snakepart.java~31~

j2me源代码

package snake;

public class SnakePart {
  private int x;
  private int y;
  private byte dir;
  private int len;

  public SnakePart(int xPos, int yPos, byte direction, int length) {
    x = xPos;
    y = yPos;
    dir = direction;
    len = length;
  }

  /**
   * 段增加一个小方格
   */
  public void increase(){
    len++;
    switch (dir) {
      case Snake.DOWN:
        y++;
        break;
      case Snake.LEFT:
        x--;
        break;
      case Snake.RIGHT:
        x++;
        break;
      case Snake.UP:
        y--;
        break;
    }
  }

  /**
   * 段减少一个小方格
   */
  public void decrease(){
    len--;
  }

  /**
   * 测试点(x,y)是否在该段内，用于测试蛇头是否跟蛇身接触
   * @param x int
   * @param y int
   * @return boolean
   */
  public boolean isPtInPart(int x, int y){
    switch (dir) {
      case Snake.LEFT:
        return ( (y == this.y) && ( (x >= this.x) && (x <= getEndX())));
      case Snake.RIGHT:
        return ( (y == this.y) && ( (x <= this.x) && (x >= getEndX())));
      case Snake.UP:
        return ( (x == this.x) && ( (y >= this.y) && (y <= getEndY())));
      case Snake.DOWN:
        return ( (x == this.x) && ( (y <= this.y) && (y >= getEndY())));
    }
    return false;
  }

  /**
   * 返回段尾的Y坐标
   * @return int
   */
  public int getEndY() {
    if(dir == Snake.DOWN)
      return y-len+1;
    else if(dir == Snake.UP)
      return y+len-1;
    else
      return y;
  }

  /**
   * 返回段尾的X坐标
   * @return int
   */
  public int getEndX() {
    if(dir == Snake.LEFT)
      return x+len-1;
    else if(dir == Snake.RIGHT)
      return x-len+1;
    else
      return x;
  }

  /**
   * 返回段首的X坐标
   * @return int
   */
  public int getStartX(){
    return x;
  }

  /**
   * 返回段首的Y坐标
   * @return int
   */
  public int getStartY(){
    return y;
  }

  /**
   * 返回当前段的移动方向
   * @return byte
   */
  public byte getDirection(){
    return dir;
  }

  /**
   * 返回当前段的长度
   * @return int
   */
  public int getLength(){
    return len;
  }
}