//  Scott DeRuiter          11/30/2000
//  KeyMove.java
//  Use the left, right, up, and down arrows to move a ball around the screen.
//	3/13/2013 Greenstein: changed applet to JFrame


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

public class KeyMove implements KeyListener, FocusListener, MouseListener   
{

	private int xpos, ypos, radius;
	private boolean covertracks;

	private JFrame frame;
	private DrawingArea canvas;

	public KeyMove ( )   
	{
		xpos = ypos = 5;
		radius = 50;
		covertracks = true;
	}
	
	public static void main(String[] args) 
	{
		KeyMove km = new KeyMove();
		km.Run();
	}

	public void Run ( )   
	{
		// Create a frame to hold everything
		frame = new JFrame ("KeyMove");
		frame.setSize(500, 500);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//frame.setBackground(Color.black);	// only needed if frame is larger than panel
		
		// Define panel to draw on
		canvas = new DrawingArea();		// create a panel to draw on
      		canvas.setBackground(Color.gray);
		canvas.addFocusListener(this);
		canvas.addKeyListener(this);
		canvas.addMouseListener(this);	// connects the MouseListerner to the panel window
		
		// Put frame together
		frame.getContentPane().add(canvas);	// puts panel on frame
		frame.setVisible(true);
	}

	class DrawingArea extends JPanel 
	{
		public void paintComponent(Graphics g) 
		{
			super.paintComponent(g);
			g.setColor ( Color.blue );
			g.fillOval ( xpos, ypos, 2 * radius, 2 * radius );
		}
	}

	public void focusGained(FocusEvent evt) 
	{
		canvas.repaint();
	}
   
	public void focusLost(FocusEvent evt) 
	{
		canvas.repaint();
	}

	public void mousePressed(MouseEvent evt) 
	{
		canvas.requestFocus();
	}   
   
   public void mouseEntered(MouseEvent evt) { }
	public void mouseExited(MouseEvent evt) { }
	public void mouseReleased(MouseEvent evt) { }
	public void mouseClicked(MouseEvent evt) { }
   
	public void keyTyped ( KeyEvent e )   {}

	public void keyPressed ( KeyEvent e )    
	{
		int value = e.getKeyCode();
		if ( value == KeyEvent.VK_DOWN )
			ypos += 8;
		else if ( value == KeyEvent.VK_UP )
			ypos -= 8;
		else if ( value == KeyEvent.VK_RIGHT )
			xpos += 8;
		else if ( value == KeyEvent.VK_LEFT )
			xpos -= 8;
		else if ( value == KeyEvent.VK_ENTER )
		{
			xpos = (int)( Math.random ( ) * ( 500 - (2 * radius) ) );
			ypos = (int)( Math.random ( ) * ( 500 - (2 * radius) ) );
		}
		canvas.repaint ( );
	}

	public void keyReleased ( KeyEvent e )   {}
}