;   //初始为hero0图片 
        width = image.getWidth(); 
        height = image.getHeight(); 
        x = 150; 
        y = 400; 
    } 
 
    /** 获取双倍火力 */ 
    public int isDoubleFire() { 
        return doubleFire; 
    } 
 
    /** 设置双倍火力 */ 
    public void setDoubleFire(int doubleFire) { 
        this.doubleFire = doubleFire; 
    } 
 
    /** 增加火力 */ 
    public void addDoubleFire(){ 
        doubleFire = 40; 
    } 
 
    /** 增命 */ 
    public void addLife(){  //增命 
        life++; 
    } 
 
    /** 减命 */ 
    public void subtractLife(){   //减命 
        life--; 
    } 
 
    /** 获取命 */ 
    public int getLife(){ 
        return life; 
    } 
 
    /** 当前物体移动了一下，相对距离，x,y鼠标位置  */ 
    public void moveTo(int x,int y){    
        this.x = x - width/2; 
        this.y = y - height/2; 
    } 
 
    /** 越界处理 */ 
    @Override 
    public boolean outOfBounds() { 
        return false;   
    } 
 
    /** 发射子弹 */ 
    public Bullet[] shoot(){    
        int xStep = width/4;      //4半 
        int yStep = 20;  //步 
        if(doubleFire>0){  //双倍火力 
            Bullet[] bullets = new Bullet[2]; 
            bullets[0] = new Bullet(x+xStep,y-yStep);  //y-yStep(子弹距飞机的位置) 
            bullets[1] = new Bullet(x+3*xStep,y-yStep); 
            return bullets; 
        }else{      //单倍火力 
            Bullet[] bullets = new Bullet[1]; 
            bullets[0] = new Bullet(x+2*xStep,y-yStep);   
            return bullets; 
        } 
    } 
 
    /** 移动 */ 
    @Override 
    public void step() { 
        if(images.length>0){ 
            image = images[index++/10%images.length];  //切换图片hero0，hero1 
        } 
    } 
 
    /** 碰撞算法 */ 
    public boolean hit(FlyingObject other){ 
 
        int x1 = other.x - this.width/2;                 //x坐标最小距离 
        int x2 = other.x + this.width/2 + other.width;   //x坐标最大距离 
        int y1 = other.y - this.height/2;                //y坐标最小距离 
        int y2 = other.y + this.height/2 + other.height; //y坐标最大距离 
 
        int herox = this.x + this.width/2;               //英雄机x坐标中心点距离 
        int heroy = this.y + this.height/2;              //英雄机y坐标中心点距离 
 
        return herox>x1 && herox<x2 && heroy>y1 && heroy<y2;   //区间范围内为撞上了 
    } 
 
}

import java.awt.Font; 
import java.awt.Color; 
import java.awt.Graphics; 
import java.awt.event.MouseAdapter; 
import java.awt.event.MouseEvent; 
import java.util.Arrays; 
import java.util.Random; 
import java.util.Timer; 
import java.util.TimerTask; 
import java.awt.image.BufferedImage; 
 
import javax.imageio.ImageIO; 
import javax.swing.ImageIcon; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
 
public class ShootGame extends JPanel { 
    public static final int WIDTH = 400; // 面板宽 
    public static final int HEIGHT = 654; // 面板高 
    /** 游戏的当前状态: START RUNNING PAUSE GAME_OVER */ 
    private int state; 
    private static final int START = 0; 
    private static final int RUNNING = 1; 
    private static final int PAUSE = 2; 
    private static final int GAME_OVER = 3; 
 
    private int score = 0; // 得分 
    private Timer timer; // 定时器 
    private int intervel = 1000 / 100; // 时间间隔(毫秒) 
 
    public static BufferedImage background; 
    public static BufferedImage start; 
    public static BufferedImage airplane; 
    public static BufferedImage bee; 
    public static BufferedImage bullet; 
    public static BufferedImage hero0; 
    public static BufferedImage hero1; 
    public static BufferedImage pause; 
    public static BufferedImage gameover; 
 
