Why my Graphics2D isn't painting.

Hello, i would love to see if anybody can spot error in my code. I have been developing this code piece by piece and am sure everything is fine but it only prints white screen. Im sure i am saving and painting the images correctly.

Code:

---

package com.danger87.shoot;
Alien.java

package com.danger87.shoot;

import java.awt.Image;
import java.awt.Rectangle;

import javax.swing.ImageIcon;

public class Alien {

    private String craft = "alien.jpeg";

    private int x;
    private int y;
    private int width;
    private int height;
    private boolean visible;
    private Image image;

    public Alien(int x, int y) {
            System.out.println("Alien");
        ImageIcon ii = new ImageIcon(this.getClass().getResource(craft));
        image = ii.getImage();
        width = image.getWidth(null);
        height = image.getHeight(null);
        visible = true;
        this.x = x;
        this.y = y;
    }


    public void move() {
        if (x < 0)
            x = 400;
        x -= 1;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    public boolean isVisible() {
        return visible;
    }

    public void setVisible(Boolean visible) {
        this.visible = visible;
    }

    public Image getImage() {
        return image;
    }

    public Rectangle getBounds() {
        return new Rectangle(x, y, width, height);
    }
}

---

Code:

---

Board.java
package com.danger87.shoot;

import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.*;

import java.util.ArrayList;

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

public class Board extends JPanel implements ActionListener{
        /**
        *
        */
        private static final long serialVersionUID = 1L;
        private Timer timer;
        private Ufo ufo;
        private ArrayList<Alien>aliens;
        private boolean in_game;
        private int B_WIDTH;
        private int B_HEIGHT;
       
        private int[][] pos = {
                        {2380, 29}, {2500, 59}, {1380, 89},
                        {780, 109}, {580, 139}, {680, 239},
                        {790, 259}, {760, 50},  {790, 150},
                        {980, 209}, {560, 45},  {510,  70},
                        {930, 159}, {590, 80},  {530, 60},
                        {940, 59}, {990, 30},  {920, 200},
                        {900, 259}, {660, 50},  {540, 90},
                        {810, 220}, {860, 20},  {740, 180},
                        {820, 128}, {490, 170}, {700, 30},
        };
       
        public Board() {
                addKeyListener(new TAdapter());
                setFocusable(true);
                setBackground(Color.BLACK);
                setDoubleBuffered(true);
                in_game = true;
               
                setSize(400, 300);
               
                ufo = new Ufo();
               
                initAliens();
               
                timer = new Timer(5, this);
                timer.start();
        }
       
        public void addNotify() {
                super.addNotify();
                B_WIDTH = getWidth();
                B_HEIGHT = getHeight();
        }
       
        public void initAliens() {
                aliens = new ArrayList<Alien>();
               
                for (int i=0; i <pos.length; i++) {
                        aliens.add(new Alien(pos[i][0], pos[i][1]));
                }
        }
       
        public void paint (Graphics2D g) {
                super.paint(g);
               
                if (in_game) {
                        Graphics2D g2d = (Graphics2D)g;
                       
                        if (ufo.isVisible())
                                g2d.drawImage(ufo.getImage(), ufo.getX(), ufo.getY(), this);
                       
                        ArrayList<Missile> ms = ufo.getMissiles();
                       
                        for (int i = 0; i < ms.size(); i++) {
                                Missile m = (Missile)ms.get(i);
                                g2d.drawImage(m.getImage(),m.getX(),m.getY(),this);
                        }
                       
                        for (int i = 0; i < aliens.size(); i++) {
                                Alien a = (Alien)aliens.get(i);
                                if (a.isVisible())
                                        g2d.drawImage(a.getImage(),a.getX(),a.getY(),this);
                                }
                        g2d.setColor(Color.WHITE);
                        g2d.drawString("Aliens left: " + aliens.size(), 5, 15);
                       
                } else {
                        String msg = "Game Over";
                        Font small = new Font("Helvetica", Font.BOLD, 14);
                        FontMetrics metr = this.getFontMetrics(small);
                       
