Question

JAVA 编辑 小球在一个框里做连续的碰撞运动

如题，并且是随机发的球，
是说建一个框 在框的边线上随机发出一个球，球做直线运动，当遇的边线时，成角度的反弹，遇到另一条线 再成角度的反弹，如此循环下去
思路我知道，就是不知道怎么写啊， 我才学了半个月啊
麻烦给写出来啊

Answer 1

/*
 * 一个在窗体中来回运动的圆.java
 *
 * Created on 2005年10月5日, 下午1:02
 *
 * To change this template, choose Tools | Options and locate the template under
 * the Source Creation and Management node. Right-click the template and choose
 * Open. You can then make changes to the template in the Source Editor.
 */
 
package javaapplication1;
 
import java.applet.Applet;
import <a href="https://www.baidu.com/s?wd=java.awt.Color&tn=44039180_cpr&fenlei=mv6quAkxTZn0IZRqIHckPjm4nH00T1Y3uhPWrjRdmHTdmWR4nWn40ZwV5Hcvrjm3rH6sPfKWUMw85HfYnjn4nH6sgvPsT6KdThsqpZwYTjCEQLGCpyw9Uz4Bmy-bIi4WUvYETgN-TLwGUv3EPHRYnHmYnHRYPW6knH63P1nz" target="_blank" class="baidu-highlight">java.awt.Color</a>;
import java.awt.Event;
import java.awt.Graphics;
import java.applet.*;
import java.awt.*;
import java.math.*;
/**
 *
 * @author Bachelorlrz
 */
public class 在窗体中来回运动的圆 extends java.applet.Applet implements java.lang.Runnable {
    int cx,cy,c1x,c1y;    //圆的坐标
    int cw,ch;            //圆的宽高
    int bx,by,bw,bh;      //背景的坐标和宽高
    int dx,dx1;           //圆的运动
    int r,rx,ry;          //圆的半径和位置 
    int r1,r1x,r1y;
    Thread u_thread;
     
    /** Initialization method that will be called after the applet is loaded
     *  into the browser.
     */
    public void init() {
        rx=150;             ry=160;
        bw=500;             bh=400;
        r1x=bw/2-cw*2;        r1y=bh/2-ch;
        r=60;               r1=200;
        cx =rx;             cy =ry;
        c1x=r1x;            c1y=r1y;
        cw=30;              ch=30;
        bx=2;               by=2;
        dx=1;               dx1=2;         
        // TODO start asynchronous download of heavy resources
    }
     
    // TODO overwrite start(), stop() and destroy() methods
 
    public void update(java.awt.Graphics g) {
        
        super.paint(g);
        g.setColor(Color.red);
        g.drawRect(bx,by,bw,bh);
        g.setColor(Color.BLACK);
        g.fillRect(bx+2,by+2,bw-4,bh-4);
        g.drawString("在窗体中来回运动的圆", bw/2-60, bh/2);
          if (cx<rx-r  || cx>rx+r) {
            dx = -dx;  
         }
         if (c1x<r1x-r1  || c1x>r1x+r1) {
            dx1 = -dx1;  
         }
         
            cx =cx+dx;
            cy =(int)(dx*Math.sqrt(r*r-(cx-rx)*(cx-rx)))+ry;
            c1x =c1x+dx1;
            c1y =(int)(dx1/2*Math.sqrt(r1*r1-(c1x-r1x)*(c1x-r1x))/2);
        
