Draw with single mouse click, help me!!!!

Question

I am using this code - as you understood from it- to paint with the mouse click.
please help me either by completing it or by telling me what to do.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Hello extends JFrame{
     Graphics g;
     ImageIcon icon = new ImageIcon("hello.gif");
     public Hello(){
          super("Hello");
          setSize(200, 200);
          addMouseListener(
               new MouseAdapter(){
                    public void mouseClicked(MouseEvent e){
                         icon.paintIcon(Hello.this, g, e.getX(), e.getY());
                         g.fillRect(10, 40, 10, 80);
                         JOptionPane.showMessageDialog(Hello.this, e.getX() + ", " + e.getY());
                         //repaint();
     // i have tried to place this listener in the paint method, but no way out.
          setVisible(true);
     public void paint(final Graphics g){
          this.g = g;
          icon.paintIcon(this, g, 100, 50);
     public static void main(String[] args){
          new Hello();
**

Answer 1

You can't save a graphics object like that and then paint on it.
What you need is to use a BufferedImage, paint on that, and then paint that to the screen.
See my paintarea class. You are welcome to use + modify this class as well as take any code snippets to fit into whatever you have but please add a comment where ever you've incorporated stuff from my class
PaintArea.java
===========
* Created on Jun 15, 2005 by @author Tom Jacobs
package tjacobs.ui;
import java.awt.image.BufferedImage;
import java.awt.*;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.ImageIcon;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.SwingUtilities;
import tjacobs.MathUtils;
* PaintArea is a component that you can draw in similar to but
* much simpler than the windows paint program.
public class PaintArea extends JComponent {
     BufferedImage mImg; //= new BufferedImage();
     int mBrushSize = 1;
     private boolean mSizeChanged = false;
     private Color mColor1, mColor2;
     static class PaintIcon extends ImageIcon {
          int mSize;
          public PaintIcon(Image im, int size) {
               super(im);
               mSize = size;
     public PaintArea() {
          super();
          setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
          addComponentListener(new CListener());
          MListener ml = new MListener();
          addMouseListener(ml);
          addMouseMotionListener(ml);
          setBackground(Color.WHITE);
          setForeground(Color.BLACK);
     public void paintComponent(Graphics g) {
          if (mSizeChanged) {
               handleResize();
          //g.drawImage(mImg, mImg.getWidth(), mImg.getHeight(), null);
          g.drawImage(mImg, 0, 0, null);
          //super.paintComponent(g);
          //System.out.println("Image = " + mImg);
          //System.out.println("Size: " + mImg.getWidth() + "," + mImg.getHeight());
     public void setBackground(Color c) {
          super.setBackground(c);
          if (mImg != null) {
               Graphics g = mImg.getGraphics();
               g.setColor(c);
               g.fillRect(0, 0, mImg.getWidth(), mImg.getHeight());
               g.dispose();
     public void setColor1(Color c) {
          mColor1 = c;
     public void setColor2(Color c) {
          mColor2 = c;
     public Color getColor1() {
          return mColor1;
     public Color getColor2() {
          return mColor2;
     class ToolBar extends JToolBar {
          ToolBar() {
               final ColorButton fore = new ColorButton();
               fore.setToolTipText("Foreground Color");
               final ColorButton back = new ColorButton();
               back.setToolTipText("Background Color");
               JComboBox brushSize = new JComboBox();
               //super.createImage(1, 1).;
               FontMetrics fm = new FontMetrics(getFont()) {};
               int ht = fm.getHeight();
               int useheight = fm.getHeight() % 2 == 0 ? fm.getHeight() + 1 : fm.getHeight();
               final BufferedImage im1 = new BufferedImage(useheight, useheight, BufferedImage.TYPE_INT_RGB);
