Paint program

[aarti bashyam]

I am writing a program where if the user clicks, it should draw a point. The following code does not seem to work properly. If I click, it draws a point but vanishes later on. I tried using paint and paint component but I am not able to use them. Please help!!

import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;


public class GUIClass extends JFrame{
/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
public Container c;
JButton jbtnStart;
JButton jbtnEnd;
JPanel panel;
Border border;
StartListener start;
ClickHandler click;
EndListener end;
Point point;
int width,height,x,y;
Image backbuffer;
Graphics bg;

public static void main (String[] args)
{
	new GUIClass();
}

GUIClass()
{
	Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
	setSize(screenSize);
	setResizable (false);
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	c = getRootPane();                                                       
	c.setLayout(null);
	
	panel = new JPanel();
	panel.setBounds(10,10,screenSize.width-30,screenSize.height-100);
	border = BorderFactory.createLineBorder(Color.black,4);
	panel.setBackground(Color.WHITE);
	panel.setBorder(border);
	click = new ClickHandler();
	panel.addMouseListener(click);
	c.add(panel);
	
	jbtnStart = new JButton("START");
	jbtnStart.setBounds(750, screenSize.height-80, 100, 50);
	start = new StartListener();
	jbtnStart.addActionListener(start);
	c.add(jbtnStart);
	
	jbtnEnd = new JButton("END");
	jbtnEnd.setBounds(900, screenSize.height-80, 100, 50);
	end = new EndListener();
	jbtnEnd.addActionListener(end);
	c.add(jbtnEnd);
	
	setVisible(true);
	
}


class StartListener implements ActionListener
{
	public void actionPerformed(ActionEvent e1)
	{
		
	}
}
class EndListener implements ActionListener
{
	public void actionPerformed(ActionEvent e1)
	{
		System.exit(0);
	}
}
/*public void update(Graphics g)
{
	
	bg.fillOval(x-5, y-5, 10, 10);
}
public void paintComponent (Graphics g)
{
	super.paint(g);
	bg.fillOval(x-5, y-5, 10, 10);
	update(g);
}*/

class ClickHandler implements MouseListener
{
	@Override
	public void mouseClicked(MouseEvent e) {
		// TODO Auto-generated method stub
		
	}

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

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

	@Override
	public void mousePressed(MouseEvent e) {
		// TODO Auto-generated method stub
		 x = e.getX();
		 y = e.getY();
		System.out.println(x+" "+y);
		bg = panel.getGraphics();
		bg.fillOval(x, y, 50, 50);
		repaint();
		e.consume();
	}
	@Override
	public void mouseReleased(MouseEvent e) {
		// TODO Auto-generated method stub
		
	}
}
}

[Rob Camick]

Please use the "Code" tags when posting code.

You can start with the Swing tutorial on Custom Painting for a working example that you can modify.

[Yunnan Zhou]

just remove repaint() in you method mousePressed() and try again.but it's not a good way.
if you want your points stay and not vanishes.you must save them in a collection .everytimes you press ,repaint all point which in you collection.

[Darryl Burke]

aarti, welcome to the Ranch! We don't have too many rules around here, but we do ask that you BeForthrightWhenCrossPostingToOtherSites <-- link

[Campbell Ritchie]

I think this discussion ought to be moved to our GUIs forum