我没用java写过代码，所以我只说算法，代码你自己翻译下
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按C的语法来：
void xiaoqiu
{
int UB=10,DB=200,LB=10,RB=200; //定义弹球范围的边界
int sh=1; //定义横向步长
int sz=1; //定义纵向步长（两步长之比决定了反弹的角度）
int x=LB,y=UB; //定义坐标
int i=10000; //循环次数（自己选择跳出手段）
while(i0)
{
i--;
x=x+sh;
if(x=RB||x=LB) sh=-sh; //碰壁后步长变反
y=y+sz;
if(y=DB||y=UB) sz=-sz; //碰壁后步长变反
(显示代码)
}
return;
}
总得来说，就是相当于横向和纵向分别处理移动、反弹的问题，碰壁后步长变为相反数
不懂请追问
这个问题主要的几点就是：移动与边界判断，小球与木板移动，这个通过修改座标来实现，边界判断，这个也通过座标值判断；移动的板跟随鼠标移动，通过MouseMotionListener监听鼠标移动，再修改木板座标实现；小球移动，设置2个方向，水平与垂直，0，座标值增加（向右或向下移动），0座标减小（向上或向左移动），到达边界后，修改方向值，使其向反方向移动。
因为，有大神先贴了代码，就不献丑了。如果需要代码，可以追问我。
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class CopyOfBallCrash implements Runnable {
public static void main(final String[] args) {
new Thread(new CopyOfBallCrash()).start();
}
private final int width = 400;
private final int height = 700;
private int mouse_X, mouse_Y;
private final BufferedImage offscreen = new BufferedImage(width, height,
BufferedImage.TYPE_4BYTE_ABGR);
private final JPanel panel = new JPanel();
private final Shape ball = new Shape(100, 100, 1, 1, 20);
private final Shape rect = new Shape(0, 100, 20);
public CopyOfBallCrash() {
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setPreferredSize(new Dimension(width, height));
ball.setBounds(width, height);
rect.setBounds(width, height);
frame.setContentPane(panel);
panel.addMouseMotionListener(new MouseMotionListener() {
@Override
public void mouseDragged(final MouseEvent e) {}
@Override
public void mouseMoved(final MouseEvent e) {
mouse_X = e.getX();
mouse_Y = e.getY();
}
});
frame.pack();
frame.setVisible(true);
}
public void paint(final Graphics g) {
final Graphics2D g2d = offscreen.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.fillRect(0, 0, width, height);
g2d.setColor(Color.blue);
rect.drawRect(g2d, mouse_X);
g2d.setColor(Color.red);
ball.drawOval(g2d, rect);
if (Shape.isLose) g2d.drawString("你输了!!!", 100, 300);
g2d.dispose();
g.drawImage(offscreen, 0, 0, null);
}
@Override
public void run() {
while (true)
paint(panel.getGraphics());
}
}
class Shape {
public int width, height;
public int x, y, vx, vy, r, w, h;
public static boolean isLose;
public Shape(final int x, final int y, final int vx, final int vy, final int r) {
super();
this.x = x;
this.y = y;
this.vx = vx;
this.vy = vy;
this.r = r;
}
public Shape(final int x, final int w, final int h) {
super();
this.x = x;
this.w = w;
this.h = h;
}
public final void setBounds(final int width, final int height) {
this.width = width;
this.height = height;
}
public final void drawOval(final Graphics2D g2d, final Shape shape) {
if (y + h = height) {
isLose = true;
return;
}
if (x + vx = 0 || x + vx + w = width) vx = -vx;
if (y + vy = 0) vy = -vy;
if (isCrashOutside(shape.x, shape.y, shape.w, shape.h) y + w = shape.y)
vy = -vy;
x += vx;
y += vy;
g2d.fillOval(x, y, r, r);
}
public final void drawRect(final Graphics2D g2d, final int mouseX) {
y = height - h;
if (x + w width x mouseX) x++;
if (x 0 x mouseX) x--;
g2d.fillRect(x, y, w, h);
}
public final boolean isCrashOutside(final int x, final int y, final int w,
final int h) {
return (this.x x ? this.x = w + x : x = r + this.x)
(this.y y ? this.y = h + y : y = r + this.y);
}
}