                        g.setColor(Color.white);
                        g.setFont(small);
                        g.drawString(msg, (B_WIDTH - metr.stringWidth(msg))/2,B_HEIGHT /2);
                }
               
                Toolkit.getDefaultToolkit().sync();
                g.dispose();
        }
       
        public void actionPerformed(ActionEvent e) {
               
                if (aliens.size() == 0) {
                        in_game = false;
                }
               
                ArrayList<Missile> ms = ufo.getMissiles();
               
                for (int i = 0; i < ms.size(); i++) {
                        Missile m = (Missile) ms.get(i);
                        if (m.isVisible())
                                m.move();
                        else ms.remove(i);
                }
                for (int i = 0; i < aliens.size(); i++) {
                        Alien a = (Alien) aliens.get(i);
                        if (a.isVisible())
                                a.move();
                        else aliens.remove(i);
                }
                ufo.move();
                checkCollison();
                repaint();
               
        }
       
        public void checkCollison() {
                Rectangle r3 = ufo.getBounds();
               
                for (int j = 0; j <aliens.size(); j++) {
                        Alien a = (Alien) aliens.get(j);
                        Rectangle r2 = a.getBounds();
                       
                        if(r3.intersects(r2)) {
                                ufo.setVisible(false);
                                a.setVisible(false);
                                in_game = false;
                        }
                }
               
                ArrayList<Missile> ms = ufo.getMissiles();
               
                for (int i = 0; i < ms.size(); i++) {
                        Missile m = (Missile) ms.get(i);
                       
                        Rectangle r1 = m.getBounds();
                       
                        for (int j = 0; j <aliens.size(); j++) {
                                Alien a = (Alien) aliens.get(j);
                                Rectangle r2 = a.getBounds();
                               
                                if (r1.intersects(r2)) {
                                        m.setVisible(false);
                                        a.setVisible(false);
                                }                       
                        }
                }
        }
        private class TAdapter extends KeyAdapter {
                public void keyReleased(KeyEvent e) {
                        ufo.keyReleased(e);
                }
                public void keyPressed(KeyEvent e) {
                        ufo.keyPressed(e);
                }
        }
}

---

Code:

---

Ufo.java
package com.danger87.shoot;

import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;

import java.util.ArrayList;

import javax.swing.ImageIcon;

public class Ufo {
       
        private String ufo = "ufo.png";
       
        private int dx,dy,x,y,width,height;
        private boolean visible;
        private Image image;
        private ArrayList<Missile> missiles;
       
        public Ufo() {
            System.out.println("UFO");
                ImageIcon ii = new ImageIcon(this.getClass().getResource(ufo));
                image = ii.getImage();
                width = image.getWidth(null);
                height = image.getHeight(null);
                missiles = new ArrayList<Missile>();
                visible = true;
                x = 40;
                y = 60;
        }
       
        public void move() {
                x += dx;
                y += dy;
               
                if (x < 1) {
                        x = 1;
                }
                       
                if (y < 1) {
                        y = 1;
                }
        }
               
        public int getX() {
                return x;
        }
       
        public int getY() {
                return y;
        }
       
        public Image getImage() {
                return image;
        }
       
        public ArrayList<Missile> getMissiles() {
                return missiles;
        }
       
        public void setVisible(boolean visible) {
                this.visible = visible;
        }
       
        public boolean isVisible() {
                return visible;
        }
       
        public Rectangle getBounds() {
                return new Rectangle (x, y, width, height);
        }
       
        public void keyPressed(KeyEvent e) {
                int key = e.getKeyCode();
               
                if (key == KeyEvent.VK_SPACE) {
                        fire();
                }
                if (key == KeyEvent.VK_LEFT) {
                        dx = -1;
                }
                if (key == KeyEvent.VK_RIGHT) {
                        dx = 1;
                }
                if (key == KeyEvent.VK_UP) {
                        dy = -1;
                }
                if (key == KeyEvent.VK_DOWN) {
                        dy = 1;
                }                   
        }
       
        public void fire() {
                missiles.add(new Missile(x + width, y + height/2));
        }
       
        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;
                }
                if (key == KeyEvent.VK_DOWN) {
                        dy = 0;
                }                   
        }
}