    private FlyingObject[] flyings = {}; // 敌机数组 
    private Bullet[] bullets = {}; // 子弹数组 
    private Hero hero = new Hero(); // 英雄机 
 
    static { // 静态代码块，初始化图片资源 
        try { 
            background = ImageIO.read(ShootGame.class 
                    .getResource("background.png")); 
            start = ImageIO.read(ShootGame.class.getResource("start.png")); 
            airplane = ImageIO 
                    .read(ShootGame.class.getResource("airplane.png")); 
            bee = ImageIO.read(ShootGame.class.getResource("bee.png")); 
            bullet = ImageIO.read(ShootGame.class.getResource("bullet.png")); 
            hero0 = ImageIO.read(ShootGame.class.getResource("hero0.png")); 
            hero1 = ImageIO.read(ShootGame.class.getResource("hero1.png")); 
            pause = ImageIO.read(ShootGame.class.getResource("pause.png")); 
            gameover = ImageIO 
                    .read(ShootGame.class.getResource("gameover.png")); 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } 
    } 
 
    /** 画 */ 
    @Override 
    public void paint(Graphics g) { 
        g.drawImage(background, 0, 0, null); // 画背景图 
        paintHero(g); // 画英雄机 
        paintBullets(g); // 画子弹 
        paintFlyingObjects(g); // 画飞行物 
        paintScore(g); // 画分数 
        paintState(g); // 画游戏状态 
    } 
 
    /** 画英雄机 */ 
    public void paintHero(Graphics g) { 
        g.drawImage(hero.getImage(), hero.getX(), hero.getY(), null); 
    } 
 
    /** 画子弹 */ 
    public void paintBullets(Graphics g) { 
        for (int i = 0; i < bullets.length; i++) { 
            Bullet b = bullets[i]; 
            g.drawImage(b.getImage(), b.getX() - b.getWidth() / 2, b.getY(), 
                    null); 
        } 
    } 
 
    /** 画飞行物 */ 
    public void paintFlyingObjects(Graphics g) { 
        for (int i = 0; i < flyings.length; i++) { 
            FlyingObject f = flyings[i]; 
            g.drawImage(f.getImage(), f.getX(), f.getY(), null); 
        } 
    } 
 
    /** 画分数 */ 
    public void paintScore(Graphics g) { 
        int x = 10; // x坐标 
        int y = 25; // y坐标 
        Font font = new Font(Font.SANS_SERIF, Font.BOLD, 22); // 字体 
        g.setColor(new Color(0xFF0000)); 
        g.setFont(font); // 设置字体 
        g.drawString("SCORE:" + score, x, y); // 画分数 
        y=y+20; // y坐标增20 
        g.drawString("LIFE:" + hero.getLife(), x, y); // 画命 
    } 
 
    /** 画游戏状态 */ 
    public void paintState(Graphics g) { 
        switch (state) { 
        case START: // 启动状态 
            g.drawImage(start, 0, 0, null); 
            break; 
        case PAUSE: // 暂停状态 
            g.drawImage(pause, 0, 0, null); 
            break; 
        case GAME_OVER: // 游戏终止状态 
            g.drawImage(gameover, 0, 0, null); 
            break; 
        } 
    } 
 
    public static void main(String[] args) { 
        JFrame frame = new JFrame("Fly"); 
        ShootGame game = new ShootGame(); // 面板对象 
        frame.add(game); // 将面板添加到JFrame中 
        frame.setSize(WIDTH, HEIGHT); // 设置大小 
        frame.setAlwaysOnTop(true); // 设置其总在最上 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 默认关闭操作 
        frame.setIconImage(new ImageIcon("images/icon.jpg").getImage()); // 设置窗体的图标 
        frame.setLocationRelativeTo(null); // 设置窗体初始位置 
        frame.setVisible(true); // 尽快调用paint 
 
        game.action(); // 启动执行 
    } 
 
    /** 启动执行代码 */ 
    public void action() { 
        // 鼠标监听事件 
        MouseAdapter l = new MouseAdapter() { 
            @Override 
            public void mouseMoved(MouseEvent e) { // 鼠标移动 
                if (state == RUNNING) { // 运行状态下移动英雄机--随鼠标位置 
                    int x = e.getX(); 
                    int y = e.getY(); 
                    hero.moveTo(x, y); 
                } 
            } 
 
