In my first program repaint work corectly, but in the second program i have a problem with it.
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class repaint1 {
public static void main(String[] args) {
JFrame win = new JFrame("");
test1 content = new test1();
win.setContentPane(content);
win.setSize(600, 400);
win.setLocation(100, 100);
win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
win.setResizable(false);
win.setVisible(true);
content.function();
}
}
class test1 extends JPanel {
private BufferedImage img;
public int x = 50;
public int y = 50;
public test1() {
}
public void function() {
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
for (int i = 50; i < 150; i++) {
x = i;
y = i;
try {
Thread.sleep(10);
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
repaint();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
try {
img = ImageIO.read(new File("images.jpg"));
g.drawImage(img, x, y, null);
} catch (IOException ex) {
// handle exception...
}
}
}
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class repaint2 {
public static void main(String[] args) {
JFrame f = new JFrame("JFrame");
test2 content = new test2();
f.setContentPane(content);
f.setSize(600, 400);
f.setLocation(100, 100);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setResizable(false);
f.setVisible(true);
}
}
class test2 extends JPanel {
private BufferedImage img;
public int x = 50;
public int y = 50;
public test2() {
JButton button = new JButton("Start !");
button.setBounds(458, 24, 122, 23);
button.setVisible(true);
add(button);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// Execute when button is pressed
function();
}
});
}
public void function() {
for (int i = 50; i < 150; i++) {
x = i;
y = i;
repaint();
try {
Thread.sleep(10);
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
try {
img = ImageIO.read(new File("images.jpg"));
g.drawImage(img, x, y, null);
} catch (IOException ex) {
// handle exception...
}
}
}
In the first case the function() method is invoked from the main Thread, so when you invoke sleep() this Thread sleeps, which does not affect painting of the GUI.
In the second case your function() method is invoked from the ActionListener. All code executed from a listener is invoked on the Event Dispatch Thread (EDT), which is responsible for repainting the GUI. When you tell the Thread to sleep() the EDT sleeps, so it can't repaint the GUI until the loop finishes executing.
In your ActionListener code you need to start a separate Thread. One way to do this is to use a SwingWorker.
Read the section from the Swing tutorial on Concurrency for more information.
To move your image every time you need to use implements Runnable in your JPanel class. Here this class (MyJPanleClass) will behave like both as JPanel and Thread.
public class MyJPanleClass extends JPanel implements Runnable{
public MyJPanleClass(){
//constractor
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
//do your staff with g
}
#Override
public void run(){
repaint();
}
}
To execute it from main class just write this code:
MyJPnaleClass jp=new MyJPanelClass();
Thread t1=new Thread(jp);
t1.start();//this will call run class
try{
t1.join();//running the thread until it finish.
}catch(Exception ex){}
If you don't have any idea about thread just follow the link to learn it: Thread in java tutorial
Related
I have a for loop that iterates within an actionPerformed method. Basically, I have a car game. I have a panel where car images travel from side to side in a JPanel. I am trying to have the cars stop at the finish line (I am doing that by sleeping when the image reaches a certain x value) display the race results, leave the screen and race again. I need to do that four times until we have a winner.
private class RaceDisplay extends JPanel implements ActionListener{
private Image img1,img2;
private int velX1,velX2;
private int x1,x2;
private Timer tm;
private JTextArea text1 = new JTextArea();
public RaceDisplay(){
tm = new Timer(30,this);
x1=0;
x2=0;
velX1=2;
velX2 =2;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
ImageIcon car1 = new ImageIcon("...");
ImageIcon car2 = new ImageIcon("...");
img1 = car1.getImage();
img2 = car2.getImage();
g.drawImage(img1,x1,100,null);
g.drawImage(img2,x2,200,null);
tm.start();
}
public void actionPerformed(ActionEvent e) {
x1=x1+velX1;
velX2= x2+velX2;
repaint();
for(int count = 0;count<=4;count++){//<-----loop with issues.
if(count == 1){
text1.setText(result());
}
if(x1>=650 && x2>=650){ //does this when both cars reach the line
velX1=0;
velX2=0;
try {
Thread.sleep(2500);
} catch (InterruptedException ex) {
Logger.getLogger(Display.class.getName()).log(Level.SEVERE, null, ex);
}
x1=0;
x2=0;
repaint();
velX1= x1+velX1;
velX2= x2+velX2;
}
}
repaint();
}
I created the for loop that should check the if statements when it reaches the last counter it displays the winner(method for winner in the code). I was expecting the images to travel from side to four times and display the results four times.
