import java.awt.image.BufferedImage;
 
/**
 * 飛行物(敵機(jī)，蜜蜂，子彈，英雄機(jī))
 */
public abstract class FlyingObject {
 protected int x; //x坐標(biāo)
 protected int y; //y坐標(biāo)
 protected int width; //寬
 protected int height; //高
 protected BufferedImage image; //圖片
 
 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;
 }
 
 /**
 * 檢查是否出界
 * @return true 出界與否
 */
 public abstract boolean outOfBounds();
 
 /**
 * 飛行物移動(dòng)一步
 */
 public abstract void step();
 
 /**
 * 檢查當(dāng)前飛行物體是否被子彈(x,y)擊(shoot)中
 * @param Bullet 子彈對(duì)象
 * @return true表示被擊中了
 */
 public boolean shootBy(Bullet bullet){
 int x = bullet.x; //子彈橫坐標(biāo)
 int y = bullet.y; //子彈縱坐標(biāo)
 return this.x<x && x<this.x+width && this.y<y && y<this.y+height;
 }
 
}

import java.awt.image.BufferedImage;
 
/**
 * 英雄機(jī):是飛行物
 */
public class Hero extends FlyingObject{
 
 private BufferedImage[] images = {}; //英雄機(jī)圖片
 private int index = 0;  //英雄機(jī)圖片切換索引
 
 private int doubleFire; //雙倍火力
 private int life; //命
 
 /** 初始化數(shù)據(jù) */
 public Hero(){
 life = 3; //初始3條命
 doubleFire = 0; //初始火力為0
 images = new BufferedImage[]{ShootGame.hero0, ShootGame.hero1}; //英雄機(jī)圖片數(shù)組
 image = ShootGame.hero0; //初始為hero0圖片
 width = image.getWidth();
 height = image.getHeight();
 x = 150;
 y = 400;
 }
 
 /** 獲取雙倍火力 */
 public int isDoubleFire() {
 return doubleFire;
 }
 
 /** 設(shè)置雙倍火力 */
 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++;
 }
 
 /** 減命 */
 public void subtractLife(){ //減命
 life--;
 }
 
 /** 獲取命 */
 public int getLife(){
 return life;
 }
 
 /** 當(dāng)前物體移動(dòng)了一下，相對(duì)距離，x,y鼠標(biāo)位置 */
 public void moveTo(int x,int y){ 
 this.x = x - width/2;
 this.y = y - height/2;
 }
 
 /** 越界處理 */
 @Override
 public boolean outOfBounds() {
 return false; 
 }
 
 /** 發(fā)射子彈 */
 public Bullet[] shoot(){ 
 int xStep = width/4; //4半
 int yStep = 20; //步
 if(doubleFire>0){ //雙倍火力
  Bullet[] bullets = new Bullet[2];
  bullets[0] = new Bullet(x+xStep,y-yStep); //y-yStep(子彈距飛機(jī)的位置)
  bullets[1] = new Bullet(x+3*xStep,y-yStep);
  return bullets;
 }else{ //單倍火力
  Bullet[] bullets = new Bullet[1];
  bullets[0] = new Bullet(x+2*xStep,y-yStep); 
  return bullets;
 }
 }
 
 /** 移動(dòng) */
 @Override
 public void step() {
 if(images.length>0){
  image = images[index++/10%images.length]; //切換圖片hero0，hero1
 }
 }
 
 /** 碰撞算法 */
 public boolean hit(FlyingObject other){
 
 int x1 = other.x - this.width/2;   //x坐標(biāo)最小距離
 int x2 = other.x + this.width/2 + other.width; //x坐標(biāo)最大距離
 int y1 = other.y - this.height/2;  //y坐標(biāo)最小距離
 int y2 = other.y + this.height/2 + other.height; //y坐標(biāo)最大距離
 
 int herox = this.x + this.width/2;  //英雄機(jī)x坐標(biāo)中心點(diǎn)距離
 int heroy = this.y + this.height/2;  //英雄機(jī)y坐標(biāo)中心點(diǎn)距離
 
 return herox>x1 && herox<x2 && heroy>y1 && heroy<y2; //區(qū)間范圍內(nèi)為撞上了
 }
 
}

/**
 * 敵人，可以有分?jǐn)?shù)
 */
public interface Enemy {
 /** 敵人的分?jǐn)?shù) */
 int getScore();
}

/**
 * 獎(jiǎng)勵(lì)
 */
public interface Award {
 int DOUBLE_FIRE = 0; //雙倍火力
 int LIFE = 1; //1條命
 /** 獲得獎(jiǎng)勵(lì)類型(上面的0或1) */
 int getType();
}

import java.util.Random;
 
