Android实战 * 游戏之无限循环的背景图(2)

首先分析下游戏界面内的元素：
无限滚动的背景图, 可以操作的主角,主角的 * , 主角的血量,两种怪物(敌机),一个boss, boss的 * 效果.

先看效果图

1、首先实现无限滚动的背景图 原理: 定义两个位图对象 当第一个位图到末尾是 第二个位图从第一个位图的末尾跟上.

public class GameBg {
// 游戏背景的图片资源
// 为了循环播放，这里定义两个位图对象，
// 其资源引用的是同一张图片
private Bitmap bmpBackGround1;
private Bitmap bmpBackGround2;

// 游戏背景坐标
private int bg1x, bg1y, bg2x, bg2y;

private int speed = 3;

public GameBg(Bitmap bmpBackGround) {
 this.bmpBackGround1 = bmpBackGround;
 this.bmpBackGround2 = bmpBackGround;
 // 首先让第一张填满屏幕
 bg1y = -Math.abs(bmpBackGround.getHeight() - MySurfaceView.screenH);

bg2y = bg1y - bmpBackGround1.getHeight() +50;
}

public void draw(Canvas canvas,Paint paint){

canvas.drawBitmap(bmpBackGround1, bg1x, bg1y, paint);
 canvas.drawBitmap(bmpBackGround2, bg2x, bg2y, paint);
}
public void logic(){
 bg1y +=speed;
 bg2y +=speed;

if(bg1y > MySurfaceView.screenH){
  bg1y = bg2y - bmpBackGround1.getHeight() +50;
 }
 if(bg2y > MySurfaceView.screenH){
  bg2y = bg1y - bmpBackGround1.getHeight() +50;
 }
}

}

然后再在MySurfaceview里面调用方法

public class MySurfaceView extends SurfaceView implements Callback, Runnable {
private SurfaceHolder sfh;
private Paint paint;
private Thread th;
private boolean flag;
private Canvas canvas;

// 1 定义游戏状态常量
public static final int GAME_MENU = 0;// 游戏菜单
public static final int GAMEING = 1;// 游戏中
public static final int GAME_WIN = 2;// 游戏胜利
public static final int GAME_LOST = 3;// 游戏失败
public static final int GAME_PAUSE = -1;// 游戏菜单
// 当前游戏状态(默认初始在游戏菜单界面)
public static int gameState = GAME_MENU;
// 声明一个Resources实例便于加载图片
private Resources res = this.getResources();
// 声明游戏需要用到的图片资源(图片声明)
private Bitmap bmpBackGround;// 游戏背景
private Bitmap bmpBoom;// * 效果
private Bitmap bmpBoosBoom;// Boos * 效果
private Bitmap bmpButton;// 游戏开始按钮
private Bitmap bmpButtonPress;// 游戏开始按钮被点击
private Bitmap bmpEnemyDuck;// 怪物鸭子
private Bitmap bmpEnemyFly;// 怪物苍蝇
private Bitmap bmpEnemyBoos;// 怪物猪头Boos
private Bitmap bmpGameWin;// 游戏胜利背景
private Bitmap bmpGameLost;// 游戏失败背景
private Bitmap bmpPlayer;// 游戏主角飞机
private Bitmap bmpPlayerHp;// 主角飞机血量
private Bitmap bmpMenu;// 菜单背景
public static Bitmap bmpBullet;// *
public static Bitmap bmpEnemyBullet;// 敌机 *
public static Bitmap bmpBossBullet;// Boss *
public static int screenW;
public static int screenH;

//
private GameMenu gameMenu;
private GameBg gameBg;

/**
 * SurfaceView初始化函数
 */
public MySurfaceView(Context context) {
 super(context);
 sfh = this.getHolder();
 sfh.addCallback(this);
 paint = new Paint();
 paint.setColor(Color.WHITE);
 paint.setAntiAlias(true);
 setFocusable(true);
}

/**
 * SurfaceView视图创建，响应此函数
 */
@Override
public void surfaceCreated(SurfaceHolder holder) {
 screenW = this.getWidth();
 screenH = this.getHeight();
 initGame();
 flag = true;
 // 实例线程
 th = new Thread(this);
 // 启动线程
 th.start();
}