       // g.drawArc(cx, cy, cw, ch, 0, 360);
         
        for(int i=0;i<8;i++){
            if (i%5 == 0){
                g.setColor(Color.black);                
            }else if ( i%5== 1) {
                g.setColor(Color.GREEN);
            }else if(i%5==2){
                g.setColor(Color.RED);
            }else if( i%5 ==3){
                g.setColor(Color.pink);
            }else {
                g.setColor(Color.orange);
            }                       
            g.drawLine(bx,by, cx+10,cy+i+10);
            g.drawLine(bx+bw,by+bh,cx+10,cy+i+10);
            g.drawLine(bx+bw,by, cx+10,cy+i+10);
            g.drawLine(bx,by+bh, cx+10,cy+i+10);
             
            g.drawLine(bx,by,-cx+bw-bx-cw+10,cy+i+10);
            g.drawLine(bx+bw,by+bh,-cx+bw-bx-cw+10,cy+i+10);
            g.drawLine(bx+bw,by,-cx+bw-bx-cw+10,cy+i+10);
            g.drawLine(bx,by+bh,-cx+bw-bx-cw+10,cy+i+10);
             
            g.drawLine(bx,by, c1x+10,c1y+r1y+i+10);
            g.drawLine(bx+bw,by+bh,c1x+10,c1y+r1y+i+10);
            g.drawLine(bx+bw,by, c1x+10,c1y+r1y+i+10);
            g.drawLine(bx,by+bh, c1x+10,c1y+r1y+i+10);
             
            g.drawLine(bx,by, r1x+r1+cw-c1x+10,-c1y+r1y+i+10);
            g.drawLine(bx+bw,by+bh,r1x+r1+cw-c1x+10,-c1y+r1y+i+10);
            g.drawLine(bx+bw,by, r1x+r1+cw-c1x+10,-c1y+r1y+i+10);
            g.drawLine(bx,by+bh,r1x+r1+cw-c1x+10,-c1y+r1y+i+10);
             
            g.drawArc(cx+i, cy+i, cw-i*2, ch-i*2, 0, 360);
            g.drawArc(-cx+bw-bx-cw+i, cy+i, cw-i*2, ch-i*2, 0, 360);
            g.drawArc(c1x+i, c1y+r1y+i, cw-i*2, ch-i*2, 0, 360);
            g.drawArc(r1x+r1+cw-c1x+i, -c1y+r1y+i, cw-i*2, ch-i*2, 0, 360);
        }
    }
               public void start(){      
        if (u_thread == null)
        {
            u_thread  = new Thread(this);
            u_thread.start();
        }
    }
    public void run() {
        while(true){                              
                               repaint(); 
                               try{
                                     u_thread.sleep(10);
                                   }
                         catch (InterruptedException e){
                           return;
                                 }
        }
     }
}

Answer 2

建个项目
建个叫test的文件
建一个叫test的class文件，将代码复制进去就好


package test;
import java.awt.*;
import java.applet.*;
public class test extends Applet implements Runnable {
 private static final long serialVersionUID = 1L;
 int X, Y, moveX, moveY, width, height;
 Thread newThread;
 Image OffScreen;
 Graphics drawOffscreen;
 public void init() {
  X = 0;
  Y = 0;
  moveX = 10;      //水平移动的速度
  moveY = 15;       //垂直移动速度
  width = getSize().width ;    //窗口的宽度
  
  System.out.println("width = " + width);
  height = getSize().height ;
  System.out.println("height = " + height);
  
  OffScreen = createImage(width, height);        //创建背景
  drawOffscreen = OffScreen.getGraphics();
 }
 public void start()
 {
  newThread = new Thread(this);
  newThread.start();
 }
 public void stop()
 {
  newThread = null;
 }
 public void paint(Graphics g)
 {
  drawOffscreen.setColor(Color.black); // 设置背景色
  drawOffscreen.fillRect(0, 0, width, height); // 填充所在区域
  drawOffscreen.setColor(Color.white); // 设置球的颜色
  drawOffscreen.fillOval(X, Y, 15, 15);   //画球
  g.drawImage(OffScreen, 0, 0, this); // 画背景
 }
 public void update(Graphics g)
 {
  paint(g);
 }
 public void run()
 {
  while (newThread != null)
  {
   repaint();
   try
   {
    Thread.sleep(50);
   }
   catch (InterruptedException E) {
   }
   
   
   
