hcanvas.java

小鸡过街

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import java.io.*;
import javax.microedition.media.*;

public class HCanvas extends GameCanvas implements Runnable {
  private Display  display;
  private boolean  sleeping;
  private long     frameDelay;
  private int      inputDelay;
  private Image    background;
  private Image    chickenHead;
  private Sprite   chickenSprite;
  private Sprite[] carSprite = new Sprite[4];
  private int[]    carYSpeed = new int[4];
  private boolean  gameOver;
  private int      numLives;
  private int      score;
  private Player   musicPlayer;
  private Player   celebratePlayer;
  private Player   squishPlayer;
  private Player   gameoverPlayer;

  public HCanvas(Display d) {
    super(true);
    display = d;

    // 设置流速率为20
    frameDelay = 10;

    // 设置输入延时
    inputDelay = 0;
  }
  
  public void start() {
    // 设置显示界面
    display.setCurrent(this);

    // 初始化游戏
    gameOver = false;
    numLives = 3;
    score = 0;

    // 设置背景图片和小车的图片
    try {
      background = Image.createImage("/Highway.png");
      chickenHead = Image.createImage("/ChickenHead.png");

      chickenSprite = new Sprite(Image.createImage("/Chicken.png"), 22, 22);
      chickenSprite.setPosition(2, 77);

      carSprite[0] = new Sprite(Image.createImage("/Car1.png"));
      carSprite[0].setPosition(40, 0);
      carYSpeed[0] = 3;
      carSprite[1] = new Sprite(Image.createImage("/Car2.png"));
      carSprite[1].setPosition(85, 0);
      carYSpeed[1] = 1;
      carSprite[2] = new Sprite(Image.createImage("/Car3.png"));
      carSprite[2].setPosition(130, 67);
      carYSpeed[2] = -2;
      carSprite[3] = new Sprite(Image.createImage("/Car4.png"));
      carSprite[3].setPosition(170, 64);
      carYSpeed[3] = -5;
    }
    catch (IOException e) {
      System.err.println("Failed loading images!");
    }

    // 设置音乐为WAV格式播放
    try {
      InputStream is = getClass().getResourceAsStream("Music.mid");
      musicPlayer = Manager.createPlayer(is, "audio/midi");
      musicPlayer.prefetch();
      is = getClass().getResourceAsStream("Celebrate.wav");
      celebratePlayer = Manager.createPlayer(is, "audio/X-wav");
      celebratePlayer.prefetch();
      is = getClass().getResourceAsStream("Squish.wav");
      squishPlayer = Manager.createPlayer(is, "audio/X-wav");
      squishPlayer.prefetch();
      is = getClass().getResourceAsStream("GameOver.wav");
      gameoverPlayer = Manager.createPlayer(is, "audio/X-wav");
      gameoverPlayer.prefetch();
    }
    catch (IOException ioe) {
    }
    catch (MediaException me) {
    }

    // 开始音乐播放的条件
    try {
      musicPlayer.setLoopCount(-1);
      musicPlayer.start();
    }
    catch (MediaException me) {
    }

    // 启动动画线程
    sleeping = false;
    Thread t = new Thread(this);
    t.start();
  }
  
  public void stop() {
    // 关闭音乐播放器
    musicPlayer.close();
    celebratePlayer.close();
    squishPlayer.close();
    gameoverPlayer.close();

    // 停止动画
    sleeping = true;
  }
  
  public void run() {
    Graphics g = getGraphics();
    
    // 主游戏循环
    while (!sleeping) {
      update();
      draw(g);
      try {
        Thread.sleep(frameDelay);
      }
      catch (InterruptedException ie) {}
    }
  }

  private void update() {
    // 游戏是否重新开始
    if (gameOver) {
      int keyState = getKeyStates();
      if ((keyState & FIRE_PRESSED) != 0) {
        //重新开始
        try {
          musicPlayer.setMediaTime(0);
          musicPlayer.start();
        }
        catch (MediaException me) {
        }
        chickenSprite.setPosition(2, 77);
        gameOver = false;
        score = 0;
        numLives = 3;
      }

