core java 中的sketch小游戏

1. import javax.swing.*;
2. import java.awt.geom.*;
3. import java.util.*;
4. import java.awt.event.*;
5. import java.awt.*;
6. public class Sketch {
7.     public static void main(String []args){
8.         SketchFrame  sf=new SketchFrame();
9.         sf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
10.         sf.show();
11.     }
13. }
14. class SketchFrame  extends JFrame{
15.     public SketchFrame(){
16.         setTitle("phenix");
17.         setSize(this.DEFAULT_WIDTH,this.DEFAULT_HEIGHT);
18.         SketchPanel panel=new SketchPanel();
19.         Container  contentPane=getContentPane();
20.         contentPane.add(panel);
21.     }
22.     public static final int DEFAULT_WIDTH=300;
23.     public static final int DEFAULT_HEIGHT=400;
24. }
25. class SketchPanel  extends JPanel{
26.     private Point2D last;
27.     private ArrayList lines;
28.     private static final int SMALL_INCREMENT=1;
29.     private static final int LARGE_INCREMENT=5;
30.     public  SketchPanel(){
31.         last=new Point2D.Double(100,100);
32.         lines=new ArrayList();
33.         KeyHandler listener=new KeyHandler();
34.         addKeyListener(listener);
35.         setFocusable(true);
36.     }
37.     public void add(int dx,int dy){
38.         Point2D  end=new Point2D.Double(last.getX()+dx,last.getY()+dy);
39.         Line2D  line=new Line2D.Double(last,end);
40.         lines.add(line);
41.         repaint();
42.         last=end;
43.         System.out.println("哈哈");
44.     }
45.     public void paintComponent(Graphics g){
46.         super.paintComponent(g);
47.         Graphics2D g2=(Graphics2D)g;
48.         for(int i=0;i<lines.size();i++){
49.             g2.draw((Line2D)lines.get(i));
50.         }
51.     }
52.     private class KeyHandler implements KeyListener
53.     {
54.         
55.         public void keyPressed(KeyEvent event){
56.               int keyCode=event.getKeyCode();
57.               //set distance
58.               int d;
59.               if(event.isShiftDown()){
60.                   d=LARGE_INCREMENT;
61.                   System.out.println("shift key is down");
62.               }
63.               else
64.               {
65.                   d=SMALL_INCREMENT;
66.               }
67.               if(keyCode==KeyEvent.VK_LEFT){
68.                   add(-d,0);                  
69.               }
70.               else
71.                   if(keyCode==KeyEvent.VK_RIGHT){
72.                       add(d,0);
73.                   }
74.                   else
75.                       if(keyCode==KeyEvent.VK_UP){
76.                           add(0,-d);
77.                       }
78.                       else
79.                           if(keyCode==KeyEvent.VK_DOWN)
80.                           {
81.                               add(0,d);
82.                           }
83.         }
84.         public void keyReleased(KeyEvent event){
85.             
86.         }
87.         public void keyTyped(KeyEvent event){
88.             char keyChar=event.getKeyChar();
89.             int d;
90.             if(Character.isUpperCase(keyChar)){
91.                 d=LARGE_INCREMENT;
92.             }
93.             else{
94.                 d=SMALL_INCREMENT;
95.             }
96.             if(keyChar=='h'){
97.                 add(-d,0);
98.             }else
99.                 if(keyChar=='l'){add(d,0);}
100.                 else if(keyChar=='k')add(0,-d);
101.                 else if(keyChar=='j')add(0,d);
102.         }
103.     }
104. }