But it only display anything if i set the if(counter==1) to (counter==0).
Can anyone help?
Thanks.
Don't call tm.start(); from within the paintComponent method, this is just asking for trouble. Painting may occur for any number of reasons, many of which you don't control or have knowledge about
Don't call Thread.sleep from within the context of the Event Dispatching Thread. This isn't stopping the Timer, but is prevent the EDT from processing the Event Queue, which includes things like repaint events and timer events...
Instead, once you've detected that a car has passed the finish line, you can either, stop updating that car's position and/or stop the Timer
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Map<BufferedImage, Rectangle> carBounds;
private BufferedImage blueCar;
private BufferedImage redCar;
public TestPane() {
carBounds = new HashMap<>(25);
try {
blueCar = ImageIO.read(getClass().getResource("/BlueCar.png"));
redCar = ImageIO.read(getClass().getResource("/RedCar.png"));
int x = 0;
int y = (200 / 2 ) - blueCar.getHeight();
carBounds.put(blueCar, new Rectangle(x, y, blueCar.getWidth(), blueCar.getHeight()));
y = (200 / 2);
carBounds.put(redCar, new Rectangle(x, y, redCar.getWidth(), redCar.getHeight()));
} catch (IOException ex) {
ex.printStackTrace();
}
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
for (BufferedImage img : carBounds.keySet()) {
Rectangle bounds = carBounds.get(img);
int xDelta = (int)Math.round((Math.random() * 7) + 1);
bounds.x += xDelta;
if (bounds.x + bounds.width > getWidth()) {
bounds.x = getWidth() - bounds.width;
((Timer)e.getSource()).stop();
}
}
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
for (BufferedImage img : carBounds.keySet()) {
Rectangle bounds = carBounds.get(img);
g2d.drawImage(img, bounds.x, bounds.y, this);
}
g2d.dispose();
}
}
}
Take a closer look at Concurrency in Swing for more details
I am trying to simply rotate an image in a for loop like so:
class MyCanvas extends JComponent {
AffineTransform identity = new AffineTransform();
Image arrow;
Double angle = -180.0;
public void spin() {
angle += 10.0;
for(int i = 0; i < 10; i++) {
repaint();
System.out.println(i);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
arrow = Toolkit.getDefaultToolkit().getImage("red-arrow-right-th.png");
// Rotate + translate
AffineTransform trans = new AffineTransform();
trans.setTransform(identity);
trans.translate(getWidth()/2, getHeight()/2);
trans.rotate(Math.toRadians(angle));
System.out.println(trans);
g2.drawImage(arrow, trans, this);
g2.finalize();
}
}
However when I run call spin() in main, it appears to apply only a single rotation, whilst still printing out the loop correctly. What am I overlooking something?
I've transformed your code using the recommendation of MadProgrammer:
Don't override paint, override paintComponent.
Call super.paint before performing any custom painting,
Never call finalize on anything and especially not on objects you didn't create yourself.
Use a Swing Timer
Note the following
A qualified this is used to access the ImageRotationView instance from the ActionListener inner class.
AffineTransform.getRotateInstance returns a transform that rotates coordinates around an anchor point.
Speed can be optimized but it works correctly like this.
This class works as a standalone application
A file named dice.png should be present in the base directory.
.
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.Timer;
public class ImageRotationFrame {
public static void main(String[] args) {
new ImageRotationFrame();
}
public ImageRotationFrame() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Testing");
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new ImageRotationComponent());
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private class ImageRotationComponent extends JComponent {
Image arrow;
double angle = 0.0;
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
angle += 0.4;
AffineTransform trans = AffineTransform.getRotateInstance(angle, getWidth() / 2, getHeight() / 2);
((Graphics2D) g).drawImage(arrow, trans, this);
}
public ImageRotationComponent() {
try {
arrow = ImageIO.read(new File("dice.png"));
} catch (IOException e) {
e.printStackTrace();
}
int delay = 500; //milliseconds
ActionListener taskPerformer = new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
ImageRotationComponent.this.repaint();
}
};
new Timer(delay, taskPerformer).start();
}
}
}
I want to take a print screen of what is behind the JFrame, without the JFrame itself. The way I tried was to close the window, wait for a while so it fully closes, then take the print screen and then open it again. The current method is not good for what I need since I need to do it more frequently and waiting for the window to close is too much time. Also, I don't want to close the window for that.
