Running Game in a Java Applet

Question

I have written a small 2d scroller with the assistance of different snippets of code I have found on-line. The original package run as a JFrame application but I am trying to convert it into an applet. When I Run the program in Eclipse I do not receive any debugging errors just a blank applet viewer... I don't think I am missing anything from what I have read from different applet creation sources but maybe it is something very simple.

Frame class

package OurGame;

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

public class Frame extends JApplet {

public Frame() {
    JPanel frame = new JPanel();
    frame.add(new Board()); 
    // frame.setTitle("2D PLATFORMER");
    // frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(700,365);
    frame.setVisible(true);
    //frame.setLocationRelativeTo(null);
    //setContentPane(frame);
}
// public static void main(String[] args){
public void init() {
    new Frame();
}
 }

Ive commented out the containers that were only workable in Jframe.

Dude class

package OurGame;

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

public class Dude {
int x, dx, y,nx,nx2,left, dy;
Image still,jump,reverse;

ImageIcon s = new ImageIcon("redirect.png");
ImageIcon j= new ImageIcon("redirect.png");
ImageIcon l = new ImageIcon("redirect.png");

public Dude() {
    x = 75;
    left = 150;
    nx = 0;
    nx2= 685;
    y = 172;
    still = s.getImage();


}

public void move() {
    if (dx != -1){
        if (left + dx <= 150)
            left+=dx;
        else{
    x = x + dx;

    nx2= nx2+dx;
        nx = nx + dx;
}}
    else
{
    if (left+dx >0)
    left = left + dx;
}
    }

public int getX() {
    return x;
}

public int getnX() {
    return nx;
}

public int getnX2() {
    return nx2;
}

public int getdx() {
    return dx;
}

public Image getImage() {
    return still;
}

public void keyPressed(KeyEvent e) {
    int key = e.getKeyCode();
    if (key == KeyEvent.VK_LEFT)
    {       dx = -1;
    still = l.getImage();       }

    if (key == KeyEvent.VK_RIGHT)
        {dx = 1;
    still = s.getImage();   
        }

    if (key == KeyEvent.VK_UP)
        {dy = 1;
        still = j.getImage();
        }           }

public void keyReleased(KeyEvent e) {
    int key = e.getKeyCode();

    if (key == KeyEvent.VK_LEFT)
        dx = 0;

    if (key == KeyEvent.VK_RIGHT)
        dx = 0;

    if (key == KeyEvent.VK_UP)
        {dy = 0;
        still = s.getImage();}
        }
}

Board Class

package OurGame;

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

public class Board extends JPanel implements ActionListener, Runnable {
Dude p;
public Image img;
Timer time;
int v = 172;
Thread animator;

boolean a = false;
boolean done2 = false;

public Board() {
    p = new Dude();
    addKeyListener(new AL());
    setFocusable(true);
    ImageIcon i = new ImageIcon("redirect.jpg");
    img = i.getImage();
    time = new Timer(5, this);
    time.start();
}

public void actionPerformed(ActionEvent e) {
    p.move();
    repaint();
}

public void paint(Graphics g) {
    if (p.dy == 1 && done2 == false) {
        done2 = true;
        animator = new Thread(this);
        animator.start();
    }

    super.paint(g);
    Graphics2D g2d = (Graphics2D) g;

    if ((p.getX() - 590) % 2400 == 0)// p.getX() == 590 || p.getX() == 2990)
        p.nx = 0;
    if ((p.getX() - 1790) % 2400 == 0)// p.getX() == 1790 || p.getX() == 4190)
        p.nx2 = 0;

    g2d.drawImage(img, 685 - p.getnX2(), 0, null);
    if (p.getX() > 590) {
        g2d.drawImage(img, 685 - p.getnX(), 0, null);
    }
    g2d.drawImage(p.getImage(), p.left, v, null);

    if (p.getdx() == -1) {
        g2d.drawImage(img, 685 - p.getnX2(), 0, null);
        g2d.drawImage(p.getImage(), p.left, v, null);
    }
}

private class AL extends KeyAdapter {
    public void keyReleased(KeyEvent e) {
        p.keyReleased(e);
    }

    public void keyPressed(KeyEvent e) {
        p.keyPressed(e);
    }
}

boolean h = false;
boolean done = false;

public void cycle() {

    if (h == false)
        v--;
    if (v == 125)
        h = true;
    if (h == true && v <= 172) {
        v++;
        if (v == 172) {
            done = true;
        }
    }
}

public void run() {

    long beforeTime, timeDiff, sleep;

    beforeTime = System.currentTimeMillis();

    while (done == false) {

        cycle();

        timeDiff = System.currentTimeMillis() - beforeTime;
        sleep = 10 - timeDiff;

        if (sleep < 0)
            sleep = 2;
        try {
            Thread.sleep(sleep);
        } catch (InterruptedException e) {
            System.out.println("interrupted");
        }

        beforeTime = System.currentTimeMillis();
    }
    done = false;
    h = false;
    done2 = false;
}

}

I am a little stumbled after doing a fair amount of research. I am thinking Eclipse might not recognise that I have multiple class files but I kind of proved that theory wrong by writing a html page to display my applet that runs fine but is completely empty.

Answer 1

why is the applet viewer even in eclipse blank when running it..

At no point is anything added to the applet container. To add something to the applet would require overriding the applet init() method and calling add(new Board());. (That could also be done in the constructor, but it is more common to build an applet GUI within the init() method.)

---

Other Notes

paint(Graphics)

Since Board is a Swing class that is not a top-level container, custom painting should be done in the paintComponent(Graphics) method, rather than paint(Graphics).

Nomenclature

JPanel frame = new JPanel();

Wow! Poorly chosen attribute name. What do you call your JFrame instances, panel?

Application resources

ImageIcon s = new ImageIcon("redirect.png");

This will not work for an applet, and would not work for a deployed app. It is necessary to access images by URL. The Applet class has a specific method for loading images.

Remaining lines of constructor

JPanel frame = new JPanel();
frame.add(new Board()); 
frame.setSize(700,365);
frame.setVisible(true);

The first line of the constructor is not needed, the Board created in the next line can be added directly to the applet. That leaves two more lines not commented out.

frame.setSize(700,365);

The size of an applet should be set by the HTML.

frame.setVisible(true);

Anything added to a component that is visible will itself become visible. As such, this is also redundant.

Swing Timer

Since I pointed out so many faults in the code, just thought I should add that the animation seems to be done correctly - using a Swing Timer. :)