/**
 * 敵飛機(jī): 是飛行物，也是敵人
 */
public class Airplane extends FlyingObject implements Enemy {
 private int speed = 3; //移動(dòng)步驟
 
 /** 初始化數(shù)據(jù) */
 public Airplane(){
 this.image = ShootGame.airplane;
 width = image.getWidth();
 height = image.getHeight();
 y = -height;  
 Random rand = new Random();
 x = rand.nextInt(ShootGame.WIDTH - width);
 }
 
 /** 獲取分?jǐn)?shù) */
 @Override
 public int getScore() { 
 return 5;
 }
 
 /** //越界處理 */
 @Override
 public boolean outOfBounds() { 
 return y>ShootGame.HEIGHT;
 }
 
 /** 移動(dòng) */
 @Override
 public void step() { 
 y += speed;
 }
 
}

import java.util.Random;
 
/** 蜜蜂 */
public class Bee extends FlyingObject implements Award{
 private int xSpeed = 1; //x坐標(biāo)移動(dòng)速度
 private int ySpeed = 2; //y坐標(biāo)移動(dòng)速度
 private int awardType; //獎(jiǎng)勵(lì)類型
 
 /** 初始化數(shù)據(jù) */
 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); //初始化時(shí)給獎(jiǎng)勵(lì)
 }
 
 /** 獲得獎(jiǎng)勵(lì)類型 */
 public int getType(){
 return awardType;
 }
 
 /** 越界處理 */
 @Override
 public boolean outOfBounds() {
 return y>ShootGame.HEIGHT;
 }
 
 /** 移動(dòng)，可斜著飛 */
 @Override
 public void step() { 
 x += xSpeed;
 y += ySpeed;
 if(x > ShootGame.WIDTH-width){ 
  xSpeed = -1;
 }
 if(x < 0){
  xSpeed = 1;
 }
 }
}

 /**
 * 子彈類:是飛行物
 */
public class Bullet extends FlyingObject {
 private int speed = 3; //移動(dòng)的速度
 
 /** 初始化數(shù)據(jù) */
 public Bullet(int x,int y){
 this.x = x;
 this.y = y;
 this.image = ShootGame.bullet;
 }
 
 /** 移動(dòng) */
 @Override
 public void step(){ 
 y-=speed;
 }
 
 /** 越界處理 */
 @Override
 public boolean outOfBounds() {
 return y<-height;
 }
 
}

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 void main(String[] args) {
 JFrame frame = new JFrame("Fly");
 ShootGame game = new ShootGame(); // 面板對(duì)象
 frame.add(game); // 將面板添加到JFrame中
 frame.setSize(WIDTH, HEIGHT); // 設(shè)置大小
 frame.setAlwaysOnTop(true); // 設(shè)置其總在最上
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 默認(rèn)關(guān)閉操作
 frame.setIconImage(new ImageIcon("images/icon.jpg").getImage()); // 設(shè)置窗體的圖標(biāo)
 frame.setLocationRelativeTo(null); // 設(shè)置窗體初始位置
 frame.setVisible(true); // 盡快調(diào)用paint
 
 game.action(); // 啟動(dòng)執(zhí)行
 }
 public static final int WIDTH = 400; // 面板寬
 public static final int HEIGHT = 654; // 面板高
 /** 游戲的當(dāng)前狀態(tài): 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; // 定時(shí)器
 private int intervel = 1000 / 100; // 時(shí)間間隔(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 = {}; // 敵機(jī)數(shù)組
 private Bullet[] bullets = {}; // 子彈數(shù)組
 private Hero hero = new Hero(); // 英雄機(jī)
 
 static { // 靜態(tài)代碼塊，初始化圖片資源
 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();
 }
 }
 
 /** 畫(huà) */
 @Override
 public void paint(Graphics g) {
 g.drawImage(background, 0, 0, null); // 畫(huà)背景圖
 paintHero(g); // 畫(huà)英雄機(jī)
 paintBullets(g); // 畫(huà)子彈
 paintFlyingObjects(g); // 畫(huà)飛行物
 paintScore(g); // 畫(huà)分?jǐn)?shù)
 paintState(g); // 畫(huà)游戲狀態(tài)
 }
 
 /** 畫(huà)英雄機(jī) */
 public void paintHero(Graphics g) {
 g.drawImage(hero.getImage(), hero.getX(), hero.getY(), null);
 }
 