               Graphics g = im1.getGraphics();
               g.setColor(Color.WHITE);
               g.fillRect(0, 0, useheight, useheight);
               g.setColor(Color.BLACK);
               g.fillOval(useheight / 2, useheight / 2, 1, 1);
               g.dispose();
               //im1.setRGB(useheight / 2 + 1, useheight / 2 + 1, 0xFFFFFF);
               final BufferedImage im2 = new BufferedImage(useheight, useheight, BufferedImage.TYPE_INT_RGB);
               g = im2.getGraphics();
               g.setColor(Color.WHITE);
               g.fillRect(0, 0, useheight, useheight);
               g.setColor(Color.BLACK);
               g.fillOval(useheight / 2 - 1, useheight / 2 - 1, 3, 3);
               g.dispose();
//               im2.setRGB(useheight / 2 - 1, useheight / 2 - 1, 3, 3, new int[] {     0, 0xFFFFFF, 0,
//                                                            0xFFFFFF, 0xFFFFFFF, 0xFFFFFF,
//                                                            0, 0xFFFFFF, 0}, 0, 1);
               final BufferedImage im3 = new BufferedImage(useheight, useheight, BufferedImage.TYPE_INT_RGB);
               g = im3.getGraphics();
               g.setColor(Color.WHITE);
               g.fillRect(0, 0, useheight, useheight);
               g.setColor(Color.BLACK);
               g.fillOval(useheight / 2 - 2, useheight / 2 - 2, 5, 5);
               g.dispose();
//               im3.setRGB(useheight / 2 - 2, useheight / 2 - 2, 5, 5, new int[] {     0, 0, 0xFFFFFF, 0, 0, 
//                                                            0, 0xFFFFFF, 0xFFFFFFF, 0xFFFFFF, 0,
//                                                            0xFFFFFF, 0xFFFFFF, 0xFFFFFF, 0xFFFFFF, 0xFFFFFF,
//                                                            0, 0xFFFFFF, 0xFFFFFFF, 0xFFFFFF, 0,
//                                                            0, 0, 0xFFFFFF, 0, 0}, 0, 1);
               //JLabel l1 = new JLabel("1 pt", new ImageIcon(im1), JLabel.LEFT);
               //JLabel l2 = new JLabel("3 pt", new ImageIcon(im2), JLabel.LEFT);
               //JLabel l3 = new JLabel("5 pt", new ImageIcon(im3), JLabel.LEFT);
               brushSize.addItem(new PaintIcon(im1, 1));
               brushSize.addItem(new PaintIcon(im2, 3));
               brushSize.addItem(new PaintIcon(im3, 5));
               //brushSize.addItem("Other");
               add(fore);
               add(back);
               add(brushSize);
               PropertyChangeListener pl = new PropertyChangeListener() {
                    public void propertyChange(PropertyChangeEvent ev) {
                         Object src = ev.getSource();
                         if (src != fore && src != back) {
                              return;
                         Color c = (Color) ev.getNewValue();
                         if (ev.getSource() == fore) {
                              mColor1 = c;
                         else {
                              mColor2 = c;
               fore.addPropertyChangeListener("Color", pl);
               back.addPropertyChangeListener("Color", pl);
               fore.changeColor(Color.BLACK);
               back.changeColor(Color.WHITE);
               brushSize.addItemListener(new ItemListener() {
                    public void itemStateChanged(ItemEvent ev) {
                         System.out.println("ItemEvent");
                         if (ev.getID() == ItemEvent.DESELECTED) {
                              return;
                         System.out.println("Selected");
                         Object o = ev.getItem();
                         mBrushSize = ((PaintIcon) o).mSize;
               //Graphics g = im1.getGraphics();
               //g.fillOval(0, 0, 1, 1);
               //BufferedImage im1 = new BufferedImage();
               //BufferedImage im1 = new BufferedImage();
     protected class MListener extends MouseAdapter implements MouseMotionListener {
          Point mLastPoint;
          public void mouseDragged(MouseEvent me) {
               Graphics g = mImg.getGraphics();
               if ((me.getModifiers() & InputEvent.BUTTON1_MASK) != 0) {
                    g.setColor(mColor1);
               } else {
