Paintbrush In Java

[pph]

i m making a paint brush application using java applets and swings.intially i have only added 3 buttons ,line ,rect and oval .but while i m drawing ..after drawing one line ..if i want to draw another line the previous line gets erased. i.e it does not store the previous line . well i want to store the co-or of the last button click in an array and repaint it again .but i not understnding how to write the code for it .so plz help me wid this ..here is my code

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.lang.*;
import java.applet.*;

public class nbrush extends JFrame implements ActionListener {

JLabel jl;
JButton bLine, bRect, bOval;
Color c;
int x1, y1, x2, y2;
String msg = " ";
int mouseX = 0, mouseY = 0;
JFileChooser fc;
File file;

public nbrush() {
super("hello");

Container cont = new Container();
jl = new JLabel(" ");
JPanel pbuttons = new JPanel();
DrawingPanel drp = new DrawingPanel();
//JPanel pDraw = new JPanel();
JPanel pStatus = new JPanel();

fc = new JFileChooser();

pbuttons.setLayout(new GridLayout(9, 2));
GridLayout gl = new GridLayout(9, 2);

bLine = new JButton("line");
bRect = new JButton("rect");
bOval = new JButton("oval");


pbuttons.add(bLine);
pbuttons.add(bRect);
pbuttons.add(bOval);

JMenuBar mbr = new JMenuBar();
setJMenuBar(mbr);
JMenu file = new JMenu("FILE");
JMenu edit = new JMenu("EDIT");
JMenu view = new JMenu("VIEW");
JMenu image = new JMenu("IMAGE");
JMenu colors = new JMenu("COLORS");
JMenu help = new JMenu("HELP");

JMenuItem mit, mit1, mit2, mit3, mit4;
file.add(mit = new JMenuItem("new"));
file.add(mit1 = new JMenuItem("open"));
file.add(mit2 = new JMenuItem("save"));
file.add(mit3 = new JMenuItem("save as"));
file.add(mit4 = new JMenuItem("exit"));

JMenuItem mit5, mit6, mit7, mit8, mit9;
edit.add(mit5 = new JMenuItem("undo"));
edit.add(mit6 = new JMenuItem("redo"));
edit.add(mit7 = new JMenuItem("cut"));
edit.add(mit8 = new JMenuItem("copy"));
edit.add(mit9 = new JMenuItem("paste"));

JMenuItem bc;
colors.add(bc = new JMenuItem("setbackground"));
bc.addActionListener(new MyAction());

bLine.addActionListener(drp);
bRect.addActionListener(drp);
bOval.addActionListener(drp);

mit.addActionListener(new MyAction());
mit1.addActionListener(new MyAction());
mit2.addActionListener(new MyAction());
mit3.addActionListener(new MyAction());
mit4.addActionListener(new MyAction());
mit5.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {
jl.setText("undo is clicked");
}
});

mit6.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {
jl.setText("redo is clicked");
}
});

mit7.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {
//jl.setText("cut is clicked");

}
});
mit8.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {
jl.setText("copy as is clicked");
}
});
mit9.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent ae) {
jl.setText("paste is clicked");
}
});


mbr.add(file);
mbr.add(edit);
mbr.add(view);
mbr.add(image);
mbr.add(colors);
mbr.add(help);
cont = getContentPane();
cont.setLayout(new BorderLayout());
cont.add(mbr, BorderLayout.NORTH);
cont.add(pbuttons, BorderLayout.WEST);
cont.add(drp,BorderLayout.CENTER);
cont.add(jl, BorderLayout.SOUTH);


setSize(660, 490);
this.setResizable(true);
setVisible(true);
} //.......end of nbrush constructor





class DrawingPanel extends JPanel implements ActionListener
{
int chr=0;

DrawingPanel()
{
MouseHandler handler = new MouseHandler();
this.addMouseListener(handler);
this.addMouseMotionListener(handler);

/*--------------------------------*/
addWindowListener (
new WindowAdapter ()
{
public void windowClosing (WindowEvent e)
{
System.exit(0);
}

}
);

setBackground (Color.white);
setForeground(Color.black);

}

public void paintComponent(Graphics g)
{
super.paintComponent(g);
switch (chr)
{
case 1:

g.drawLine(x1,y1,x2,y2);

break;

case 2:

g.drawRect(x1,y1,x2,y2);
break;

case 3:

g.drawOval(x1,y1,x2,y2);

break;

}
} // end paintComponent

void clear()
{
repaint();
}


public void actionPerformed(ActionEvent ae)
{
String command = ae.getActionCommand();
if (command.equals("line"))
{
chr=1;

}
if (command.equals("rect"))
{
chr=2;
}
if (command.equals("oval"))
{
chr=3;
}
}

}

/*-----------------------------------------------------------------------giving event sfor file,edit,...etc--------------*/
public class MyAction implements ActionListener {

public void actionPerformed(ActionEvent ae) {
String str = ae.getActionCommand();
if (str.equals("new")) {

}
if (str.equals("open")) {
int returnVal = fc.showOpenDialog(nbrush.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
} else {
}
}
if (str.equals("save")) {
int returnVal = fc.showSaveDialog(nbrush.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
} else {
}
}

if (str.equals("save as")) {
int returnVal = fc.showSaveDialog(nbrush.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
} else {
}
}
if (str.equals("setbackground")) {
Color c = JColorChooser.showDialog(
nbrush.this, "Choose a color...", getBackground());
if (c != null) {
getContentPane().setBackground(c);
}
}
if (str.equals("exit")) {
System.exit(0);

}
}
}
/*----------------------------------------------------------------------------*/
private class MouseHandler implements MouseListener, MouseMotionListener
{
public void mouseClicked(MouseEvent me)
{
//mouseX=0;
//mouseY=0;
jl.setText("mouse clicked");
//repaint();
}
public void mouseEntered(MouseEvent me)
{
mouseX=0;
mouseY=0;
jl.setText("mouse enetered");
//repaint();
}
public void mouseExited(MouseEvent me)
{
mouseX=0;
mouseY=0;
jl.setText("mouse exited");
repaint();
}
public void mousePressed(MouseEvent me)
{
mouseX=me.getX();
x1=mouseX;
mouseY=me.getY();
y1=mouseY;
jl.setText( mouseX + " , " + mouseY);
repaint();
}
public void mouseReleased(MouseEvent me)
{
mouseX=me.getX();
x2=mouseX;
mouseY=me.getY();
y2=mouseY;
jl.setText(mouseX + " , " + mouseY);
repaint();
}
public void mouseDragged(MouseEvent me)
{
mouseX=me.getX();
mouseY=me.getY();
msg="*";
jl.setText("Draggingmouse at " + mouseX + " , " + mouseY);
//repaint();
}
public void mouseMoved(MouseEvent me)
{
jl.setText("movingmouse at " + me.getX() + " , " + me.getY());
}
public void paint(Graphics g)
{
g.drawString(" ",mouseX,mouseY);
}
}


public void actionPerformed(ActionEvent ae) {
}


public static void main(String args[]) {
nbrush dp = new nbrush();
dp.setVisible(true);
dp.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}