Thread: Moving circle problem help

In my program I need to create a circle that moves around in its panel that bounces off the sides in a realistic manner based off of physics. My program seems to work fine until the circle begins to move in a direction it has already moved in before. When this happens the circle starts moving in an erratic way and exits the panel. Also this only happens when it hits the X plane sides, not the top or bottom. Here's my code so far:

//panel
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
public class MovingCirclePanel extends JPanel
{
	private Circle circle, circle2;
	private javax.swing.Timer timer;
	private boolean move = true;
 
	public MovingCirclePanel(Color backColor, int width, int height)
	{
		setBackground(backColor);
		setPreferredSize(new Dimension(width, height));
 
		circle = new Circle(width / 2, height / 2, 25, Color.red);
		circle.setDirection(300);
		circle.setVelocity(5);
 
		circle2 = new Circle(width / 2, height / 2, 25, Color.blue);
		circle2.setDirection(0);
		circle2.setVelocity(5);
 
		timer = new javax.swing.Timer(5, new MoveListener());
		addMouseListener(new MouseListener());
		timer.start();
	}
 
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		circle.fill(g);
		circle2.fill(g);
	}
 
	private class MoveListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			int x = circle.getX();
			int radius = circle.getRadius();
			int width = getWidth();
			int y = circle.getY();
			int height = getHeight();
 
			int x2 = circle2.getX();
			int radius2 = circle2.getRadius();
			int y2 = circle2.getY();
 
			if(x - radius <= 0 || x + radius >= width)
			{	
				circle.turn(circle.getDirection() + 180);
			}
 
			if(y - radius <= 0 || y + radius >= height)
			{
				circle.turn(circle.getDirection() + 180);
			}		
 
			circle.move();
			repaint();		
 
		}
	}
 
	private class MouseListener extends MouseAdapter
	{
		public void mouseClicked(MouseEvent e)
		{
			if(move)
			{
				timer.stop();
				move = false;	
			}
 
			else
			{
				timer.start();
				move = true;
			}	
		}
	}
}
 
//Implementation of panel
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
public class MovingCircle
{
	public static void main(String[] args)
	{
		JFrame theGUI = new JFrame();
		theGUI.setTitle("Moving Circle");
		theGUI.setSize(800, 800);
		theGUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
		MovingCirclePanel panel = new MovingCirclePanel(Color.white, 200, 300);
 
		Container pane = theGUI.getContentPane();
		pane.add(panel);
 
		theGUI.setVisible(true);
	}
}

//circle class
import java.awt.*;
 
public class Circle
{
	private int centerX, centerY, radius, velocity, direction;
	private Color color;
 
	public Circle(int x, int y, int r, Color c)
	{
		centerX = x;
		centerY = y;
		radius = r;
		color = c;
	}
 
	public int getX()
	{
		return centerX;
	}
 
	public int getY()
	{
		return centerY;
	}
 
	public int getRadius()
	{
		return radius;
	}
 
	public void draw(Graphics g)
	{
		Color oldColor = g.getColor();
		g.setColor(color);
		g.drawOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
		g.setColor(oldColor);
	}
 
	public void fill(Graphics g)
	{
		Color oldColor = g.getColor();
		g.setColor(color);
		g.fillOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
	}
 
	public boolean containsPoint(int x, int y)
	{
		int xSquared = (x - centerX) * (x - centerX);
		int ySquared = (y - centerY) * (y - centerY);
		int radiusSquared = radius * radius;
		return xSquared + ySquared - radiusSquared <= 0;
	}
 
	public void move(int xAmount, int yAmount)
	{
		centerX = centerX + xAmount;
		centerY = centerY + yAmount;
	}
 
	public void setVelocity(int v)
	{
		velocity = v;
	}
 
	public void setDirection(int degrees)
	{
		direction = degrees % 360;
	}
 
	public void turn(int degrees)
	{
		direction = (direction + degrees) % 360;
	}
 
	public void move()
	{
		move((int)(velocity * Math.cos(Math.toRadians(direction))), (int)(velocity * Math.sin(Math.toRadians(direction))));
	}
 
	public int getDirection()
	{
		return direction;
	}
}

Any help is appreciated.

Sounds like your not setting the display positions correctly.
Have you tried debugging your code by displaying values using println()?
If you println() the variables as they change you should be able to see where your logic is bad.