UML软件工程组织

贪吃蛇Java源码分析
mccxj 的 Blog
/**************************************************************************
*文件名:GreedSnake.java
*作者:C.Jason
*要点分析:
*1)主要部分已经集成为一个对象SnakeModel,利用键盘控制实现操作。
*************************************************************************/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
//=============================================
//Main Class
//=============================================
public class GreedSnake implements KeyListener
{
JFrame mainFrame;
Canvas paintCanvas;
JLabel labelScore;//计分牌
SnakeModel snakeModel=null;// 蛇
public static final int canvasWidth=200;
public static final int canvasHeight=300;
public static final int nodeWidth=10;
public static final int nodeHeight=10;
//----------------------------------------------------------------------
//GreedSnake():初始化游戏界面
//----------------------------------------------------------------------
public GreedSnake()
{
//设置界面元素
mainFrame=new JFrame("GreedSnake");
Container cp=mainFrame.getContentPane();
labelScore=new JLabel("Score:");
cp.add(labelScore,BorderLayout.NORTH);
paintCanvas=new Canvas();
paintCanvas.setSize(canvasWidth+1,canvasHeight+1);
paintCanvas.addKeyListener(this);
cp.add(paintCanvas,BorderLayout.CENTER);
JPanel panelButtom=new JPanel();
panelButtom.setLayout(new BorderLayout());
JLabel labelHelp;// 帮助信息
labelHelp=new JLabel("PageUp, PageDown for speed;",JLabel.CENTER);
panelButtom.add(labelHelp,BorderLayout.NORTH);
labelHelp=new JLabel("ENTER or R or S for start;",JLabel.CENTER);
panelButtom.add(labelHelp,BorderLayout.CENTER);
labelHelp=new JLabel("SPACE or P for pause",JLabel.CENTER);
panelButtom.add(labelHelp,BorderLayout.SOUTH);
cp.add(panelButtom,BorderLayout.SOUTH);
mainFrame.addKeyListener(this);
mainFrame.pack();
mainFrame.setResizable(false);
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.setVisible(true);
begin();
}
//----------------------------------------------------------------------
//keyPressed():按键检测
//----------------------------------------------------------------------
public void keyPressed(KeyEvent e)
{
int keyCode=e.getKeyCode();
if(snakeModel.running) switch(keyCode)
{
case KeyEvent.VK_UP:
snakeModel.changeDirection(SnakeModel.UP);
break;
case KeyEvent.VK_DOWN:
snakeModel.changeDirection(SnakeModel.DOWN);
break;
case KeyEvent.VK_LEFT:
snakeModel.changeDirection(SnakeModel.LEFT);
break;
case KeyEvent.VK_RIGHT:
snakeModel.changeDirection(SnakeModel.RIGHT);
break;
case KeyEvent.VK_ADD:
case KeyEvent.VK_PAGE_UP:
snakeModel.speedUp();// 加速
break;
case KeyEvent.VK_SUBTRACT:
case KeyEvent.VK_PAGE_DOWN:
snakeModel.speedDown();// 减速
break;
case KeyEvent.VK_SPACE:
case KeyEvent.VK_P:
snakeModel.changePauseState();// 暂停或继续
break;
default:
}
//重新开始
if(keyCode==KeyEvent.VK_R || keyCode==KeyEvent.VK_S
|| keyCode==KeyEvent.VK_ENTER)
{
snakeModel.running=false;
begin();
}
}
//----------------------------------------------------------------------
//keyReleased():空函数
//----------------------------------------------------------------------
public void keyReleased(KeyEvent e)
{
}
//----------------------------------------------------------------------
//keyTyped():空函数
//----------------------------------------------------------------------
public void keyTyped(KeyEvent e)
{
}
//----------------------------------------------------------------------
//repaint():绘制游戏界面(包括蛇和食物)
//----------------------------------------------------------------------
void repaint()
{
Graphics g=paintCanvas.getGraphics();
//draw background
g.setColor(Color.WHITE);
g.fillRect(0,0,canvasWidth,canvasHeight);
//draw the snake
g.setColor(Color.BLACK);
LinkedList na=snakeModel.nodeArray;
Iterator it=na.iterator();
while(it.hasNext())
{
Node n=(Node)it.next();
drawNode(g,n);
}
// draw the food
g.setColor(Color.RED);
Node n=snakeModel.food;
drawNode(g,n);
updateScore();
}
//----------------------------------------------------------------------
//drawNode():绘画某一结点(蛇身或食物)
//----------------------------------------------------------------------
private void drawNode(Graphics g,Node n)
{
g.fillRect(n.x*nodeWidth,n.y*nodeHeight,nodeWidth-1,nodeHeight-1);
}
//----------------------------------------------------------------------
//updateScore():改变计分牌
//----------------------------------------------------------------------
public void updateScore()
{
String s="Score: "+snakeModel.score;
labelScore.setText(s);
}
//----------------------------------------------------------------------
//begin():游戏开始,放置贪吃蛇
//----------------------------------------------------------------------
void begin()
{
if(snakeModel==null||!snakeModel.running)
{
snakeModel=new SnakeModel(this,canvasWidth/nodeWidth,
this.canvasHeight/nodeHeight);
(new Thread(snakeModel)).start();
}
}
//----------------------------------------------------------------------
//main():主函数
//----------------------------------------------------------------------
public static void main(String[] args)
{
GreedSnake gs=new GreedSnake();
