Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new TestPane());
        frame.pack();
        frame.setVisible(true);
    }
}

class TestPane extends JPanel {
    int x = 0, y = 100, radius = 20, xDelta = 2;

    public TestPane() {
        Timer timer = new Timer(40, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                x += xDelta;
                if (x + (radius * 2) > getWidth()) {
                    x = getWidth() - (radius * 2);
                    xDelta *= -1;
                } else if (x < 0) {
                    x = 0;
                    xDelta *= -1;
                }
                repaint();
            }
        });
        timer.start();
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.RED);
        g.fillOval(x, y - radius, radius * 2, radius * 2);
    }
}