Android 项目贪吃蛇最初版本实现。

1. DesktopView.java是地图文件，用来画出桌面的文件
2. Food.java食物类文件 
3. Rock.java石头类文件 
4. Snake.java蛇类文件 
5. SnakeActivity.java主要Activity 
6. SnakeView.java画出蛇的文件

代码如下

package mars.com;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.WindowManager;

public class SnakeActivity extends Activity {
  public static final int CELL = 20;// 一个方格像素为20
  public static WindowManager windowManager;
  public static int SCREEN_WIDTH;// 屏幕宽度
  public static int SCREEN_HEIGHT;// 屏幕高度
  public static int NUMBER;// 横向个数

  SnakeView snakeView;
  Snake snake;
  Food food;
  Rock rock;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    this.initVars();
    snake = new Snake();
    food = new Food();
    rock = new Rock();
    snakeView = new SnakeView(getApplicationContext(), snake, food, rock);
    snakeView.setFocusable(true);
    setContentView(snakeView);
    snake.start();
  }

  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
    case KeyEvent.KEYCODE_BACK:
      finish();
      System.exit(0);
      break;
    }
    return super.onKeyDown(keyCode, event);
  }

  private void initVars() {
    windowManager = SnakeActivity.this.getWindowManager();
    SCREEN_HEIGHT = windowManager.getDefaultDisplay().getHeight();
    SCREEN_WIDTH = windowManager.getDefaultDisplay().getWidth();
    NUMBER = SCREEN_WIDTH / CELL;
  }
}

Snake类文件

package mars.com;

import java.util.ArrayList;
import java.util.LinkedList;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Point;

public class Snake {
  // 方向按钮
  public static final int UP = 1;
  public static final int DOWN = -1;
  public static final int LEFT = -2;
  public static final int RIGHT = 2;
  public static int oldDirection = RIGHT;
  public static int newDirection = RIGHT;
  public static LinkedList snakeBody = new LinkedList();
  private Point snakeTail;
  private boolean LIFE = true;

  public Snake() {
    int x = SnakeActivity.NUMBER / 2;
    int y = SnakeActivity.NUMBER / 2;
    for (int i = 0; i < 3; i++) {
      snakeBody.add(new Point(x--, y));
    }
  }

  public int getSpeed() {
    return -20 * snakeBody.size();// 返回的是负的时间，身体越长，剩余的时间越短，运动越快
  }

  public void eatRock(Rock rock) {
    ArrayList rocks = rock.getRocks();
    for (int i = 0; i < 3; i++) {
      if (snakeBody.getFirst().equals(rocks.get(i))) {
        LIFE = false;
        break;
      }
    }
  }

  public void eatWall() {
    if (snakeBody.getFirst().x < 0 || snakeBody.getFirst().y < 0
        || snakeBody.getFirst().x == SnakeActivity.NUMBER
        || snakeBody.getFirst().y == SnakeActivity.NUMBER) {
      LIFE = false;
    }
  }

  public void eatFood(Food food, Rock rock) {
    if (snakeBody.getFirst().equals(food.eatFood())) {
      snakeBody.addLast(snakeTail);
      food.createFood();
      rock.createRocks();
    }
  }

  public void eatHimself() {
    for (int i = 1; i < snakeBody.size(); i++) {
      if (snakeBody.get(i).equals(snakeBody.getFirst())) {
        LIFE = false;
        break;
      }
    }
  }

  public void move() {
    snakeTail = snakeBody.getLast();
    Point headPoint = snakeBody.getFirst();
    Point point = new Point();
    // 如果新方向和老方向在一条直线上
    if (oldDirection == newDirection || oldDirection + newDirection == 0) {
      if (oldDirection == UP) {
        point.set(headPoint.x, headPoint.y - 1);
      } else if (oldDirection == DOWN) {
        point.set(headPoint.x, headPoint.y + 1);
      } else if (oldDirection == LEFT) {
        point.set(headPoint.x - 1, headPoint.y);
      } else if (oldDirection == RIGHT) {
        point.set(headPoint.x + 1, headPoint.y);
      }
      snakeBody.addFirst(point);
      snakeBody.removeLast();
      return;
    }
    // 如果没有在一条直线上,进行拐弯
    switch (newDirection) {
    case UP:
      point.set(headPoint.x, headPoint.y - 1);
      break;
    case DOWN:
      point.set(headPoint.x, headPoint.y + 1);
      break;
    case LEFT:
      point.set(headPoint.x - 1, headPoint.y);
      break;
    case RIGHT:
      point.set(headPoint.x + 1, headPoint.y);
      break;
    }
    oldDirection = newDirection;
    snakeBody.addFirst(point);
    snakeBody.removeLast();
  }

