Android實戰打飛機游戲之無限循環的背景圖(2)

首先分析下游戲界面內的元素：
無限滾動的背景圖, 可以操作的主角,主角的子彈, 主角的血量,兩種怪物(敵機),一個boss, boss的爆炸效果.

先看效果圖

1、首先實現無限滾動的背景圖 原理: 定義兩個位圖對象 當第一個位圖到末尾是 第二個位圖從第一個位圖的末尾跟上.

public class GameBg {
 // 游戲背景的圖片資源
 // 為了循環播放，這裡定義兩個位圖對象，
 // 其資源引用的是同一張圖片
 private Bitmap bmpBackGround1;
 private Bitmap bmpBackGround2;

 // 游戲背景坐標
 private int bg1x, bg1y, bg2x, bg2y;

 private int speed = 3;

 public GameBg(Bitmap bmpBackGround) {
  this.bmpBackGround1 = bmpBackGround;
  this.bmpBackGround2 = bmpBackGround;
  // 首先讓第一張填滿屏幕
  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;
  }
 }

}

然後再在MySurfaceview裡面調用方法

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

 // 1 定義游戲狀態常量
 public static final int GAME_MENU = 0;// 游戲菜單
 public static final int GAMEING = 1;// 游戲中
 public static final int GAME_WIN = 2;// 游戲勝利
 public static final int GAME_LOST = 3;// 游戲失敗
 public static final int GAME_PAUSE = -1;// 游戲菜單
 // 當前游戲狀態(默認初始在游戲菜單界面)
 public static int gameState = GAME_MENU;
 // 聲明一個Resources實例便於加載圖片
 private Resources res = this.getResources();
 // 聲明游戲需要用到的圖片資源(圖片聲明)
 private Bitmap bmpBackGround;// 游戲背景
 private Bitmap bmpBoom;// 爆炸效果
 private Bitmap bmpBoosBoom;// Boos爆炸效果
 private Bitmap bmpButton;// 游戲開始按鈕
 private Bitmap bmpButtonPress;// 游戲開始按鈕被點擊
 private Bitmap bmpEnemyDuck;// 怪物鴨子
 private Bitmap bmpEnemyFly;// 怪物蒼蠅
 private Bitmap bmpEnemyBoos;// 怪物豬頭Boos
 private Bitmap bmpGameWin;// 游戲勝利背景
 private Bitmap bmpGameLost;// 游戲失敗背景
 private Bitmap bmpPlayer;// 游戲主角飛機
 private Bitmap bmpPlayerHp;// 主角飛機血量
 private Bitmap bmpMenu;// 菜單背景
 public static Bitmap bmpBullet;// 子彈
 public static Bitmap bmpEnemyBullet;// 敵機子彈
 public static Bitmap bmpBossBullet;// Boss子彈
 public static int screenW;
 public static int screenH;

 //
 private GameMenu gameMenu;
 private GameBg gameBg;

 /**
  * SurfaceView初始化函數
  */
 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視圖創建，響應此函數
  */
 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  screenW = this.getWidth();
  screenH = this.getHeight();
  initGame();
  flag = true;
  // 實例線程
  th = new Thread(this);
  // 啟動線程
  th.start();
 }

 /**
  * 加載游戲資源
  */
 private void initGame() {
  // 加載游戲資源
  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);

  //菜單類實例化
  gameMenu = new GameMenu(bmpMenu, bmpButton, bmpButtonPress);

  gameBg = new GameBg(bmpBackGround);

 }

 /**
  * 游戲繪圖
  */
 public void myDraw() {
  try {
   canvas = sfh.lockCanvas();
   if (canvas != null) {
    canvas.drawColor(Color.WHITE);
    // 繪圖函數根據游戲狀態不同進行不同繪制

    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);
  }
 }

 /**
  * 觸屏事件監聽
  */
 @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;
 }

 /**
  * 按鍵事件監聽
  */
 @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);
 }

 /**
  * 游戲邏輯
  */
 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視圖狀態發生改變，響應此函數
  */
 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width,
   int height) {
 }

 /**
  * SurfaceView視圖消亡時，響應此函數
  */
 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  flag = false;
 }
}

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