/**
 * 加载游戏资源
 */
private void initGame() {
 // 加载游戏资源
 bmpBackGround = BitmapFactory
   .decodeResource(res, R.drawable.background);
 bmpBoom = BitmapFactory.decodeResource(res, R.drawable.boom);
 bmpBoosBoom = BitmapFactory.decodeResource(res, R.drawable.boos_boom);
 bmpButton = BitmapFactory.decodeResource(res, R.drawable.button);
 bmpButtonPress = BitmapFactory.decodeResource(res,
   R.drawable.button_press);
 bmpEnemyDuck = BitmapFactory.decodeResource(res, R.drawable.enemy_duck);
 bmpEnemyFly = BitmapFactory.decodeResource(res, R.drawable.enemy_fly);
 bmpEnemyBoos = BitmapFactory.decodeResource(res, R.drawable.enemy_pig);
 bmpGameWin = BitmapFactory.decodeResource(res, R.drawable.gamewin);
 bmpGameLost = BitmapFactory.decodeResource(res, R.drawable.gamelost);
 bmpPlayer = BitmapFactory.decodeResource(res, R.drawable.player);
 bmpPlayerHp = BitmapFactory.decodeResource(res, R.drawable.hp);
 bmpMenu = BitmapFactory.decodeResource(res, R.drawable.menu);
 bmpBullet = BitmapFactory.decodeResource(res, R.drawable.bullet);
 bmpEnemyBullet = BitmapFactory.decodeResource(res,
   R.drawable.bullet_enemy);
 bmpBossBullet = BitmapFactory
   .decodeResource(res, R.drawable.boosbullet);

//菜单类实例化
 gameMenu = new GameMenu(bmpMenu, bmpButton, bmpButtonPress);

gameBg = new GameBg(bmpBackGround);

}

/**
 * 游戏绘图
 */
public void myDraw() {
 try {
  canvas = sfh.lockCanvas();
  if (canvas != null) {
   canvas.drawColor(Color.WHITE);
   // 绘图函数根据游戏状态不同进行不同绘制

switch (gameState) {
   case GAME_MENU:

gameMenu.draw(canvas, paint);
    break;
   case GAMEING:
    gameBg.draw(canvas, paint);
    break;

case GAME_WIN:

break;
   case GAME_LOST:

break;
   case GAME_PAUSE:
    break;
   default:
    break;
   }

}
 } catch (Exception e) {
  // TODO: handle exception
 } finally {
  if (canvas != null)
   sfh.unlockCanvasAndPost(canvas);
 }
}

/**
 * 触屏事件监听
 */
@Override
public boolean onTouchEvent(MotionEvent event) {
 switch (gameState) {
 case GAME_MENU:

gameMenu.onTouchEvent(event);
  break;
 case GAMEING:
  break;

case GAME_WIN:

break;
 case GAME_LOST:

break;
 case GAME_PAUSE:

break;
 }
 return true;
}

/**
 * 按键事件监听
 */
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
 switch (gameState) {
 case GAME_MENU:

break;
 case GAMEING:
  break;

case GAME_WIN:

break;
 case GAME_LOST:

break;
 case GAME_PAUSE:
  break;
 }
 return super.onKeyDown(keyCode, event);
}

@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
 switch (gameState) {
 case GAME_MENU:

break;
 case GAMEING:
  break;

case GAME_WIN:

break;
 case GAME_LOST:

break;
 case GAME_PAUSE:
  break;
 }
 return super.onKeyUp(keyCode, event);
}

/**
 * 游戏逻辑
 */
private void logic() {
 switch (gameState) {
 case GAME_MENU:

break;
 case GAMEING:
  gameBg.logic();
  break;

case GAME_WIN:

break;
 case GAME_LOST:

break;
 case GAME_PAUSE:
  break;
 }

}

@Override
public void run() {
 while (flag) {
  long start = System.currentTimeMillis();
  myDraw();
  logic();
  long end = System.currentTimeMillis();
  try {
   if (end - start < 50) {
    Thread.sleep(50 - (end - start));
   }
  } catch (InterruptedException e) {
   e.printStackTrace();
  }
 }
}

/**
 * SurfaceView视图状态发生改变，响应此函数
 */
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
  int height) {
}

/**
 * SurfaceView视图消亡时，响应此函数
 */
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
 flag = false;
}
}