  class Tsnake implements Runnable {
    public void run() {
      while (LIFE) {
        move();
        try {
          Thread.sleep(500 + getSpeed());
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
    }
  }

  public void start() {
    new Thread(new Tsnake()).start();
  }

  public void display(Canvas canvas, Context context) {
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    paint.setStyle(Style.FILL);
    for (int i = 0; i < snakeBody.size(); i++) {
      int x = snakeBody.get(i).x * SnakeActivity.CELL;
      int y = snakeBody.get(i).y * SnakeActivity.CELL;
      canvas.drawRect(x, y, x + SnakeActivity.CELL, y
          + SnakeActivity.CELL, paint);
    }
    paint.setColor(Color.RED);
    if (LIFE == false) {
      Bitmap image = BitmapFactory.decodeStream(context.getResources()
          .openRawResource(R.drawable.fail));
      canvas.drawBitmap(image, 200, 200, paint);
    }
  }
}

SnakeView类文件

package mars.com;

import android.content.Context;
import android.graphics.Canvas;

public class SnakeView extends DesktopView {
  private Snake snake;
  private Food food;
  private Rock rock;
  private Context context;

  public SnakeView(Context context, Snake snake, Food food, Rock rock) {
    super(context);
    this.snake = snake;
    this.food = food;
    this.rock = rock;
    this.context = context;
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    snake.display(canvas, context);
    food.display(canvas);
    rock.display(canvas);
    snake.eatFood(food, rock);
    snake.eatRock(rock);
    snake.eatHimself();
    snake.eatWall();
  }
}

石头类文件

package mars.com;

import java.util.ArrayList;
import java.util.Random;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Point;

public class Rock {
  public static ArrayList rocks = new ArrayList();
  public int OK = 0;
  private Point p;

  public Rock() {
    init();
  }

  public void init() {
    rocks = new ArrayList();
    for (int i = 0; i < 3; i++) {
      p = new Point();
      p.x = new Random().nextInt(SnakeActivity.NUMBER);
      p.y = new Random().nextInt(SnakeActivity.NUMBER);
      if (rocks.contains(p) == true
          || Snake.snakeBody.contains(p) == true) {
        i--;
      } else {
        rocks.add(p);
      }
    }
  }

  public void createRocks() {
    init();
  }

  public ArrayList getRocks() {
    return rocks;
  }

  public void display(Canvas canvas) {
    Paint paint = new Paint();
    paint.setColor(Color.RED);
    paint.setStyle(Style.FILL);
    for (int i = 0; i < 3; i++) {
      int x = rocks.get(i).x * SnakeActivity.CELL;
      int y = rocks.get(i).y * SnakeActivity.CELL;
      canvas.drawRect(x, y, x + SnakeActivity.CELL, y
          + SnakeActivity.CELL, paint);
    }

  }
}

Food类文件

package mars.com;

import java.util.Random;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Point;

public class Food {
  private Point p = new Point();

  public Food() {
    init();
  }

  public Point eatFood() {
    return p;
  }

  public void init() {
    while (true) {
      p.x = new Random().nextInt(SnakeActivity.NUMBER);
      p.y = new Random().nextInt(SnakeActivity.NUMBER);
      if (Snake.snakeBody.contains(p) == false) {// 如果不包含就跳出循环
        break;
      }
    }
  }

  public void createFood() {
    init();
  }

  public void display(Canvas canvas) {
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    paint.setStyle(Style.FILL);
    canvas.drawRect(p.x * SnakeActivity.CELL, p.y * SnakeActivity.CELL,
        (p.x + 1) * SnakeActivity.CELL, (p.y + 1) * SnakeActivity.CELL,
        paint);
  }
}