   X = X + moveX;
   Y = Y + moveY;
   if (X >= (width - 15))
   {
    X = width - 15;
    moveX = -moveX;
   }
   if (X <= 0)
   {
    X = 0;
    moveX = -moveX;
   }
   if (Y >= (height - 15))
   {
    Y = height - 15;
    moveY = -moveY;
   }
   if (Y <= 0)
   {
    Y = 0;
    moveY = -moveY;
   }
  }
 }
}

Answer 3

用Jbox2d,建站world边界位置,设置弹力为1（永远不会损耗）

Answer 4

没时间了说说思路吧
添加文本框
TextField tf=new TextField(12);
画一个球 作为进度条
设定位置 随机数
控制，位置

Answer 5

三年前写的,那时候只能把它做出来.对付着看下吧.
import java.awt.event.*;
import java.awt.*;
public class QicaiXiaoqui extends Thread{
private Frame f;
private Label l1,l2,l3,l4;
private Button b1,b2,b3,b4;
private Panel p1,p2;
private ThreadGroup th;
private int i=0;
public QicaiXiaoqui(){
th=new ThreadGroup("one");
f=new Frame();
l1=new Label();
l2=new Label();
l3=new Label();
l4=new Label("");
b1=new Button("start");
b2=new Button("pause");
b3=new Button("continue");
b4=new Button("stop");
p1=new Panel();
p2=new Panel();
f.setLayout(null);
p1.setLayout(null);
p2.setLayout(new GridLayout());
l1.setBounds(0,0,600,55);
l2.setBounds(0,0,30,470);
l3.setBounds(570,0,30,470);
l4.setBounds(0,445,600,30);
p2.setBounds(0,473,600,30);
p1.setBounds(30,55,545,390);

f.add(l1);
f.add(l2);
f.add(l3);
f.add(l4);
f.add(p2);
f.add(p1);

p2.add(b1);
p2.add(b2);
p2.add(b3);
p2.add(b4);

l1.setBackground(new Color(239,143,159));
l2.setBackground(new Color(239,143,159));
l3.setBackground(new Color(239,143,159));
l4.setBackground(new Color(239,143,159));
b2.setBackground( new Color(209,000,251));
b1.setBackground(new Color(255,169,002));
b3.setBackground(new Color(255,100,255));
b4.setBackground(new Color(29,116,046));
p1.setBackground(Color.green);

b2.setEnabled(false);
b3.setEnabled(false);
f.setResizable(false);
f.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
th.stop();
f.setVisible(false);
f.dispose();
}
});
b1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
Thread x=new Thread(th,QicaiXiaoqui.this);
x.start();
i++;
}
});
b2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
b1.setEnabled(false);
b3.setEnabled(true);
th.suspend();
b2.setEnabled(false);
}
});
b3.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
b1.setEnabled(true);
b2.setEnabled(true);
th.resume();
b3.setEnabled(false);
}
});
b4.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
th.stop();
f.setVisible(false);
f.dispose();
System.out.println("stop");
}
});
f.setSize(600,500);
f.setVisible(true);

}
public void run(){

b2.setEnabled(true);
l2.setText(" "+i);
l3.setText(" "+i);
Button bb=new Button();
bb.setBounds(250,380,10,10);
p1.add(bb);
//ﾑﾕﾉｫ
int r=(int)(Math.random()*254+1);
int g=(int)(Math.random()*254+1);
int b=(int)(Math.random()*254+1);

bb.setBackground(new Color(r,g,b));

int rx=(int)(Math.random()*-10)+5;
int ry=(int)(Math.random()*10);
while(true){
int x=bb.getX();
int y=bb.getY();
if(x<=0){
rx=-rx;
}
else if(x>=520){
rx=-rx;
}
else if(y<=0){
ry=-ry;
}
else if(y>=385){
ry=-ry;
}
else if(rx==0){
rx=-3;
}
else if(ry==0){
ry=3;
}
try{
Thread.sleep(2);
}
catch(InterruptedException e){
e.printStackTrace();
}
bb.setLocation(x-=rx,y-=ry);
}
}
public static void main(String[] args){
QicaiXiaoqui c=new QicaiXiaoqui();
}

};