恋足文章踩踏部落:JAVA做WINDOWS画图板的源程序？

楼上的代码我做了一点点改正，我想现在可以正常运行了：
//#8.15
//#filename: ShapeMain.java
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.MouseMotionListener;

import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
//import javax.swing.Component;

public class ShapeMain extends JFrame implements ActionListener,MouseListener,MouseMotionListener{
int x,y,x1,y1,x2,y2,width,height;
boolean isFirstPoint = true;
//初始化开始画的是线
int drawType = PaintingGround.LINE;
//初始化开始不是填充
boolean isFill = false;
//添加控件
ButtonGroup btg = new ButtonGroup();
Button btLine = new Button("线");
Button btRectangle = new Button("矩形");
Button btRound = new Button("圆");
Button btEllipse = new Button("椭圆");
Button tbFillState = new Button("填充");
Button button3 = new Button("文本操作");
Button button2 = new Button("清除");
Button button1 = new Button("选择颜色");

Panel buttonPanel = new Panel();
PaintingGround paintingGround = new PaintingGround();
//Main Method
public static void main(String[] args) {
//设置显示外观
try{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}catch(Exception e) {
e.printStackTrace();
}
new ShapeMain();
}

//构造函数
public ShapeMain() {
//控件添加到控件组中
// btg.add(btLine);
// btg.add(btRectangle);
// btg.add(btRound);
// btg.add(btEllipse);

buttonPanel.add(btLine);
buttonPanel.add(btRectangle);
buttonPanel.add(btRound);
buttonPanel.add(btEllipse);
buttonPanel.add(tbFillState);

//设置容器及容器的整体布局
Container cp = this;

cp.setLayout(new BorderLayout());

cp.add(BorderLayout.NORTH,buttonPanel);
cp.add(BorderLayout.CENTER,paintingGround);
//cp.add(BorderLayout.SOUTH,jf);
//jf.setJMenuBar(mb);
setLocation(300,150);
setSize(600,480);
setVisible(true);

setDefaultCloseOperation(EXIT_ON_CLOSE);
//添加鼠标触发事件
paintingGround.addMouseListener(new MouseAdapter() {
public void mouseReleased(MouseEvent evn) {
isFirstPoint = true;
}
});
//对鼠标的输入进行判断并调用画图程序
paintingGround.addMouseMotionListener(new MouseMotionAdapter() {
public void mouseDragged(MouseEvent evn) {
if(isFirstPoint) {
x1 = evn.getX();
y1 = evn.getY();
isFirstPoint = false;
}
else {
x2 = evn.getX();
y2 = evn.getY();
switch(drawType) {
case PaintingGround.LINE:
//画线
paintingGround.drawLine(x1,y1,x2,y2);
break;
case PaintingGround.RECTANGLE:
//画矫形
paintingGround.drawRect(x1,y1,x2-x1,y2-y1);
break;
case PaintingGround.ROUND:
//画圆
//两点距离公式
int size = Math.abs((int)Math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1)));
paintingGround.drawRound(x1,y1,size);
break;
case PaintingGround.ELLIPSE:
//画椭圆
paintingGround.drawEllipse(x1,y1,x2-x1,y2-y1);
break;
default:
break;
}
}
}
});
//各个控件的触发事件
btLine.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evn) {
drawType = PaintingGround.LINE;
}
});

btRectangle.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evn) {
drawType = PaintingGround.RECTANGLE;
}
});

btRound.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evn) {
drawType = PaintingGround.ROUND;
}
});

btEllipse.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evn) {
drawType = PaintingGround.ELLIPSE;
}
});

tbFillState.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent evn) {
isFill = tbFillState.isShowing();
paintingGround.setFillState(isFill);
}
});
}

public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub

}

public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub

}

public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub

}
}

class PaintingGround extends JPanel {
public static final int LINE = 1;
public static final int RECTANGLE = 2;
public static final int ROUND = 3;
public static final int ELLIPSE = 4;

private int x,y;
private int x1,y1,x2,y2;
private int width, height,size;
private int drawType = 0;
private boolean isFill = false;
//构造函数
public PaintingGround() {
setBackground(Color.black);
}
//判断是用实心还是空心的,
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.white);
if(isFill) {
switch(drawType) {
case LINE:
g.drawLine(x1,y1,x2,y2);
break;
case RECTANGLE:
g.fillRect(x,y,width,height);
break;
case ROUND:
g.fillOval(x,y,size,size);
break;
case ELLIPSE:
g.fillOval(x,y,width,height);
break;
default:
break;
}
}
else {
switch(drawType) {
case LINE:
g.drawLine(x1,y1,x2,y2);
break;
case RECTANGLE:
g.drawRect(x,y,width,height);
break;
case ROUND:
g.drawOval(x,y,size,size);
break;
case ELLIPSE:
g.drawOval(x,y,width,height);
break;
default:
break;
}
}
}

public void drawLine(int x1, int y1, int x2,int y2) {
this.x1 = x1;
this.y1 = y1;
this.x2 = x2;
this.y2 = y2;

drawType = LINE;
repaint();
}
//具体的实现方式
public void drawRect(int x,int y,int width, int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
drawType = RECTANGLE;
repaint();
}

public void drawRound(int x,int y,int size) {
this.x = x;
this.y = y;
this.size = size;
drawType = ROUND;
repaint();
}

public void drawEllipse(int x,int y,int width,int height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
drawType = ELLIPSE;
repaint();
}

public void setFillState(boolean isFill) {
this.isFill = isFill;
}

}