cannot draw graphics

[Jonathan Keller]

The goal of this program is to change the background to yellow when the mouse enters, change the background to black when the mouse exits, create a small circle on left click, and create a large circle on right click. The mouse enter and exit methods work just fine, but i cannot get it to draw the circles. Any help would be appreciated.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JMouseFrame extends JFrame implements MouseListener {
	int width = 0;
	int height = 0;
	int x = 0;
	int y = 0;
	
	public JMouseFrame(){
		setTitle("Mouse Frame");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		addMouseListener(this);
	}
	
	public void mouseClicked(MouseEvent e){
		int whichButton = e.getButton();
		if(whichButton == MouseEvent.BUTTON1){
			width = 20;
			height = 20;
			repaint();
		}
		else if(whichButton == MouseEvent.BUTTON2){
			width = 50;
			height = 50;
			repaint();
		}
		else
			repaint();
	}	

	public void mouseEntered(MouseEvent e) {
		Container con = getContentPane();
		con.setBackground(Color.YELLOW);
	}

	public void mouseExited(MouseEvent e) {
		Container con = getContentPane();
		con.setBackground(Color.BLACK);
	}

	public void mousePressed(MouseEvent e) {
	}

	public void mouseReleased(MouseEvent e) {
	}
	
	public void paint(Graphics g){
		super.paint(g);
		g.drawOval(getX(), getY(), width, height);
	}
	
	public static void main(String[] args){
		JMouseFrame frame = new JMouseFrame();
		frame.setSize(500, 500);
		frame.setVisible(true);
	}
}

[Tim Moores]

If you use Swing components (the ones named J...) you need to override paintComponent, not paint. See http://www.oracle.com/technetwork/java/painting-140037.html for details.

[Randall Twede]

tim is correct.
thanks jonathan for showing me how to tell which button was clicked.

[Jonathan Keller]

Maybe I am not understanding correctly, but isn't that why the first line of the paint method is super.paint(g)?

[Tim Moores]

No, paint should not be calling super.paint. And as I said, it's the wrong method for Swing components to override anyway.

[Rob Spoor]

Since this is a JFrame you can't override paintComponent because JFrame doesn't have a paintComponent method. Try creating a JPanel subclass instead:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class JMousePanel extends JPanel implements MouseListener {
    int width = 0;
    int height = 0;
    int x = 0;
    int y = 0;

    public JMousePanel(){
        addMouseListener(this);
    }

    public void mouseClicked(MouseEvent e){
        int whichButton = e.getButton();
        if(whichButton == MouseEvent.BUTTON1){
            width = 20;
            height = 20;
            repaint();
        }
        else if(whichButton == MouseEvent.BUTTON2){
            width = 50;
            height = 50;
            repaint();
        }
        else
            repaint();
    }

    public void mouseEntered(MouseEvent e) {
        setBackground(Color.YELLOW);
    }

    public void mouseExited(MouseEvent e) {
        setBackground(Color.BLACK);
    }

    public void mousePressed(MouseEvent e) {
    }

    public void mouseReleased(MouseEvent e) {
    }

    protected void paintComponent(Graphics g){
        super.paintComponent(g);
        g.drawOval(getX(), getY(), width, height);
    }

    public static void main(String[] args){
        JFrame frame = new JFrame();
        frame.setTitle("Mouse Frame");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new JMousePanel());
        frame.setSize(500, 500);
        frame.setVisible(true);
    }
}