      // 游戏结束，不要任何更新
      return;
    }

    // 使用者移动小鸡
    if (++inputDelay > 2) {
      int keyState = getKeyStates();
      if ((keyState & LEFT_PRESSED) != 0) {
        chickenSprite.move(-6, 0);
        chickenSprite.nextFrame();
      }
      else if ((keyState & RIGHT_PRESSED) != 0) {
        chickenSprite.move(6, 0);
        chickenSprite.nextFrame();
      }
      if ((keyState & UP_PRESSED) != 0) {
        chickenSprite.move(0, -6);
        chickenSprite.nextFrame();
      }
      else if ((keyState & DOWN_PRESSED) != 0) {
        chickenSprite.move(0, 6);
        chickenSprite.nextFrame();
      }
      checkBounds(chickenSprite, false);

      // 重新设置输入延迟
      inputDelay = 0;
    }

    // 小鸡是否通过
    if (chickenSprite.getX() >200) {
      // 安全通过后的声音
      try {
        celebratePlayer.start();
      }
      catch (MediaException me) {
      }

      // 重新设定小鸡位置
      chickenSprite.setPosition(2, 77);
      score += 25;
    }

    // 更新小车的速度
    for (int i = 0; i < 4; i++) {
      // Move the car sprites
      carSprite[i].move(0, carYSpeed[i]);
      checkBounds(carSprite[i], true);

      // 检查为小鸡和汽车之间的碰撞
      if (chickenSprite.collidesWith(carSprite[i], true)) {
        // 小鸡死后的声音
        try {
          squishPlayer.start();
        }
        catch (MediaException me) {
        }

        // 游戏结束
        if (--numLives == 0) {
          // 停止游戏和播放声音
          try {
            musicPlayer.stop();
            gameoverPlayer.start();
          }
          catch (MediaException me) {
          }

          gameOver = true;
        } else {
          //重新设置小鸡位置
          chickenSprite.setPosition(2, 77);
        }

        // 停止更新
        break;
      }
    }
  }

  private void draw(Graphics g) {
    // 绘制公路背景
    g.drawImage(background, 0, 0, Graphics.TOP | Graphics.LEFT);
    
    // 设置小鸡的新位置
    for (int i = 0; i < numLives; i++)
      g.drawImage(chickenHead, 180 - ((i + 1) * 8), 190, Graphics.TOP | Graphics.LEFT);

    // 画小鸡精灵
    chickenSprite.paint(g);

    //画小车精灵
    for (int i = 0; i < 4; i++)
      carSprite[i].paint(g);
    
    if (gameOver) {
      // 画游戏结束是所得分数
      g.setColor(255, 255, 255); // white
      g.setFont(Font.getFont(Font.FACE_MONOSPACE, Font.STYLE_BOLD, Font.SIZE_LARGE));
      g.drawString("游戏终结", 90, 40, Graphics.TOP | Graphics.HCENTER);
      g.setFont(Font.getFont(Font.FACE_MONOSPACE, Font.STYLE_BOLD, Font.SIZE_MEDIUM));
      g.drawString("你的成绩是： " + score + " 分", 90, 70, Graphics.TOP |
        Graphics.HCENTER);
    }

    flushGraphics();
  }

  private void checkBounds(Sprite sprite, boolean wrap) {
    // 如果有需要的话停止精灵
    if (wrap) {
      // 画一个精灵在边框位置
      if (sprite.getX() < -sprite.getWidth())
        sprite.setPosition(getWidth(), sprite.getY());
      else if (sprite.getX() > getWidth())
        sprite.setPosition(-sprite.getWidth(), sprite.getY());
      if (sprite.getY() < -sprite.getHeight())
        sprite.setPosition(sprite.getX(), getHeight());
      else if (sprite.getY() > getHeight())
        sprite.setPosition(sprite.getX(), -sprite.getHeight());
    }
    else {
      // 停止精灵在边框位置
      if (sprite.getX() < 0)
        sprite.setPosition(0, sprite.getY());
      else if (sprite.getX() > (getWidth() - sprite.getWidth()))
        sprite.setPosition(getWidth() - sprite.getWidth(), sprite.getY());
      if (sprite.getY() < 0)
        sprite.setPosition(sprite.getX(), 0);
      else if (sprite.getY() > (getHeight() - sprite.getHeight()))
        sprite.setPosition(sprite.getX(), getHeight() - sprite.getHeight());
    }
  }
}