Develop Reference

Images no displaying in my java program

Recently i decided to start learning how to make 2D games With JAVA ( eclipse ) so i found a tutorial online that shows how to make superMari game with java, i wrote the same code he wrote and i followed step by step what he did, which wasn't a big thing to talk about, unfortunately he's code shows, after excuting, a window with two images in it while mine shows just the window with no images, i ensure you that i imported the two images and put them in one package to avoid all kind of problems but it still shows nothing.
my code has two classes, "main" and "Scene", here it is, hopefully someone will find a solution for me, thank you guys!
Main.java :
package AiMEUR.AMiN.jeu;
import javax.swing.JFrame;
public class Main {
public static Scene scene;
public static void main(String[] args) {
JFrame fenetre = new JFrame("Naruto in mario World!!");
fenetre.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fenetre.setSize(700, 360);
fenetre.setLocationRelativeTo(null);
fenetre.setResizable(false);
fenetre.setAlwaysOnTop(true);
scene = new Scene();
fenetre.setContentPane(scene);
fenetre.setVisible(true);
}
}
Scene.java :
package AiMEUR.AMiN.jeu;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class Scene extends JPanel{
private ImageIcon icoFond;
private Image imgFond1;
private ImageIcon icoMario;
private Image imgMario;
private int xFond1;
public Scene(){
super();
this.xFond1 = -50;
icoFond = new ImageIcon(getClass().getResource("/Images/fond.gif"));
this.imgFond1 = this.icoFond.getImage();
icoMario = new ImageIcon(getClass().getResource("/Images/1.png"));
this.imgMario = this.icoMario.getImage();
// paintComponent(this.getGraphics());
}
public void paintCompenent(Graphics g){
super.paintComponent(g);
Graphics g2 = (Graphics2D)g;
g2.drawImage(this.imgFond1, this.xFond1, 0, null);
g2.drawImage(imgMario, 300, 245, null);
}
}

You have not named the paintComponent method correctly, and therefore it is not being overridden.
The correct name is paintComponent not paintCompenent:
public class Example extends JPanel {
#Override
public void paintComponent(final Graphics g) {
super.paintComponent(g);
}
}

You can determine the loading status of an ImageIcon by doing something like this:
public Scene(){
super();
this.xFond1 = -50;
icoFond = new ImageIcon(getClass().getResource("/Images/fond.gif"));
int status = icoFond.getImageLoadStatus();
switch (status) {
case (MediaTracker.COMPLETE): {
System.out.println("icoFond image has successfully loaded");
}
case (MediaTracker.ERRORED): {
System.out.println("The icoFond image didn't load successfully");
// probably because the image isn't actually at "/Images/fond.gif"
}
}
this.imgFond1 = this.icoFond.getImage();
icoMario = new ImageIcon(getClass().getResource("/Images/1.png"));
this.imgMario = this.icoMario.getImage();
// paintComponent(this.getGraphics());
}

Why can't I getImage()?

I am having somewhat of an issue getting an image from another class. I have never had this problem before. Can someone please point me in the right direction.
package main;
import java.awt.Color;
import java.awt.DisplayMode;
import java.awt.Graphics;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
public class Main extends JFrame {
public static Character character;
static GraphicsEnvironment graphicsEnvironment;
static GraphicsDevice graphicsDevice;
static DisplayMode displayMode;
private Image i;
public static void main(String[] args) {
displayMode = new DisplayMode(1280, 720, 16, DisplayMode.REFRESH_RATE_UNKNOWN);
graphicsEnvironment = GraphicsEnvironment.getLocalGraphicsEnvironment();
graphicsDevice = graphicsEnvironment.getDefaultScreenDevice();
Main m = new Main();
m.run();
}
public void run() {
setUndecorated(true);
setResizable(false);
graphicsDevice.setFullScreenWindow(this);
try {
graphicsDevice.setDisplayMode(displayMode);
} catch (Exception e) {
}
}
public void paint(Graphics g) {
g.setColor(Color.cyan);
g.fillRect(0, 0, displayMode.getWidth(), displayMode.getHeight());
i = character.getImage();
g.drawImage(i, 100, 100, this);
}
}
package main;
import java.awt.Image;
import javax.swing.ImageIcon;
public class Character {
private Image i;
public Image getImage() {
i = new ImageIcon(this.getClass().getResource("/raw/images/player1.png")).getImage();
return i;
}
}
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at main.Main.paint(Main.java:52)
It says that the error is i = character.getImage();
I have done this plenty of times when making applets, this if the first time I am trying a fullscreen game

Remember to think about what the compiler is telling you.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
A NullPointerException means a reference variable hasn't been initialized (or is == null, for that matter). In your case, that means to debug it you'll have to check both i and character. If it was the image you were trying to return, the stacktrace would go one deeper.
Since you are initializing i, look back up at character. You never set character to anything, which means you can't use it in any declarations.
So, your solution is to do character = new Character(); in run() or main(String[] args),
or you can set getImage() to static, and say i = Character.getImage();.