Here is my current code:
public class Offscreen {
private static BufferedImage img;
public static void main(String[] main)
throws AWTException, InterruptedException {
JFrame frame = new JFrame() {
#Override
public void paint(Graphics g) {
if (img != null)
// draw print screen
g.drawImage(img, 0, 0, null);
}
};
frame.setSize(500, 500);
frame.setLocation(700, 0);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setVisible(false);
Thread.sleep(200);
// take the picture
Robot r = new Robot();
img = r.createScreenCapture(frame.getBounds());
// show the source again
frame.setVisible(true);
// print on destiny
frame.repaint();
}
}
"Assuming" you only want to capture the area behind the active frame (and as you say, without the frame), then something like..
import java.awt.AWTException;
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.image.BufferedImage;
import java.lang.reflect.InvocationTargetException;
import java.util.concurrent.ExecutionException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class PrintScreen01 {
public static void main(String[] args) {
new PrintScreen01();
}
private Timer timer;
public PrintScreen01() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
final PrintPane printPane = new PrintPane();
final JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(printPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.addComponentListener(new ComponentAdapter() {
#Override
public void componentMoved(ComponentEvent e) {
timer.restart();
}
#Override
public void componentResized(ComponentEvent e) {
timer.restart();
}
});
timer = new Timer(250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (frame.isVisible()) {
takeSnapShot(frame, printPane);
}
}
});
timer.setRepeats(false);
frame.setVisible(true);
// takeSnapShot(frame, printPane);
}
});
}
public void takeSnapShot(JFrame frame, PrintPane pane) {
Rectangle bounds = new Rectangle(pane.getLocationOnScreen(), pane.getSize());
frame.setVisible(false);
new SnapShotWorker(frame, pane, bounds).execute();
}
public class SnapShotWorker extends SwingWorker<BufferedImage, BufferedImage> {
private JFrame frame;
private PrintPane pane;
private Rectangle captureBounds;
public SnapShotWorker(JFrame frame, PrintPane pane, Rectangle bounds) {
this.frame = frame;
this.pane = pane;
captureBounds = bounds;
}
#Override
protected BufferedImage doInBackground() throws Exception {
Thread.sleep(125);
BufferedImage snapShot = null;
try {
Robot bot = new Robot();
snapShot = bot.createScreenCapture(captureBounds);
} catch (AWTException ex) {
ex.printStackTrace();
}
Thread.sleep(125);
return snapShot;
}
#Override
protected void done() {
try {
BufferedImage snapShot = get();
pane.setSnapShot(snapShot);
frame.setVisible(true);
} catch (InterruptedException ex) {
ex.printStackTrace();
} catch (ExecutionException ex) {
ex.printStackTrace();
}
}
}
public class PrintPane extends JPanel {
private BufferedImage background;
public PrintPane() {
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
public void setSnapShot(BufferedImage img) {
background = img;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (background != null) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));
g2d.drawImage(background, 0, 0, this);
g2d.dispose();
}
}
}
}
May help...
Now, I had some issues with the timing of Robot, it would seem that part of the operation is threaded in some way, meaning that unless you got the timing of the frame changing between invisible and visible "just" right, you would actually recapture the frame...annoying...
To try and fix this, and reduce the amount of times I tried capturing the screen, I employed a javax.swing.Timer (to reduce the capture attempts) and a SwingWorker to control the actual snapshot process, taking it out of the Event Dispatching Thread, there by ensuring (to some degree) that the window will be invisible.
I also added some additional lag to ensure that the frame was off the screen long enough to prevent it been capture by the snapshot...
I've just moved over from Pygame so Java 2D in an applet is a little new to me, especially when it comes to repainting the screen. In pygame you can simply do display.fill([1,1,1]) but how do I do this in an applet in Java? I understand the use of repaint() but that doesn't clear the screen - any moving object is not 'removed' from the screen so you just get a long line of painted circles.
