import java.awt.*; import java.awt.event.*; import java.awt.geom.*; import java.util.*; import javax.swing.*;/** Shows an animated bouncing ball running in a separate thread */ public class BounceThread { public static void main(String[] args) { JFrame frame = new BounceFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.show(); } }/** The frame with canvas and buttons. */ class BounceFrame extends JFrame { /** Constructs the frame with the canvas for showing the bouncing ball and Start and Close buttons */ public BounceFrame() { setSize(WIDTH, HEIGHT); setTitle("BounceThread"); Container contentPane = getContentPane(); canvas = new BallCanvas(); contentPane.add(canvas, BorderLayout.CENTER); JPanel buttonPanel = new JPanel(); addButton(buttonPanel, "Start", new ActionListener() { public void actionPerformed(ActionEvent evt) { addBall(); } }); addButton(buttonPanel, "Close", new ActionListener() { public void actionPerformed(ActionEvent evt) { System.exit(0); } }); contentPane.add(buttonPanel, BorderLayout.SOUTH); } /** Adds a button to a container. @param c the container @param title the button title @param listener the action listener for the button */ public void addButton(Container c, String title, ActionListener listener) { JButton button = new JButton(title); c.add(button); button.addActionListener(listener); } /** Adds a bouncing ball to the canvas and starts a thread to make it bounce */ public void addBall() { Ball b = new Ball(canvas); canvas.add(b); BallThread thread = new BallThread(b); thread.start(); } private BallCanvas canvas; public static final int WIDTH = 450; public static final int HEIGHT = 350; }/** A thread that animates a bouncing ball. */ class BallThread extends Thread { /** Constructs the thread. @aBall the ball to bounce */ public BallThread(Ball aBall) { b = aBall; } public void run() { try { for (int i = 1; i <= 1000; i++) { b.move(); sleep(10); } } catch (InterruptedException exception) { } } private Ball b; }/** The canvas that draws the balls. */ class BallCanvas extends JPanel { /** Add a ball to the canvas. @param b the ball to add */ public void add(Ball b) { balls.add(b); } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; for (int i = 0; i < balls.size(); i++) { Ball b = (Ball)balls.get(i); b.draw(g2); } } private ArrayList balls = new ArrayList(); }/** A ball that moves and bounces off the edges of a component */ class Ball { /** Constructs a ball in the upper left corner @c the component in which the ball bounces */ public Ball(Component c) { canvas = c; } /** Draws the ball at its current position @param g2 the graphics context */ public void draw(Graphics2D g2) { g2.fill(new Ellipse2D.Double(x, y, XSIZE, YSIZE)); } /** Moves the ball to the next position, reversing direction if it hits one of the edges */ public void move() { x += dx; y += dy; if (x < 0) { x = 0; dx = -dx; } if (x + XSIZE >= canvas.getWidth()) { x = canvas.getWidth() - XSIZE; dx = -dx; } if (y < 0) { y = 0; dy = -dy; } if (y + YSIZE >= canvas.getHeight()) { y = canvas.getHeight() - YSIZE; dy = -dy; } canvas.repaint(); } private Component canvas; private static final int XSIZE = 15; private static final int YSIZE = 15; private int x = 0; private int y = 0; private int dx = 2; private int dy = 2; }
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;/**
Shows an animated bouncing ball running in a separate thread
*/
public class BounceThread
{
public static void main(String[] args)
{
JFrame frame = new BounceFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.show();
}
}/**
The frame with canvas and buttons.
*/
class BounceFrame extends JFrame
{
/**
Constructs the frame with the canvas for showing the
bouncing ball and Start and Close buttons
*/
public BounceFrame()
{
setSize(WIDTH, HEIGHT);
setTitle("BounceThread"); Container contentPane = getContentPane();
canvas = new BallCanvas();
contentPane.add(canvas, BorderLayout.CENTER);
JPanel buttonPanel = new JPanel();
addButton(buttonPanel, "Start",
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
addBall();
}
}); addButton(buttonPanel, "Close",
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
System.exit(0);
}
});
contentPane.add(buttonPanel, BorderLayout.SOUTH);
} /**
Adds a button to a container.
@param c the container
@param title the button title
@param listener the action listener for the button
*/
public void addButton(Container c, String title,
ActionListener listener)
{
JButton button = new JButton(title);
c.add(button);
button.addActionListener(listener);
} /**
Adds a bouncing ball to the canvas and starts a thread
to make it bounce
*/
public void addBall()
{
Ball b = new Ball(canvas);
canvas.add(b);
BallThread thread = new BallThread(b);
thread.start();
} private BallCanvas canvas;
public static final int WIDTH = 450;
public static final int HEIGHT = 350;
}/**
A thread that animates a bouncing ball.
*/
class BallThread extends Thread
{
/**
Constructs the thread.
@aBall the ball to bounce
*/
public BallThread(Ball aBall) { b = aBall; } public void run()
{
try
{
for (int i = 1; i <= 1000; i++)
{
b.move();
sleep(10);
}
}
catch (InterruptedException exception)
{
}
} private Ball b;
}/**
The canvas that draws the balls.
*/
class BallCanvas extends JPanel
{
/**
Add a ball to the canvas.
@param b the ball to add
*/
public void add(Ball b)
{
balls.add(b);
} public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
for (int i = 0; i < balls.size(); i++)
{
Ball b = (Ball)balls.get(i);
b.draw(g2);
}
} private ArrayList balls = new ArrayList();
}/**
A ball that moves and bounces off the edges of a
component
*/
class Ball
{
/**
Constructs a ball in the upper left corner
@c the component in which the ball bounces
*/
public Ball(Component c) { canvas = c; } /**
Draws the ball at its current position
@param g2 the graphics context
*/
public void draw(Graphics2D g2)
{
g2.fill(new Ellipse2D.Double(x, y, XSIZE, YSIZE));
} /**
Moves the ball to the next position, reversing direction
if it hits one of the edges
*/
public void move()
{
x += dx;
y += dy;
if (x < 0)
{
x = 0;
dx = -dx;
}
if (x + XSIZE >= canvas.getWidth())
{
x = canvas.getWidth() - XSIZE;
dx = -dx;
}
if (y < 0)
{
y = 0;
dy = -dy;
}
if (y + YSIZE >= canvas.getHeight())
{
y = canvas.getHeight() - YSIZE;
dy = -dy;
} canvas.repaint();
} private Component canvas;
private static final int XSIZE = 15;
private static final int YSIZE = 15;
private int x = 0;
private int y = 0;
private int dx = 2;
private int dy = 2;
}