}
}
/**************************************************************************
*文件名:SnakeModel.java
*作者:C.Jason
*要点分析:
*1)数据结构:matrix[][]用来存储地图上面的信息,如果什么也没有设置为false,
* 如果有食物或蛇,设置为true;nodeArray,一个LinkedList,用来保存蛇的每
* 一节;food用来保存食物的位置;而Node类是保存每个位置的信息。
*2)重要函数:
* changeDirection(int newDirection) ,用来改变蛇前进的方向,而且只是
* 保存头部的前进方向,因为其他的前进方向已经用位置来指明了。 其中newDirection
* 必须和原来的direction不是相反方向,所以相反方向的值用了同样的奇偶性。在测试
* 的时候使用了direction%2!=newDirection%2 进行判断。
* moveOn(),用来更新蛇的位置,对于当前方向,把头部位置进行相应改变。如果越界,
* 结束;否则,检测是否遇到食物(加头部)或身体(结束);如果什么都没有,加上头部,
* 去掉尾部。由于用了LinkedList数据结构,省去了相当多的麻烦。
*************************************************************************/
import java.util.*;
import javax.swing.*;
//----------------------------------------------------------------------
//Node:结点类
//----------------------------------------------------------------------
class Node
{
int x;
int y;
Node(int x,int y)
{
this.x=x;
this.y=y;
}
}
//----------------------------------------------------------------------
//SnakeModel:贪吃蛇模型
//----------------------------------------------------------------------
class SnakeModel implements Runnable
{
GreedSnake gs;
boolean[][] matrix;// 界面数据保存在数组里
LinkedList nodeArray=new LinkedList();
Node food;
int maxX;//最大宽度
int maxY;//最大长度
int direction=2;//方向
boolean running=false;
int timeInterval=200;// 间隔时间(速度)
double speedChangeRate=0.75;// 速度改变程度
boolean paused=false;// 游戏状态
int score=0;
int countMove=0;
// UP和DOWN是偶数,RIGHT和LEFT是奇数
public static final int UP=2;
public static final int DOWN=4;
public static final int LEFT=1;
public static final int RIGHT=3;
//----------------------------------------------------------------------
//GreedModel():初始化界面
//----------------------------------------------------------------------
public SnakeModel(GreedSnake gs,int maxX,int maxY)
{
this.gs=gs;
this.maxX=maxX;
this.maxY=maxY;
matrix=new boolean[maxX][];
for(int i=0;i<maxX;++i)
{
matrix[i]=new boolean[maxY];
Arrays.fill(matrix[i],false);// 没有蛇和食物的地区置false
}
//初始化贪吃蛇
int initArrayLength=maxX>20 ? 10 : maxX/2;
for(int i=0;i<initArrayLength;++i)
{
int x=maxX/2+i;
int y=maxY/2;
nodeArray.addLast(new Node(x,y));
matrix[x][y]=true;// 蛇身处置true
}
food=createFood();
matrix[food.x][food.y]=true;// 食物处置true
}
//----------------------------------------------------------------------
//changeDirection():改变运动方向
//----------------------------------------------------------------------
public void changeDirection(int newDirection)
{
if(direction%2!=newDirection%2)// 避免冲突
{
direction=newDirection;
}
}
//----------------------------------------------------------------------
//moveOn():贪吃蛇运动函数
//----------------------------------------------------------------------
public boolean moveOn()
{
Node n=(Node)nodeArray.getFirst();
int x=n.x;
int y=n.y;
switch(direction)
{
case UP:
y--;
break;
case DOWN:
y++;
break;
case LEFT:
x--;
break;
case RIGHT:
x++;
break;
}
if((0<=x&&x<maxX)&&(0<=y&&y<maxY))
{
if(matrix[x][y])// 吃到食物或者撞到身体
{
if(x==food.x&&y==food.y)// 吃到食物
{
nodeArray.addFirst(food);// 在头部加上一结点
//计分规则与移动长度和速度有关
int scoreGet=(10000-200*countMove)/timeInterval;
score+=scoreGet>0 ? scoreGet : 10;
countMove=0;
food=createFood();
matrix[food.x][food.y]=true;
return true;
}
else return false;// 撞到身体
}
else//什么都没有碰到
{
nodeArray.addFirst(new Node(x,y));// 加上头部
matrix[x][y]=true;
n=(Node)nodeArray.removeLast();// 去掉尾部
matrix[n.x][n.y]=false;
countMove++;
return true;
}
}
return false;//越界(撞到墙壁)
}
//----------------------------------------------------------------------
//run():贪吃蛇运动线程
//----------------------------------------------------------------------
public void run()
{
running=true;
while(running)
{
try
{
Thread.sleep(timeInterval);
}catch(Exception e)
{
break;
}
if(!paused)
{
if(moveOn())// 未结束
{
gs.repaint();
}
else//游戏结束
{
JOptionPane.showMessageDialog(null,"GAME OVER",
"Game Over",JOptionPane.INFORMATION_MESSAGE);
break;
}
}
}
running=false;
}
//----------------------------------------------------------------------
//createFood():生成食物及放置地点
//----------------------------------------------------------------------
private Node createFood()
{
int x=0;
int y=0;
do
{
Random r=new Random();
x=r.nextInt(maxX);
y=r.nextInt(maxY);
}while(matrix[x][y]);
return new Node(x,y);
}
//----------------------------------------------------------------------
//speedUp():加快蛇运动速度
//----------------------------------------------------------------------
public void speedUp()
{
timeInterval*=speedChangeRate;
}
//----------------------------------------------------------------------
//speedDown():放慢蛇运动速度
//----------------------------------------------------------------------
public void speedDown()
{
timeInterval/=speedChangeRate;
}
//----------------------------------------------------------------------
//changePauseState(): 改变游戏状态(暂停或继续)
//----------------------------------------------------------------------
public void changePauseState()
{
paused=!paused;
}
}

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