java中image显示图片，随上下左右键移动

 1 import java.awt.*;
 2 import java.awt.event.*;
 3 
 4 class FTest {
 5   public static void main(String[] args){
 6      final MyFrame form = new MyFrame();
 7     // form.setBounds(100, 100, 500, 500);
 8      
 9      form.setMyFullScreen();
10      form.addWindowListener(new Wclose());
11      form.addKeyListener(new KeyAdapter(){
12         public void keyPressed(KeyEvent e){
13             
14             form.w=form.getWidth();//获取当前窗口的大小
15             form.h=form.getHeight();
16             if(e.getKeyCode()==KeyEvent.VK_DOWN){
17                 if(form.p.y < form.h-form.imH){
18                     form.repaint(form.p.x,form.p.y,form.imW, form.StepLength);
19                     form.p.y=form.p.y+form.StepLength;
20                     
21                 }
22             }
23             else if(e.getKeyCode()==KeyEvent.VK_UP){
24                 if(form.p.y>form.getX()){
25                     form.repaint(form.p.x,form.p.y+form.imH-form.StepLength,form.imW, form.StepLength);
26                     form.p.y-=form.StepLength;
27                 }
28             }
29             else if(e.getKeyCode()==KeyEvent.VK_LEFT){
30                 if(form.p.x>form.getY()){
31                     form.repaint(form.p.x+form.imW-form.StepLength,form.p.y,form.StepLength, form.imH);
32                     form.p.x-=form.StepLength;
33                 }
34             }
35             else if(e.getKeyCode()==KeyEvent.VK_RIGHT){
36                 if(form.p.x<form.w-form.imW){
37                     form.repaint(form.p.x,form.p.y,form.StepLength, form.imH);
38                     form.p.x+=form.StepLength;
39                 }
40             }
41             form.paint(form.getGraphics());//重绘，调用的是重写的paint
42         }
43     });
44      form.setVisible(true);
45   }
46 }
47 
48 class MyFrame extends Frame {
49   Image mImages;//定义了两张图片对象
50   Image mImages2;
51   int StepLength=10;
52   int imH=100;//图像的大小
53   int imW=100;
54   int h=300;//当前的窗口的大小
55   int w=400;
56   Point p=new Point(20,20);//用来记录图像左上方定点的位置
57  // Point pF=new Point(0,0);
58   MyFrame(){
59     setSize(h,w);
60     
61     mImages = getToolkit().getImage("ap1.jpg");//创建图片对象
62     mImages2 = getToolkit().getImage("ap2.jpg");
63     
64     //java加载图象是异步的。也就是说，在你执行到getwidth时，它还不一定读完图象。所以当然是-1了。 
65     //可以用下面的程序等待加载 
66     MediaTracker   media   =   new   MediaTracker(this); 
67     media.addImage(mImages2,1); 
68     try{media.waitForID(1);}
69     catch(InterruptedException e){
70     }
71     //如果没有上面这段程序，imH,和imW就会是-1
72     imH=mImages2.getHeight(null);
73     imW=mImages2.getWidth(null);
74   }
75   public void paint(Graphics g){
76     g.drawImage(mImages2,p.x,p.y,imW,imH,this);
77   }
78   
79   public void setMyFullScreen(){
80       //把当前frame设置成全屏
81       Dimension   screenSize=this.getToolkit().getScreenSize(); 
82       this.setSize(screenSize.width,screenSize.height); 
83       this.setUndecorated(true); 
84       this.setExtendedState(Frame.MAXIMIZED_BOTH);
85   }
86 }
87 
88 class Wclose extends WindowAdapter {
89     public void windowClosing(WindowEvent e) {
90     System.exit(0);
91     }
92 }