---

Code:

---

Missile.java
package com.danger87.shoot;

import java.awt.Image;
import java.awt.Rectangle;

import javax.swing.ImageIcon;

public class Missile {
       
        // missle can only move left and right.
        private int x,y;
        private Image image;
        boolean visible;
        private int width,height;
       
        private final int BOARD_WIDTH = 390;
        private final int MISSILE_SPEED = 2;
        private String missile = "missile.jpeg";
       
        public Missile(int x, int y) {
            System.out.println("Missile");
                ImageIcon ii = new ImageIcon(this.getClass().getResource(missile));
                image = ii.getImage();
                visible = true;
                this.x = x;
                this.y = y;
        }
       
        public Image getImage() {
                return image;
        }
       
        public int getX() {
                return x;
        }

        public int getY() {
                return y;
        }
       
        public boolean isVisible() {
                return visible;
        }
        public void setVisible(Boolean visible) {
                this.visible = visible;
        }
        public Rectangle getBounds() {
                return new Rectangle(x,y,width,height);
        }
       
        public void move() {
                // missile moves at constant speed if > than board length, disappear.
                x += MISSILE_SPEED;
                if (x > BOARD_WIDTH)
                        visible = false;
        }
}

---

Code:

---

Collision.java
package com.danger87.shoot;


import javax.swing.JFrame;

public class Collision extends JFrame {

    /**
        *
        */
        private static final long serialVersionUID = 1L;

        public Collision() {
        add(new Board());

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(400, 300);
        setLocationRelativeTo(null);
        setTitle("Collision");
        setResizable(false);
        setVisible(true);
    }

    public static void main(String[] args) {
        new Collision();
    }
}

---

There is no Missiles class.

I forgot .. Now updated. Sorry about that , still showing blank

There is no Alien Class either

That should do it.

It looks like this.getClass().getResource(ufo) is giving out a null Pointer for me.

Thats probably b.c you don't have the images along with the code. I have them all.

I think its not displaying anything because its never going to the paint method, even if you call repaint on the board.

I have no idea why it isn't calling paint method when i add(new Board()); I through a print statement inside constructor and you are right. It is not being called. How did you figure this out also?

I just used a debug breakpoint inside the paint method. It never stopped and went to debug mode.

Ok im pissed .. still looking for the bug. Maybe i need to become a become debugger, how did you learn?

I have already looked just your 2 classes so far, class Alien and class Board.

My suggestions (and questions) are:

1. in class Alien instead of using:

Code:

---

ImageIcon ii = new ImageIcon(this.getClass().getResource(craft));

---

I think it's better to use:

Code:

---

ImageIcon ii = new ImageIcon(craft);

---

2. in class Board

Code:

---

timer = new Timer(5, this);

---

Don't you think that this timer is too fast because number 5 in this constructor is equal to 0.005 second?

The 5ms should be fine. For shits and giggles i changed it and it still didn't affect anything. Also Your correct about the imageicon but that doesn't change anything either as i have written previous projects following that same syntax. The baffling part is that the paint() method isn't being called, NOT once ! I don't understand how this is possible when im adding the board to the JFrame in the Collision class.

In your class Board:

1. Your code:

Code:

---

public void paint (Graphics2D g) {
        super.paint(g);

---

I think that it should be Graphics instead of Graphics2D in this part of code.

Quote:

---

Also Your correct about the imageicon but that doesn't change anything either as i have written previous projects following that same syntax

---

I'm still looking your code sorry cause I'm slow.

Take your time and thanks. Maybe i should be a little slower when i code to avoid is mayheim !!:frusty:

Btw YOU WERE CORRECT ABOUT THE (Graphic2D g) instead of Graphics2D ;). Everything is now appearing .. I have to edit the collision bc i can shoot the missiles but it doesn't remove the aliens as planned haha YOU ARE A GOOD MAN SIR!

^That's great. Thanks for compliments.

Your welcome much! Another question. Im thinking of having a restart option, once the game over is displayed. I kinda have an idea but it seems dirty. Copy the constructor or Collision to another method and then call that method once game is over. There has to be a better way to do this ...