                    g.setColor(mColor2);
               Point p = me.getPoint();
               if (mLastPoint == null) {
                    g.fillOval(p.x - mBrushSize / 2, p.y - mBrushSize / 2, mBrushSize, mBrushSize);
                    //g.drawLine(p.x, p.y, p.x, p.y);
               else {
                    g.drawLine(mLastPoint.x, mLastPoint.y, p.x, p.y);
                    //g.fillOval(p.x - mBrushSize / 2, p.y - mBrushSize / 2, mBrushSize, mBrushSize);
                    double angle = MathUtils.angle(mLastPoint, p);
                    if (angle < 0) {
                         angle += 2 * Math.PI;
                    double distance = MathUtils.distance(mLastPoint, p) * 1.5;
                    if (angle < Math.PI / 4 || angle > 7 * Math.PI / 4 || Math.abs(Math.PI - angle) < Math.PI / 4) {
                         for (int i = 0; i < mBrushSize / 2; i ++) {
                              g.drawLine(mLastPoint.x, mLastPoint.y + i, p.x, p.y + i);
                              g.drawLine(mLastPoint.x, mLastPoint.y - i, p.x, p.y - i);
//                              System.out.println("y");
//                              System.out.println("angle = " + angle / Math.PI * 180);
                    else {
                         for (int i = 0; i < mBrushSize / 2; i ++) {
                              g.drawLine(mLastPoint.x + i, mLastPoint.y, p.x + i, p.y);
                              g.drawLine(mLastPoint.x  - i, mLastPoint.y, p.x - i, p.y);
//                              System.out.println("x");
//                    System.out.println("new = " + PaintUtils.printPoint(p));
//                    System.out.println("last = " + PaintUtils.printPoint(mLastPoint));
                    //System.out.println("distance = " + distance);
                    //Graphics2D g2 = (Graphics2D) g;
                    //g2.translate(mLastPoint.x + mBrushSize / 2, mLastPoint.y);
                    //g2.rotate(angle);
                    //g2.fillRect(0, 0, (int) Math.ceil(distance), mBrushSize);
                    //g2.rotate(-angle);
                    //g2.translate(-mLastPoint.x + mBrushSize / 2, -mLastPoint.y);
//                    g.setColor(Color.RED);
//                    g.drawRect(p.x, p.y, 1, 1);
               mLastPoint = p;
               g.dispose();
               repaint();
          public void mouseMoved(MouseEvent me) {}
          public void mouseReleased(MouseEvent me) {
               mLastPoint = null;
     private void handleResize() {
          Dimension size = getSize();
          mSizeChanged = false;
          if (mImg == null) {
               mImg = new BufferedImage(size.width, size.height, BufferedImage.TYPE_INT_RGB);
               Graphics g = mImg.getGraphics();
               g.setColor(getBackground());
               g.fillRect(0, 0, mImg.getWidth(), mImg.getHeight());
               g.dispose();
          else {
               int newWidth = Math.max(mImg.getWidth(),getWidth());
               int newHeight = Math.max(mImg.getHeight(),getHeight());
               if (newHeight == mImg.getHeight() && newWidth == mImg.getWidth()) {
                    return;
               BufferedImage bi2 = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
               Graphics g = bi2.getGraphics();
               g.setColor(getBackground());
               g.fillRect(0, 0, bi2.getWidth(), bi2.getHeight());
               g.drawImage(mImg, mImg.getWidth(), mImg.getHeight(), null);
               g.dispose();
               mImg = bi2;
     public JToolBar getToolBar() {
          if (mToolBar == null) {
               mToolBar = new ToolBar();
          return mToolBar;
     private ToolBar mToolBar;
     public static void main (String args[]) {
          PaintArea pa = new PaintArea();
          JPanel parent = new JPanel();
          parent.setLayout(new BorderLayout());
          parent.add(pa, BorderLayout.CENTER);
          pa.setPreferredSize(new Dimension(150, 150));
          parent.add(pa.getToolBar(), BorderLayout.NORTH);
          WindowUtilities.visualize(parent);
     protected class CListener extends ComponentAdapter {
          public void componentResized(ComponentEvent ce) {
               mSizeChanged = true;
}