 /** 畫(huà)子彈 */
 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);
 }
 }
 
 /** 畫(huà)飛行物 */
 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);
 }
 }
 
 /** 畫(huà)分?jǐn)?shù) */
 public void paintScore(Graphics g) {
 int x = 10; // x坐標(biāo)
 int y = 25; // y坐標(biāo)
 Font font = new Font(Font.SANS_SERIF, Font.BOLD, 14); // 字體
 g.setColor(new Color(0x3A3B3B));
 g.setFont(font); // 設(shè)置字體
 g.drawString("SCORE:" + score, x, y); // 畫(huà)分?jǐn)?shù)
 y += 20; // y坐標(biāo)增20
 g.drawString("LIFE:" + hero.getLife(), x, y); // 畫(huà)命
 }
 
 /** 畫(huà)游戲狀態(tài) */
 public void paintState(Graphics g) {
 switch (state) {
 case START: // 啟動(dòng)狀態(tài)
  g.drawImage(start, 0, 0, null);
  break;
 case PAUSE: // 暫停狀態(tài)
  g.drawImage(pause, 0, 0, null);
  break;
 case GAME_OVER: // 游戲終止?fàn)顟B(tài)
  g.drawImage(gameover, 0, 0, null);
  break;
 }
 }
 
 
 /** 啟動(dòng)執(zhí)行代碼 */
 public void action() {
 // 鼠標(biāo)監(jiān)聽(tīng)事件
 MouseAdapter l = new MouseAdapter() {
  @Override
  public void mouseMoved(MouseEvent e) { // 鼠標(biāo)移動(dòng)
  if (state == RUNNING) { // 運(yùn)行狀態(tài)下移動(dòng)英雄機(jī)--隨鼠標(biāo)位置
   int x = e.getX();
   int y = e.getY();
   hero.moveTo(x, y);
  }
  }
 
  @Override
  public void mouseEntered(MouseEvent e) { // 鼠標(biāo)進(jìn)入
  if (state == PAUSE) { // 暫停狀態(tài)下運(yùn)行
   state = RUNNING;
  }
  }
 
  @Override
  public void mouseExited(MouseEvent e) { // 鼠標(biāo)退出
  if (state != GAME_OVER&&state!=START) { // 游戲未結(jié)束，則設(shè)置其為暫停
   state = PAUSE;
  }
  }
 
  @Override
  public void mouseClicked(MouseEvent e) { // 鼠標(biāo)點(diǎn)擊
  switch (state) {
  case START:
   state = RUNNING; // 啟動(dòng)狀態(tài)下運(yùn)行
   break;
  case GAME_OVER: // 游戲結(jié)束，清理現(xiàn)場(chǎng)
   flyings = new FlyingObject[0]; // 清空飛行物
   bullets = new Bullet[0]; // 清空子彈
   hero = new Hero(); // 重新創(chuàng)建英雄機(jī)
   score = 0; // 清空成績(jī)
   state = START; // 狀態(tài)設(shè)置為啟動(dòng)
   break;
  }
  }
 };
 this.addMouseListener(l); // 處理鼠標(biāo)點(diǎn)擊操作
 this.addMouseMotionListener(l); // 處理鼠標(biāo)滑動(dòng)操作
 
 timer = new Timer(); // 主流程控制
 timer.schedule(new TimerTask() {
  @Override
  public void run() {
  if (state == RUNNING) { // 運(yùn)行狀態(tài)
   enterAction(); // 飛行物入場(chǎng)
   stepAction(); // 走一步
   shootAction(); // 英雄機(jī)射擊
   bangAction(); // 子彈打飛行物
   outOfBoundsAction(); // 刪除越界飛行物及子彈
   checkGameOverAction(); // 檢查游戲結(jié)束
  }
  repaint(); // 重繪，調(diào)用paint()方法
  }
 
 }, intervel, intervel);
 }
 
 int flyEnteredIndex = 0; // 飛行物入場(chǎng)計(jì)數(shù)
 
 /** 飛行物入場(chǎng) */
 public void enterAction() {
 flyEnteredIndex++;
 if (flyEnteredIndex % 40 == 0) { // 400毫秒生成一個(gè)飛行物--10*40
  FlyingObject obj = nextOne(); // 隨機(jī)生成一個(gè)飛行物
  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++) { // 飛行物走一步
  FlyingObject f = flyings[i];
  f.step();
 }
 
 for (int i = 0; i < bullets.length; i++) { // 子彈走一步
  Bullet b = bullets[i];
  b.step();
 }
 hero.step(); // 英雄機(jī)走一步
 }
 
 /** 飛行物走一步 */
 public void flyingStepAction() {
 for (int i = 0; i < flyings.length; i++) {
  FlyingObject f = flyings[i];
  f.step();
 }
 }
 
 int shootIndex = 0; // 射擊計(jì)數(shù)
 
