我java原代码的问题!

Question

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class Bounce{
public static void main(String[] args){
JFrame f1=new BounceFrame();
f1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f1.setVisible(true);
}
}
class Ball{
public void move(Rectangle2D bounds)
{
x+=dx;
y+=dy;
if(x<bounds.getMinX());
{
x=bounds.getMinX();
dx=-dx;
}
if(x+XSIZE>=bounds.getMaxX())
{
x=bounds.getMaxX()-XSIZE;
dx=-dx;
}
if(y<bounds.getMinY());
{
y=bounds.getMinY();
dy=-dy;
}
if(y+YSIZE>=bounds.getMaxY())
{
y=bounds.getMaxY()-YSIZE;
dy=-dy;
}
}
public Ellipse2D getShape()
{
return new Ellipse2D.Double(x,y,XSIZE,YSIZE);
}
private static final int XSIZE=15;
private static final int YSIZE=15;
private double x=0;
private double y=0;
private double dx=1;
private double dy=1;

}
class BallPanel extends JPanel
{
public void add(Ball b)
{
balls.add(b);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D) g;
for (Ball b : balls)       /*此处有错误,不知道":"符号是干吗用的!*/
{
g2.fill(b.getShape());
}
}
private ArrayList<Ball> balls=new ArrayList<Ball>();/*此处有错误,不知ArrayList*/
//private Ball balls=new Ball();
}
class BounceFrame extends JFrame
{
public BounceFrame()
{
this.setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
this.setTitle("Bounce");
panel=new BallPanel();
this.add(panel,BorderLayout.CENTER);
JPanel buttonPanel=new JPanel();
addButton(buttonPanel,"Start",
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
addBall();
}
});
addButton(buttonPanel,"Close",
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
System.exit(0);
}
});
add(buttonPanel,BorderLayout.SOUTH);
}
public void addButton(Container c,String title,ActionListener listener)
{
JButton button=new JButton(title);
c.add(button);
button.addActionListener(listener);
}
public void addBall();
{
try
{
Ball ball=new Ball();
panel.add(ball);
for(int i=1;i<STEPS;i++)
{
ball.move(panel.getBounds());
panel.paint(panel.getGraphics());
Thread.sleep(DELAY);
}
}
catch(InterruptedException e)
{
}

}
private BallPanel panel;
public static final int DEFAULT_WIDTH=450;
public static final int DEFAULT_HEIGHT=350;
public static final int STEPS=1000;
public static final int DELAY=3;
}

Answer 1

多了三个分号“；”public void addBall();if(x<bounds.getMinX());
if(y<bounds.getMinY());

Answer 2

package StudyTest;import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class Bounce{
public static void main(String[] args){
JFrame f1=new BounceFrame();
f1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f1.setVisible(true);
}
}
class Ball{
public void move(Rectangle2D bounds)
{
x+=dx;
y+=dy;
if(x<bounds.getMinX());
{
x=bounds.getMinX();
dx=-dx;
}
if(x+XSIZE>=bounds.getMaxX())
{
x=bounds.getMaxX()-XSIZE;
dx=-dx;
}
if(y<bounds.getMinY());
{
y=bounds.getMinY();
dy=-dy;
}
if(y+YSIZE>=bounds.getMaxY())
{
y=bounds.getMaxY()-YSIZE;
dy=-dy;
}
}
public Ellipse2D getShape()
{
return new Ellipse2D.Double(x,y,XSIZE,YSIZE);
}
private static final int XSIZE=15;
private static final int YSIZE=15;
private double x=0;
private double y=0;
private double dx=1;
private double dy=1;

}
class BallPanel extends JPanel
{
public void add(Ball b)
{
balls.add(b);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2=(Graphics2D) g;
for (Ball b : balls)       /*此处有错误,不知道":"符号是干吗用的!*/
{
g2.fill(b.getShape());
}
}
private ArrayList<Ball> balls=new ArrayList<Ball>();/*此处有错误,不知ArrayList*/
//private Ball balls=new Ball();
}
class BounceFrame extends JFrame
{
public BounceFrame()
{
this.setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
this.setTitle("Bounce");
panel=new BallPanel();
this.add(panel,BorderLayout.CENTER);
JPanel buttonPanel=new JPanel();
addButton(buttonPanel,"Start",
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
addBall();
}
});
addButton(buttonPanel,"Close",
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
System.exit(0);
}
});
add(buttonPanel,BorderLayout.SOUTH);
}
public void addButton(Container c,String title,ActionListener listener)
{
JButton button=new JButton(title);
c.add(button);
button.addActionListener(listener);
}
public void addBall()
{
try
{
Ball ball=new Ball();
panel.add(ball);
for(int i=1;i<STEPS;i++)
{
ball.move(panel.getBounds());
panel.paint(panel.getGraphics());
Thread.sleep(DELAY);
}
}
catch(InterruptedException e)
{
}

}
private BallPanel panel;
public static final int DEFAULT_WIDTH=450;
public static final int DEFAULT_HEIGHT=350;
public static final int STEPS=1000;
public static final int DELAY=3;
}

Answer 3

cao
我头都晕了
你到底想要问什么

Answer 4

for (Ball b : balls)       /*此处有错误,不知道":"符号是干吗用的!*/
{
g2.fill(b.getShape());
}意思就是循环balls中的东西
这是jdk1.5中新提出来的

Answer 5

而且我也没有发现出现
很可能你是没有安装jdk1。5
所以导致你解析不了这两种类型