            @Override 
            public void mouseEntered(MouseEvent e) { // 鼠标进入 
                if (state == PAUSE) { // 暂停状态下运行 
                    state = RUNNING; 
                } 
            } 
 
            @Override 
            public void mouseExited(MouseEvent e) { // 鼠标退出 
                if (state == RUNNING) { // 游戏未结束，则设置其为暂停 
                    state = PAUSE; 
                } 
            } 
 
            @Override 
            public void mouseClicked(MouseEvent e) { // 鼠标点击 
                switch (state) { 
                case START: 
                    state = RUNNING; // 启动状态下运行 
                    break; 
                case GAME_OVER: // 游戏结束，清理现场 
                    flyings = new FlyingObject[0]; // 清空飞行物 
                    bullets = new Bullet[0]; // 清空子弹 
                    hero = new Hero(); // 重新创建英雄机 
                    score = 0; // 清空成绩 
                    state = START; // 状态设置为启动 
                    break; 
                } 
            } 
        }; 
        this.addMouseListener(l); // 处理鼠标点击操作 
        this.addMouseMotionListener(l); // 处理鼠标滑动操作 
 
        timer = new Timer(); // 主流程控制 
        timer.schedule(new TimerTask() { 
            @Override 
            public void run() { 
                if (state == RUNNING) { // 运行状态 
                    enterAction(); // 飞行物入场 
                    stepAction(); // 走一步 
                    shootAction(); // 英雄机射击 
                    bangAction(); // 子弹打飞行物 
                    outOfBoundsAction(); // 删除越界飞行物及子弹 
                    checkGameOverAction(); // 检查游戏结束 
                } 
                repaint(); // 重绘，调用paint()方法 
            } 
 
        }, intervel, intervel); 
    } 
 
    int flyEnteredIndex = 0; // 飞行物入场计数 
 
    /** 飞行物入场 */ 
    public void enterAction() { 
        flyEnteredIndex++; 
        if (flyEnteredIndex % 40 == 0) { // 400毫秒生成一个飞行物--10*40 
            FlyingObject obj = nextOne(); // 随机生成一个飞行物 
            flyings = Arrays.copyOf(flyings, flyings.length + 1); 
            flyings[flyings.length - 1] = obj; 
        } 
    } 
 
    /** 走一步 */ 
    public void stepAction() { 
        for (int i = 0; i < flyings.length; i++) { // 飞行物走一步 
            FlyingObject f = flyings[i]; 
            f.step(); 
        } 
 
        for (int i = 0; i < bullets.length; i++) { // 子弹走一步 
            Bullet b = bullets[i]; 
            b.step(); 
        } 
        hero.step(); // 英雄机走一步 
    } 
 
    /** 飞行物走一步 */ 
    public void flyingStepAction() { 
        for (int i = 0; i < flyings.length; i++) { 
            FlyingObject f = flyings[i]; 
            f.step(); 
        } 
    } 
 
    int shootIndex = 0; // 射击计数 
 
    /** 射击 */ 
    public void shootAction() { 
        shootIndex++; 
        if (shootIndex % 30 == 0) { // 300毫秒发一颗 
            Bullet[] bs = hero.shoot(); // 英雄打出子弹 
            bullets = Arrays.copyOf(bullets, bullets.length + bs.length); // 扩容 
            System.arraycopy(bs, 0, bullets, bullets.length - bs.length, 
                    bs.length); // 追加数组 
        } 
    } 
 
    /** 子弹与飞行物碰撞检测 */ 
    public void bangAction() { 
        for (int i = 0; i < bullets.length; i++) { // 遍历所有子弹 
            Bullet b = bullets[i]; 
            bang(b); // 子弹和飞行物之间的碰撞检查 
        } 
    } 
 
