simpledrawer.java

java小游戏代码

// 程序：简单的绘图游戏
// 范例文件：SimpleDrawer.java

import java.awt.*;
import java.applet.*;
import java.awt.event.*;

public class SimpleDrawer extends Applet 
             implements MouseListener,MouseMotionListener
{
   int      AppletWidth,AppletHeight,drawX,drawY;
   Image    OffScreen;
   Cursor   drawCursor,eraseCursor;
   Graphics drawOffScreen;
      
   public void init()
   {
      addMouseListener(this);            //注册事件处理方法
      addMouseMotionListener(this);   

      setBackground(Color.white);        //设定背景为白色

      AppletWidth   = getSize().width;   //取得Applet的高度
      AppletHeight  = getSize().height;  //取得Applet的宽度

      drawCursor    = new Cursor(Cursor.CROSSHAIR_CURSOR);
      eraseCursor   = new Cursor(Cursor.HAND_CURSOR);

      //建立次画面
      OffScreen     = createImage(AppletWidth,AppletHeight);
      drawOffScreen = OffScreen.getGraphics();

      showStatus("请开始绘图...");
   }

   public void paint(Graphics g)
   {
      //将次画面贴到主画面中
      g.drawImage(OffScreen,0,0,this);
   }

   public void update(Graphics g)        //update()方法
   {
      paint(g);                          //只单纯调用paint()方法
   }
   
 //=====实现MouseListener界面=======================================
   public void mouseExited(MouseEvent e)      //鼠标离开Component
   {
      showStatus("绘图动作结束...");
   }

   public void mouseClicked(MouseEvent e)     //鼠标按键被按下后放开
   {
      //如果是右键产生的mouseClicked事件的话
      if((e.getModifiers() & InputEvent.BUTTON3_MASK) != 0)
      {
         //清除次画面
         drawOffScreen.setColor(getBackground());
         drawOffScreen.fillRect(0,0,AppletWidth,AppletHeight);
         drawOffScreen.setColor(getForeground());
         repaint();
      }   
   }

   public void mouseEntered(MouseEvent e)     //鼠标进入Component
   {
      setCursor(drawCursor);
      showStatus("请开始绘图...");
   }

   public void mousePressed(MouseEvent e)     //鼠标按键被按下
   {
      //如果是左键产生的mousePressed事件的话
      if((e.getModifiers() & InputEvent.BUTTON1_MASK) != 0)
      {
         //绘制一个宽度与高度各为1的实心矩形
         drawX = e.getX();
         drawY = e.getY();
         drawOffScreen.fillRect(drawX,drawY,1,1);
         repaint();
      }
   }

   public void mouseReleased(MouseEvent e)    //鼠标按键放开
   {
      showStatus("按下" + e.getClickCount() + "次");  
   }

   //=====实现MouseMotionListener界面=================================
   public void mouseMoved(MouseEvent e)       //鼠标移动时
   {
      if(e.isShiftDown())                     //如果配合按下shift键
      {
         setCursor(eraseCursor);        

         //此为橡皮擦的功能
         drawX = e.getX();
         drawY = e.getY();
         drawOffScreen.setColor(getBackground());
         drawOffScreen.fillRect(drawX - 5,drawY - 5,10,10);
         drawOffScreen.setColor(getForeground());
         repaint();
     }
     else
        setCursor(drawCursor);
   }  
 
   public void mouseDragged(MouseEvent e)     //鼠标拖曳时 
   {
      //如果是按下左键拖曳的话
      if((e.getModifiers() & InputEvent.BUTTON1_MASK) != 0)
      {
         //绘制粗线条
         drawOffScreen.fillRect(drawX-3,drawY-3,6,6);
         drawX = e.getX();
         drawY = e.getY();
         repaint();
      }
   }
}