enemy.java

一个用Java开发的射击类游戏

import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.Sprite;

public class Enemy extends Sprite
{
	private int	directStatus = 0;
	private int	currentFrame = 0;
	private int	lastDirectStatus = 0;

	//走步计数器
	private int	upNumber = 0;
	private int	downNumber = 0;
	private int	leftNumber = 0;
	private int	rightNumber = 0;

	//管理器
	private WallManager	wallManager = null;
	
	//走步受阻标志
	private boolean		isStopped = false;

	
	public Enemy(Image tempEnemyImage, WallManager tempWallManager)
	{
		super(tempEnemyImage, War.ENEMY_WIDTH, War.ENEMY_HEIGHT);
		wallManager = tempWallManager;
	}
	private void setDirectStatus(int tempDirectStatus)
	{
		directStatus = tempDirectStatus;
		lastDirectStatus = tempDirectStatus;
	}
	public int	getDirectStatus()
	{
		return directStatus;
	}
	public void move()
	{
		moveCompute();
		isStopped = false;
		if (directStatus == 0)
		{//上
			if (directStatus == lastDirectStatus)
			{
				currentFrame = (currentFrame+1)%3;
			}
			else
			{
				currentFrame = 0;
			}
			move(0, -War.ENEMY_MID_RATE);
			if (isLimited())
			{
				isStopped = true;
				move(0, War.ENEMY_MID_RATE);
			}
		}
		else if (directStatus == 1)
		{
			if (directStatus == lastDirectStatus)
			{
				currentFrame = 6 + (currentFrame - 6 + 1)%3;
			}
			else
			{
				currentFrame = 6;
			}
			move(0, War.ENEMY_MID_RATE);
			if (isLimited())
			{
				isStopped = true;
				move(0, -War.ENEMY_MID_RATE);
			}
		}
		else if (directStatus == 2)
		{
			if (directStatus == lastDirectStatus)
			{
				currentFrame = 9 + (currentFrame - 9 + 1)%3;
			}
			else
			{
				currentFrame = 9;
			}
			move(-War.ENEMY_MID_RATE, 0);
			if (isLimited())
			{
				isStopped = true;
				move(War.ENEMY_MID_RATE, 0);
			}
		}
		else
		{
			if (directStatus == lastDirectStatus)
			{
				currentFrame = 3 + (currentFrame - 3 + 1)%3;
			}
			else
			{
				currentFrame = 3;
			}
			move(War.ENEMY_MID_RATE, 0);
			if (isLimited())
			{
				isStopped = true;
				move(-War.ENEMY_MID_RATE, 0);
			}
		}
		setFrame(currentFrame);
	}
	private void moveCompute()
	{//每次使用setDirectStatus()后都要紧跟着使用return
		if (directStatus == 0)
		{//上
			upNumber++;
			if (isStopped)
			{
				setDirectStatus(3);
				return;
			}
		}
		else if (directStatus == 1)
		{
			downNumber++;
			if (isStopped)
			{
				setDirectStatus(2);
				return;
			}
			if (downNumber ==30)
			{
				downNumber = 0;
				setDirectStatus(3);
				return;
			}
		}
		else if (directStatus == 2)
		{
			leftNumber++;
			if (isStopped)
			{
				setDirectStatus(0);
				return;
			}
			setDirectStatus(3);
			return;
		}
		else
		{
			rightNumber++;
			if (isStopped)
			{
				setDirectStatus(1);
				return;
			}
			if (rightNumber ==30)
			{
				rightNumber = 0;
				setDirectStatus(1);
				return;
			}
		}
	}
	private boolean isLimited()
	{
		//受墙阻挡
		if (wallManager.collidesWith(this))
		{
			return true;
		}
		//受边界阻挡
		if (getX() < War.WAR_FIELD_LEFT || getX() > War.WAR_FIELD_LEFT + War.WAR_FIELD_WIDTH - War.ENEMY_WIDTH || getY() < War.WAR_FIELD_TOP || getY() > War.WAR_FIELD_TOP + War.WAR_FIELD_HEIGHT - War.ENEMY_HEIGHT)
		{//检查子弹是否超界
			return true;
		}
		return false;
	}
}