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());
}

Problems with animation on a png image

Hello all So I'm making progress on my animation program but I'm running into a problem where my alien.png isn't showing up in the jframe. I have the alien.png in the same folder as this animation demo.java so I'm not sure why its not finding the alien.png. Any help would be appreciated
package animationdemo;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class AnimationDemo extends JFrame {
Image alien;
public AnimationDemo() {
alien = Toolkit.getDefaultToolkit().getImage("alien.png");
MovingMessagePanel messagePannel = new MovingMessagePanel();
messagePannel.alien = this.alien;
Timer timer = new Timer(50, messagePannel);
timer.start();
this.add(messagePannel);
}
public static void main(String[] args) {
AnimationDemo frame = new AnimationDemo();
frame.setTitle("Project 10");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
frame.setVisible(true);
}
}
class MovingMessagePanel extends JPanel implements ActionListener {
public int xCoordinate = 20;
public int yCoordinate = 20;
public int xDir=5;
public int yDir=5;
public Image alien;
public void actionPerformed(ActionEvent e) {
repaint();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (xCoordinate > getWidth()) xDir*=-1;
if (yCoordinate > getHeight()) yDir*=-1;
if (xCoordinate <0) xDir*=-1;
if (yCoordinate <0) yDir*=-1;
xCoordinate += xDir;
yCoordinate += yDir;
g.drawImage(alien,xCoordinate,yCoordinate,this);
}
}

Let's look at the code lines:
package animationdemo; // this one!
import java.awt.Graphics;
// ..
public class AnimationDemo extends JFrame {
Image alien;
public AnimationDemo() {
alien = Toolkit.getDefaultToolkit().getImage("alien.png"); // & this one!
That last line is effectively trying to load a File from the 'current directory'.
But the image probably won't be accessible as a File any longer. Application resources will become embedded resources by the time of deployment, so it is wise to start accessing them as if they were, right now. An embedded-resource must be accessed by URL rather than file. See the info. page for embedded resource for how to form the URL.
Note given the first highlit line, the best path for finding the resource would presumably be:
..getResource("/animationdemo/alien.png")
Note also that the getResource method is case sensitive, so ..
..getResource("/animationdemo/alien.PNG")
.. won't find the lower case version, nor vice-versa.
As an aside, I did a check of my 'missing image' theory by making this small change to the source above:
alien = new BufferedImage(40, 40, BufferedImage.TYPE_INT_RGB);
//Toolkit.getDefaultToolkit().getImage("alien.png");
Given I saw an animated black square, it supports the major problem is that the image is not being found. The code still has a few other aspects that should be tweaked, but it is basically going in the right direction.

display a sequence of images by a thread in java

Here is what I'm trying to do - making long story short:
Building a window (will call him MainWindow) with buttons at top and a picture on the center of it. I want to give the user the options to chose what to do (the buttons) while changing the center picture every couple of sec. Part of the options given to the user is 'pause' and 'resume' - controlling the sequence.
Basically trying to update GUI (MainWindow) by a Thread. This Thread will RUN WHILE boolean 'playSequence' will be true.
Can someone explain why can't I get it to work..
Here is the Code:
package SpecializedControls;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingWorker;
import DataEntities.SgiImage;
public class SgiImagePanel extends JPanel implements Runnable {
private List<SgiImage> seqImageList;
private JLabel lastImage;
private boolean playSequence;
public SgiImagePanel (){}
public SgiImagePanel (List<SgiImage> sequenceList)
{
seqImageList = sequenceList ;
}
#Override
public void run() {
// TODO Auto-generated method stub
while(playSequence)
{
for (SgiImage image : seqImageList)
{
display(image);
try {
Thread.sleep(3000);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public void display(SgiImage image)
{
reset();
JLabel picLabel = new JLabel(new ImageIcon(image.getImage()));
add(picLabel);
lastImage = picLabel;
}
public void display(List<SgiImage> sequenceList)
{
if(sequenceList==null)
return;
playSequence = true;
SgiImagePanel seq = new SgiImagePanel(sequenceList);
Thread thread = new Thread(seq);
thread.start();
}
public void reset(){
if (lastImage != null)
{
remove(lastImage);
lastImage = null;
}
}
public void pause() {
playSequence = false;
}
public void resume(){
playSequence = true;
}
}

Don't directly use Threads for this. There's no need, and it carries risk if you call code in a background thread that changes Swing state without care.
Use a Swing Timer for your animation loop.
Display your images as ImageIcons in a JLabel.
One of the main problems with your code is that you keep creating a bunch of new JLabels needlessly and dangerously. One JLabel is all you need and all you want. So instead, create the image displaying JLabel just once and then swap icons via its setIcon(...) method.
Read in your image Icon just once, and save it in a variable or collection.
You can easily pause a Swing Timer by simply calling its stop() method, and can restart it just as easily by calling start().

Try to load the image with this code:
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
public class ImagePanel extends JPanel{
private BufferedImage image;
public ImagePanel() {
try {
image = ImageIO.read(new File("image name and path"));
} catch (IOException ex) {
// handle exception...
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, null); // see javadoc for more info on the parameters
}
}

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();
}
});
}
}

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.