额一个东西

publicclassOneBall {
publicstaticvoidmain(String[] args) {
BallJFramep=newBallJFrame();
}

importjava.awt.*;
publicclassBall {
intx;  //球的x坐标inty;  //球的y坐标Colorballcolor;  //球的颜色intd; //球的大小intdir; //有且仅有1， 2，3 ，4 四个固定的数值 1-左上，2-左下，3-右上，4-右下intspeed; //球的速度//定义球的四个运动方向（int  d）publicstaticfinalintLEFT_UP=1;
publicstaticfinalintLEFT_DOWN=2;
publicstaticfinalintRIGHT_UP=3;
publicstaticfinalintRIGHT_DOWN=4;
//使用构造方法完成小球的初始化设置（出厂设置）publicBall(){
this.x=100; //球的初始x坐标this.y=100; //球的初始y坐标this.d=50;  //球的初始直径this.dir=(int) (Math.random()*4)+1;   //球的初始方向    }
//行为//绘制球publicvoidpaintball(Graphicsg){
g.setColor(ballcolor);//球的颜色g.fillOval(x,y,d,d);//球的大小和位置    }
publicvoidballmove(){
intr=(int)(Math.random()*256);//球的颜色 r g bintg=(int)(Math.random()*256);
intb=(int)(Math.random()*256);
this.ballcolor=newColor(r,g,b);
//定义球在四个方向上的运动变化if (dir==RIGHT_UP){
x=x+speed;
y=y-speed;
        }
if(dir==RIGHT_DOWN){
x=x+speed;
y=y+speed;
        }
if (dir==LEFT_DOWN){
x=x-speed;
y=y+speed;
        }
if (dir==LEFT_UP){
x=x-speed;
y=y-speed;
        }
//以边为界限时，当遇见每条边的时候的运动方式//上if (y<=0){
//当球顺时针运动if (dir==RIGHT_UP)
dir=RIGHT_DOWN;
//当球逆时针运动if (dir==LEFT_UP)
dir=LEFT_DOWN;
        }
//下if (y>=500-d-30){
//顺时针if (dir==LEFT_DOWN)
dir=LEFT_UP;
//逆时针if (dir==RIGHT_DOWN)
dir=RIGHT_UP;
        }
//左if (x<=0) {
//顺时针if (dir==LEFT_UP)
dir=RIGHT_UP;
//逆时针if (dir==LEFT_DOWN)
dir=RIGHT_DOWN;
        }
//右if (x>=700-d-25){
//顺时针if (dir==RIGHT_DOWN){
dir=LEFT_DOWN;}
//逆时针if (dir==RIGHT_UP){
dir=LEFT_UP;}
        }
    }
}

importjavax.imageio.ImageIO;
importjavax.swing.*;
importjava.awt.image.BufferedImage;
importjava.io.File;
importjava.io.IOException;
publicclassBallJFrameextendsJFrame {
BufferedImageJFrameicon;
publicBallJFrame(){
try {
JFrameicon=ImageIO.read(newFile("start.png"));
        } catch (IOExceptione) {
e.printStackTrace();
        }
this.setIconImage(JFrameicon);  //设置窗口图标this.setTitle("小球弹弹弹");//设置窗口名称this.setSize(700,500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置窗口关闭进程结束//设置窗口大小不可改变this.setResizable(false);
//设置窗口初始位置居中this. setLocationRelativeTo(null);
BallJPanelballJPanel=newBallJPanel();
ballJPanel.move();
this.add(ballJPanel);
//设置窗口 - 显示/不显示this.setVisible(true);
    }
}

importjavax.swing.*;
importjava.awt.*;
publicclassBallJPanelextendsJPanel {
Ballball=newBall();
publicBallJPanel(){//构造方法，让画布的颜色是粉色pink色this.setBackground(Color.PINK);
    }
@Override//重构方法paint，一支笔。publicvoidpaint(Graphicsg) {
super.paint(g);
ball.paintball(g);
    }
publicvoidmove(){
//多线程，额我还白，我也不太懂。newThread(){
//1.球动publicvoidrun(){
while (true) {//写个死循环让你一直跑，哼。ball.ballmove();
try {
sleep(10);//休眠                    } catch (InterruptedExceptione) {
e.printStackTrace();
                    }
repaint();
                }
            }
        }.start();
    }
}