import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

public class HuaTu implements MouseMotionListener,ActionListener{

static final int r=3;

static int ox, oy;

static int flag=1;

public static void main(String arg[]){

JFrame f=new JFrame("Paint");

Container p=f.getContentPane();

p.setLayout(new FlowLayout());

JButton jButton1 = new JButton("红");

JButton jButton2 = new JButton("黑");

JButton jButton3 = new JButton("退出");

//Graphics g.setColor(new Color(255,0,0));

//ButtonEvent arg=new ButtonEvent(arg);

jButton1.addActionListener(new HuaTu());

jButton2.addActionListener(new HuaTu());

jButton3.addActionListener(new HuaTu());

p.addMouseMotionListener(new HuaTu());

p.add(jButton1);

p.add(jButton2);

p.add(jButton3);

f.setSize(200,200);

f.show();

}

public void actionPerformed(ActionEvent e){

if(e.getActionCommand().equals("红")){

flag=1;

}

else if (e.getActionCommand().equals("黑")){

flag=2;

}

else if (e.getActionCommand().equals("退出"))

System.exit(0);

}

public void mouseDragged(MouseEvent e){

Container c=(Container)e.getSource();

Graphics g=c.getGraphics();

if (ox>=0) {

if(flag==1){

g.setColor(new Color(168,0,255));

g.drawLine(ox,oy,e.getX(),e.getY());}

else

{ g.setColor(new Color(0,0,0));

g.drawLine(ox,oy,e.getX(),e.getY());}

}

ox=e.getX();oy=e.getY();

}

public void mouseMoved(MouseEvent e){

ox=-1;oy=-1;

}

}