Change the method declaration to
public static Image getImage(){/*your code here */}
And the statement to call that method make sure that the first letter is C in uppercase not c. as in Character.getImage()

Multiple instances of the same animated GIF in a Canvas (Java)

So I'm making a game where you can put bombs on the location of your character. Each bomb is associated with a GIF image when the bomb is displayed and eventually go BOOM (think about Bomberman).
The problem was, when i tried to paint more than one bomb on the screen, it was painted from the last frame of the GIF. Investigating, I found the method image.flush() to reset the GIF cicle but now the problem is that every time I paint a second bomb on the screen, the GIF cycle is reset for all previously bombs on screen.
Here is my constructor for each bomb:
public Tnt(int x, int y){
this.x = x;
this.y = y;
ImageIcon ii = new ImageIcon("src/main/resources/modelObjects/tnt.gif");
image = ii.getImage();
image.flush();
}
Every bomb i create enters an ArrayList (listTnt) and is removed after 6 secs, so i only paint the bombs already active.
Here is my method for drawing:
public void draw(Graphics2D g2d, JPanel board){
for(Tnt tnt: listTnt){
g2d.drawImage(tnt.getImage(), tnt.getX(), tnt.getY(), board);
}
}
EDIT: Seems that the problem was ImageIcon, since it reuses the image using Toolkit.getImage. Instead, Toolkit.createImage create a not reusable image.
Here is my new constructor for Tnt that worked perfectly:
public Tnt(int x, int y){
this.x = x;
this.y = y;
Toolkit t = Toolkit.getDefaultToolkit ();
image = t.createImage("src/main/resources/modelObjects/tnt.gif");
}
I dont even need image.flush() now. Thank you all.

The underlying Image is being reused amongst each ImageIcon.
Judging by the OpenJDK source code, it appears to be due to the fact that each simply requests the Image via Toolkit.getImage.
This method has a nifty caveat, however, which explains the issue at hand:
The underlying toolkit attempts to resolve multiple requests with the same filename to the same returned Image.
Instead, you should skip the ImageIcon step completely (since it's inappropriate to be using a Swing class unnecessarily in the first place), and instead call Toolkit.createImage, which states in the documentation:
The returned Image is a new object which will not be shared with any other caller of this method or its getImage variant.
Good luck.

As I did not know how to solve this, I tried #super_ solution and it works quite nicely. I share the code for anyone who wants an example. +1 to him
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class TestAnimatedGif {
private static final int IMAGE_COUNT = 9;
protected void initUI() {
JFrame frame = new JFrame(TestAnimatedGif.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JPanel panel = new JPanel();
frame.add(panel);
frame.setSize(600, 400);
frame.setVisible(true);
final Timer t = new Timer(1000, null);
t.addActionListener(new ActionListener() {
int count = 0;
#Override
public void actionPerformed(ActionEvent e) {
if (count < IMAGE_COUNT) {
try {
JLabel image = new JLabel(new ImageIcon(Toolkit.getDefaultToolkit().createImage(
new URL("http://www.sitevip.net/gifs/bomba/BOMB-B_animado.gif"))));
panel.add(image);
count++;
panel.revalidate();
panel.repaint();
System.err.println("image added");
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} else {
t.stop();
}
}
});
t.start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestAnimatedGif().initUI();
}
});
}
}

JSpinner not reacting on MouseWheelEvent on Windows

This is getting me quite confused:
I have a small application that uses a JSpinner for numeric values. I added a MouseAdapter to it, setting the value depending on the resulting event's getScrollAmount() and getWheelRotation().
Everything is working quite fine as long as the application is run on linux (Debian Wheezy, Oracle JDK 1.6.0_32). That is, scrolling the mouse wheel while the JSpinner has focus works just fine (using GTK LookAndFeel).
Testing the software on Microsoft Windows exposed a different behavior:
The JSpinner will not react on mouse wheel movement. LookAndFeels don't seem to be a problem here, as i already tried MetalLookAndFeel on both Linux and Windows.
Any suggestions on how to get this JSpinner reacting on MouseWheelEvents on both OSes?
Thank you.