桌面类文件

package mars.com;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.View;

public class DesktopView extends View {

  private int width;
  private int height;

  public DesktopView(Context context) {
    super(context);
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawColor(Color.WHITE);// 为画布设置颜色
    canvas.setViewport(SnakeActivity.SCREEN_WIDTH,
        SnakeActivity.SCREEN_WIDTH);
    Paint paint = new Paint();
    paint.setColor(Color.BLUE);
    // 画横线
    for (int i = 0; i <= SnakeActivity.NUMBER; i++)
      canvas.drawLine(i * SnakeActivity.CELL, 0, i * SnakeActivity.CELL,
          SnakeActivity.CELL * SnakeActivity.NUMBER, paint);
    // 画竖线
    for (int i = 0; i <= SnakeActivity.NUMBER; i++)
      canvas.drawLine(0, i * SnakeActivity.CELL, SnakeActivity.CELL
          * SnakeActivity.NUMBER, i * SnakeActivity.CELL, paint);
    // 开始画按钮
    paint.setColor(Color.GRAY);
    int x = 0;
    int y = SnakeActivity.SCREEN_WIDTH;
    width = SnakeActivity.SCREEN_WIDTH / 7;
    height = (SnakeActivity.SCREEN_HEIGHT - SnakeActivity.SCREEN_WIDTH) / 5;
    Bitmap image = BitmapFactory.decodeStream(getResources()
        .openRawResource(R.drawable.left));
    canvas.drawBitmap(image, x + width * 3, y + height * 2, paint);
    image = BitmapFactory.decodeStream(getResources().openRawResource(
        R.drawable.right));
    canvas.drawBitmap(image, x + width * 5, y + height * 2, paint);
    image = BitmapFactory.decodeStream(getResources().openRawResource(
        R.drawable.up));
    canvas.drawBitmap(image, x + width * 4, y + height * 1, paint);
    image = BitmapFactory.decodeStream(getResources().openRawResource(
        R.drawable.down));
    canvas.drawBitmap(image, x + width * 4, y + height * 3, paint);
    postInvalidate();// 更新页面
  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();
    Bitmap image = BitmapFactory.decodeStream(getResources()
        .openRawResource(R.drawable.left));
    int imageX = image.getWidth();
    int imageY = image.getHeight();
    // 如果按向上键
    if (x > 4 * width && x < 4 * width + imageX
        && y > height + SnakeActivity.SCREEN_WIDTH
        && y < imageY + height + SnakeActivity.SCREEN_WIDTH) {
      System.out.println("***上");
      Snake.newDirection = Snake.UP;
    }
    // 如果是向下键
    if (x > 4 * width && x < 4 * width + imageX
        && y > 3 * height + SnakeActivity.SCREEN_WIDTH
        && y < imageY + 3 * height + SnakeActivity.SCREEN_WIDTH) {
      System.out.println("***下");
      Snake.newDirection = Snake.DOWN;
    }
    // 如果是左键
    if (x > 3 * width && x < 3 * width + imageX
        && y > 2 * height + SnakeActivity.SCREEN_WIDTH
        && y < imageY + 2 * height + SnakeActivity.SCREEN_WIDTH) {
      System.out.println("***左");
      Snake.newDirection = Snake.LEFT;
    }
    // 如果是右键
    if (x > 5 * width && x < 5 * width + imageX
        && y > 2 * height + SnakeActivity.SCREEN_WIDTH
        && y < imageY + 2 * height + SnakeActivity.SCREEN_WIDTH) {
      System.out.println("***右");
      Snake.newDirection = Snake.RIGHT;
    }

    return super.onTouchEvent(event);
  }
}

项目问题：Snake主Activity启动加载layout布局，然后对SnakeView进行初始化，项目启动，主界面显示 “press up to start game”，这个时候我如何操作都不能启动项目，因为这个游戏试运行在带手柄的游戏设备上的，手机是无法启动它的，使用模拟器可以进行适当的设置调出前后左右操作键。后期会修改这个项目使其能够通过滑动去操作游戏。