import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;

public class SwingPaintDemo {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI() {
        System.out.println("Created GUI on EDT? "+
        SwingUtilities.isEventDispatchThread());

        JFrame f = new JFrame("Swing Paint Demo");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new MyPanel());
        f.pack();
        f.setVisible(true);
    }
}


class MyPanel extends JPanel {

    Image  []  img;
    MediaTracker tracker;
    int     index = 0;
    int     maxImg;

    private void loadImages() {
        img = new Image[2];  // 2 images in animation
        tracker = new MediaTracker(this);
        System.out.println("Loading images...");
        maxImg = img.length - 1;

        try {
            // images loading
            img[0] = Toolkit.getDefaultToolkit().getImage("src/ill/frame0.gif");
            img[1] = Toolkit.getDefaultToolkit().getImage("src/ill/frame1.gif");

            tracker.addImage(img[0],0);
            tracker.addImage(img[1],1);
            tracker.waitForAll();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        AnimationThread at = new AnimationThread();
        at.delayedAnimation(this, 20);
        at.start();

        System.out.println("Started");
    }

    public MyPanel() {
        setBorder(BorderFactory.createLineBorder(Color.black));
        loadImages();
    }

    public Dimension getPreferredSize() {
        return new Dimension(800,800);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        // Draw Text
        g.drawString("This is my custom Panel!",10,20);

        if (img[0] != null) {
            g.drawImage(img[index],0,20,this);
            index = (index < maxImg) ? index + 1 : 0;
        }
    }

    public void animate() {
        repaint();
    }

    class AnimationThread extends Thread {
        MyPanel animationApplet;
        int delay;

        public void delayedAnimation(MyPanel a, int delay) {
            this.animationApplet = a;
            this.delay = delay;
        }

        public void run() {
            while (true) {
                try {
                    sleep(delay);
                    animationApplet.animate();
                }
                catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}