import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;

public class Rebotador2 extends Applet implements ActionListener {

private Button iniciar;

public void init() {
iniciar = new Button("Iniciar");
add(iniciar);
iniciar.addActionListener(this);
}
public void actionPerformed (ActionEvent event) {
if (event.getSource() == iniciar) {
Graphics g = getGraphics();
Pelota2 pelota = new Pelota2(g);
pelota.start();
}
}

class Pelota2 extends Thread {
private Graphics g;
private int x = 7, xCambio = 7;
private int y = 0, yCambio = 2;
private int diametro = 10;
private int rectIzqX = 0, rectDerX = 100;
private int rectSupY = 0, rectInfY = 100;


public Pelota2 (Graphics graficos) {
g = graficos;
}

public void run() {
g.drawRect (rectIzqX, rectSupY, rectDerX - rectIzqX+10, rectInfY - rectSupY+10);



for (int n = 1; n < 1000; n++) {
g.setColor(Color.white);
g.fillOval(x, y, diametro, diametro);
if (x + xCambio <= rectIzqX)
xCambio = -xCambio;
if (x + xCambio >= rectDerX)
xCambio = -xCambio;


if (y + yCambio <= rectSupY)
yCambio = -yCambio;
if (y + yCambio >= rectInfY)
yCambio = -yCambio;

x = x + xCambio;
y = y + yCambio;


g.setColor(Color.red);
g.fillOval(x, y, diametro, diametro);

try {
Thread.sleep(50);
}
catch (InterruptedException e) {
System.err.println("Excepcion de inactividad");
}
}
}
}
}