 /** 射擊 */
 public void shootAction() {
 shootIndex++;
 if (shootIndex % 30 == 0) { // 300毫秒發(fā)一顆
  Bullet[] bs = hero.shoot(); // 英雄打出子彈
  bullets = Arrays.copyOf(bullets, bullets.length + bs.length); // 擴(kuò)容
  System.arraycopy(bs, 0, bullets, bullets.length - bs.length,
   bs.length); // 追加數(shù)組
 }
 }
 
 /** 子彈與飛行物碰撞檢測(cè) */
 public void bangAction() {
 for (int i = 0; i < bullets.length; i++) { // 遍歷所有子彈
  Bullet b = bullets[i];
  bang(b); // 子彈和飛行物之間的碰撞檢查
 }
 }
 
 /** 刪除越界飛行物及子彈 */
 public void outOfBoundsAction() {
 int index = 0; // 索引
 FlyingObject[] flyingLives = new FlyingObject[flyings.length]; // 活著的飛行物
 for (int i = 0; i < flyings.length; i++) {
  FlyingObject f = flyings[i];
  if (!f.outOfBounds()) {
  flyingLives[index++] = f; // 不越界的留著
  }
 }
 flyings = Arrays.copyOf(flyingLives, index); // 將不越界的飛行物都留著
 
 index = 0; // 索引重置為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); // 將不越界的子彈留著
 }
 
 /** 檢查游戲結(jié)束 */
 public void checkGameOverAction() {
 if (isGameOver()) {
  state = GAME_OVER; // 改變狀態(tài)
 }
 }
 
 /** 檢查游戲是否結(jié)束 */
 public boolean isGameOver() {
 
 for (int i = 0; i < flyings.length; i++) {
  int index = -1;
  FlyingObject obj = flyings[i];
  if (hero.hit(obj)) { // 檢查英雄機(jī)與飛行物是否碰撞
  hero.subtractLife(); // 減命
  hero.setDoubleFire(0); // 雙倍火力解除
  index = i; // 記錄碰上的飛行物索引
  }
  if (index != -1) {
  FlyingObject t = flyings[index];
  flyings[index] = flyings[flyings.length - 1];
  flyings[flyings.length - 1] = t; // 碰上的與最后一個(gè)飛行物交換
 
  flyings = Arrays.copyOf(flyings, flyings.length - 1); // 刪除碰上的飛行物
  }
 }
 
 return hero.getLife() <= 0;
 }
 
 /** 子彈和飛行物之間的碰撞檢查 */
 public void bang(Bullet bullet) {
 int index = -1; // 擊中的飛行物索引
 for (int i = 0; i < flyings.length; i++) {
  FlyingObject obj = flyings[i];
  if (obj.shootBy(bullet)) { // 判斷是否擊中
  index = i; // 記錄被擊中的飛行物的索引
  break;
  }
 }
 if (index != -1) { // 有擊中的飛行物
  FlyingObject one = flyings[index]; // 記錄被擊中的飛行物
 
  FlyingObject temp = flyings[index]; // 被擊中的飛行物與最后一個(gè)飛行物交換
  flyings[index] = flyings[flyings.length - 1];
  flyings[flyings.length - 1] = temp;
 
  flyings = Arrays.copyOf(flyings, flyings.length - 1); // 刪除最后一個(gè)飛行物(即被擊中的)
 
  // 檢查one的類型(敵人加分，獎(jiǎng)勵(lì)獲取)
  if (one instanceof Enemy) { // 檢查類型，是敵人，則加分
  Enemy e = (Enemy) one; // 強(qiáng)制類型轉(zhuǎn)換
  score += e.getScore(); // 加分
  } else if (one instanceof Award) { // 若為獎(jiǎng)勵(lì)，設(shè)置獎(jiǎng)勵(lì)
  Award a = (Award) one;
  int type = a.getType(); // 獲取獎(jiǎng)勵(lì)類型
  switch (type) {
  case Award.DOUBLE_FIRE:
   hero.addDoubleFire(); // 設(shè)置雙倍火力
   break;
  case Award.LIFE:
   hero.addLife(); // 設(shè)置加命
   break;
  }
  }
 }
 }
 
 /**
 * 隨機(jī)生成飛行物
 * 
 * @return 飛行物對(duì)象
 */
 public static FlyingObject nextOne() {
 Random random = new Random();
 int type = random.nextInt(20); // [0,20)
 if (type == 0) {
  return new Bee();
 } else {
  return new Airplane();
 }
 }
 
}