    /** 删除越界飞行物及子弹 */ 
    public void outOfBoundsAction() { 
        int index = 0; // 索引 
        FlyingObject[] flyingLives = new FlyingObject[flyings.length]; // 活着的飞行物 
        for (int i = 0; i < flyings.length; i++) { 
            FlyingObject f = flyings[i]; 
            if (!f.outOfBounds()) { 
                flyingLives[index++] = f; // 不越界的留着 
            } 
        } 
        flyings = Arrays.copyOf(flyingLives, index); // 将不越界的飞行物都留着 
 
        index = 0; // 索引重置为0 
        Bullet[] bulletLives = new Bullet[bullets.length]; 
        for (int i = 0; i < bullets.length; i++) { 
            Bullet b = bullets[i]; 
            if (!b.outOfBounds()) { 
                bulletLives[index++] = b; 
            } 
        } 
        bullets = Arrays.copyOf(bulletLives, index); // 将不越界的子弹留着 
    } 
 
    /** 检查游戏结束 */ 
    public void checkGameOverAction() { 
        if (isGameOver()==true) { 
            state = GAME_OVER; // 改变状态 
        } 
    } 
 
    /** 检查游戏是否结束 */ 
    public boolean isGameOver() { 
 
        for (int i = 0; i < flyings.length; i++) { 
            int index = -1; 
            FlyingObject obj = flyings[i]; 
            if (hero.hit(obj)) { // 检查英雄机与飞行物是否碰撞 
                hero.subtractLife(); // 减命 
                hero.setDoubleFire(0); // 双倍火力解除 
                index = i; // 记录碰上的飞行物索引 
            } 
            if (index != -1) { 
                FlyingObject t = flyings[index]; 
                flyings[index] = flyings[flyings.length - 1]; 
                flyings[flyings.length - 1] = t; // 碰上的与最后一个飞行物交换 
 
                flyings = Arrays.copyOf(flyings, flyings.length - 1); // 删除碰上的飞行物 
            } 
        } 
 
        return hero.getLife() <= 0; 
    } 
 
    /** 子弹和飞行物之间的碰撞检查 */ 
    public void bang(Bullet bullet) { 
        int index = -1; // 击中的飞行物索引 
        for (int i = 0; i < flyings.length; i++) { 
            FlyingObject obj = flyings[i]; 
            if (obj.shootBy(bullet)) { // 判断是否击中 
                index = i; // 记录被击中的飞行物的索引 
                break; 
            } 
        } 
        if (index != -1) { // 有击中的飞行物 
            FlyingObject one = flyings[index]; // 记录被击中的飞行物 
 
            FlyingObject temp = flyings[index]; // 被击中的飞行物与最后一个飞行物交换 
            flyings[index] = flyings[flyings.length - 1]; 
            flyings[flyings.length - 1] = temp; 
 
            flyings = Arrays.copyOf(flyings, flyings.length - 1); // 删除最后一个飞行物(即被击中的) 
 
            // 检查one的类型(敌人加分，奖励获取) 
            if (one instanceof Enemy) { // 检查类型，是敌人，则加分 
                Enemy e = (Enemy) one; // 强制类型转换 
                score += e.getScore(); // 加分 
            } else { // 若为奖励，设置奖励 
                Award a = (Award) one; 
                int type = a.getType(); // 获取奖励类型 
                switch (type) { 
                case Award.DOUBLE_FIRE: 
                    hero.addDoubleFire(); // 设置双倍火力 
                    break; 
                case Award.LIFE: 
                    hero.addLife(); // 设置加命 
                    break; 
                } 
            } 
        } 
    } 
 
    /**
     * 随机生成飞行物
     * 
     * @return 飞行物对象
     */ 
    public static FlyingObject nextOne() { 
        Random random = new Random(); 
        int type = random.nextInt(20); // [0,20) 
        if (type < 4) { 
            return new Bee(); 
        } else { 
            return new Airplane(); 
        } 
    } 
 
}