Hmm im not sure what could be wrong, but here is code designed on windows 7 and it works fine so maybe try it out on yours and see where the code is different:
import java.awt.Container;
import java.awt.EventQueue;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
/**
*
* #author David
*/
public class JSpinnerMouse extends JFrame {
private JSpinner jspinner;
public JSpinnerMouse() {
createAndShowUI();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
// If Nimbus is not available, you can set the GUI to another look and feel.
}
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JSpinnerMouse jSpinnerMouse = new JSpinnerMouse();
}
});
}
private void createAndShowUI() {
setTitle("JSpinner using mouse wheel");
setSize(300, 300);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
addComponentsToContentPane(getContentPane());
addListeners();
setVisible(true);
}
private void addComponentsToContentPane(Container contentPane) {
jspinner = new JSpinner();
contentPane.add(jspinner);
}
private void addListeners() {
this.addMouseWheelListener(new MouseWheelListener() {
#Override
public void mouseWheelMoved(MouseWheelEvent mwe) {
if (MouseWheelEvent.WHEEL_UNIT_SCROLL == mwe.getScrollType()) {
int value = (int) jspinner.getValue();
if (mwe.getWheelRotation() == -1) {//up
jspinner.setValue(value + 1);
} else {//down
jspinner.setValue(value - 1);
}
}
}
});
}
}
Also to mention, I could not find the getDirection() method in the MouseWheelEvent like you said you are using so i used the getUnitsToScroll() which will return either a positive or negative value depending on the direction. Maybe this is whats causing the trouble. Where did you find a getDirection() method in the MouseWheelEvent Class?

Illegal State Exception when creating new Bufferstrategy

When I am trying to figure out how to use bufferstrategies, and overall just improving how I write my code and cleaning things up. When I run the following code, I get an error when I "createBufferStrategy(3)"
package Game1Test;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.io.IOException;
import javax.swing.*;
public class Base extends Canvas implements Runnable{
private static final long serialVersionUID = 1L;
private boolean running = false;
int ticks = 0;
public Base(JFrame f) {
setSize(f.getWidth(),f.getHeight());
start();
}
public void start(){
running = true;
new Thread(this).start();
}
public void stop(){
}
public void run(){
while(running){
ticks++;
System.out.println(ticks);
render();
try {
Thread.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void render(){
BufferStrategy bs = getBufferStrategy();
Graphics g;
if(bs == null){
createBufferStrategy(3);
requestFocus();
return;
}
bs.show();
}
}
The Base is then added with:
package Game1Test;
import java.awt.*;
import javax.swing.JFrame;
public class Screen extends JFrame{
public final int GAME_WIDTH = 400;
public final int GAME_HEIGHT = 400;
public Dimension gameDim = new Dimension(GAME_WIDTH,GAME_HEIGHT);
final String gameName = "Test";
public Screen(){
setSize(gameDim);
setTitle(gameName);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setLayout(new GridLayout());
setVisible(true);
setLocationRelativeTo(null);
}
public static void main(String[] args){
Screen s = new Screen();
s.add(new Base(s));
}
}
I get the following error:
Exception in thread "Thread-2" java.lang.IllegalStateException: Component must have a valid peer
at java.awt.Component$FlipBufferStrategy.createBuffers(Unknown Source)
at java.awt.Component$FlipBufferStrategy.<init>(Unknown Source)
at java.awt.Component$FlipSubRegionBufferStrategy.<init>(Unknown Source)
at java.awt.Component.createBufferStrategy(Unknown Source)
at java.awt.Canvas.createBufferStrategy(Unknown Source)
at java.awt.Component.createBufferStrategy(Unknown Source)
at java.awt.Canvas.createBufferStrategy(Unknown Source)
at Game1Test.Base.render(Base.java:46)
at Game1Test.Base.run(Base.java:33)
at java.lang.Thread.run(Unknown Source)
Can someone please tell me why this is happening? and maybe a solution to this problem?
Thanks

Taking a look at the API, this exception is thrown if the component is not displayable. In this case, that's when Canvas.peer is null. Taking a look at the peer field reveals that
The peer is set when the Component is added to a
container that also is a peer
Since you are starting the update thread from your component's constructor, render could be called before your component is ever added to another container which would mean the peer is null, and then an IllegalStateException would be thrown.

In my experience with this error and with the code you writing you missing a frame function.
Add where your frames are (ex: frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);) and add the function frame.add(game);
In this example, mine is Display game = new Display(); but depending on what your variable for the new display is, it might vary.

I had exactly the same exception, but i found out that it was because my JFrame visibility was accidentally set to false.
so puting in setVisible(true); fixed it.