Here's my code that I've been testing with:
package circles;
import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Random;
public class circles extends Applet implements Runnable {
private static final long serialVersionUID = -6945236773451552299L;
static Random r = new Random();
String msg = "Click to play!";
static int w = 800, h = 800;
int[] txtPos = { (w/2)-50,(h/2)-50 };
int[] radiusRange = { 5,25 };
int[] circles;
static int[] posRange;
int x = 0, y = 0;
int radius = 0;
int cursorRadius = 10;
boolean game = false;
public static int[] pos() {
int side = r.nextInt(5-1)+1;
switch(side) {
case 1:
posRange = new int[]{ 1,r.nextInt(w),r.nextInt((h+40)-h)+h,r.nextInt(270-90)+90 };
break;
case 2:
posRange = new int[]{ 2,r.nextInt((w+40)-w)+w,r.nextInt(h),r.nextInt(270-90)+90 };
break;
case 3:
posRange = new int[]{ 3,r.nextInt(w),r.nextInt(40)-40,r.nextInt(180) };
break;
case 4:
posRange = new int[]{ 4,r.nextInt(40)-40,r.nextInt(h),r.nextInt(180) };
break;
}
System.out.println(side);
return posRange;
}
public void start() {
setSize(500,500);
setBackground(Color.BLACK);
new Thread(this).start();
}
public void run() {
}
public void update(Graphics g) {
paint(g);
}
public void paint(Graphics e) {
Graphics2D g = (Graphics2D) e;
if(System.currentTimeMillis()%113==0) {
x+=1;
y+=1;
}
g.setColor(Color.BLUE);
g.fillOval(x,y,20,20);
repaint();
}
}
You need to call super.paint(g); in your paint method, as to not leave paint artifacts.
Never call repaint() from inside the paint method
Don't explicitly call paint, as you do in update(), when you mean to call reapaint()
just update the x and y values from inside the update() method, then call repaint()
You don't need to take a Graphics argument in update()
You need to call update() somewhere repeatedly in a loop, as it updates the x and y and reapint()s
If your class is going to be a Runnable, then you should put some code in the run() method. That's probably where you should have your loop
import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
public class circles extends Applet implements Runnable {
int x = 0, y = 0;
public void start() {
setSize(500, 500);
setBackground(Color.BLACK);
new Thread(this).start();
}
public void run() {
while (true) {
try {
update();
Thread.sleep(50);
} catch (InterruptedException ex) {
}
}
}
public void update() {
x += 5;
y += 6;
repaint();
}
public void paint(Graphics e) {
super.paint(e);
Graphics2D g = (Graphics2D) e;
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
}
Side Notes
Why use Applets in the first place. If you must, why use AWT Applet and not Swing JApplet? Time for an upgrade.
Here's how I'd redo the whole thing in Swing, using a Swing Timer instead of a loop and Thread.sleep, as you should be doing.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Circle extends JPanel{
private static final int D_W = 500;
private static final int D_H = 500;
int x = 0;
int y = 0;
public Circle() {
setBackground(Color.BLACK);
Timer timer = new Timer(50, new ActionListener(){
public void actionPerformed(ActionEvent e) {
x += 5;
y += 5;
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.add(new Circle());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
See How to use Swing Timers
See Create GUIs with Swing
Here's more advanced example for you to look at and ponder.
UPDATE
"Problem is, that's a JPANEL application. I specifically want to make an applet easily usable on a web page. "
You can still use it. Just use the JPanel. Take out the main method, and instead of Applet, use a JApplet and just add the JPanel to your applet. Easy as that.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.Timer;
public class CircleApplet extends JApplet {
#Override
public void init() {
add(new Circle());
}
public class Circle extends JPanel {
private static final int D_W = 500;
private static final int D_H = 500;
int x = 0;
int y = 0;
public Circle() {
setBackground(Color.BLACK);
Timer timer = new Timer(50, new ActionListener() {
public void actionPerformed(ActionEvent e) {
x += 5;
y += 5;
repaint();
}
});
timer.start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
}
}
I'm fairly new to java, so i don't think I have this fairly close to right, but I can seem to find any other help with this. Basically, I'm trying to animate a jPanel's background color so that it's hue (I'm using an hsb color model) changes. sort of like this: https://kahoot.it/#/ notice how the color kinda floats from one to another. Here is my code that I have so far:
public void animate(){
for(float i=.001f;i<1f;i+=.001f){
jPanel1.setBackground(Color.getHSBColor(i, .53f, .97f));
try{
Thread.sleep(5L);
}catch(InterruptedException ex){
}
System.out.println(i);
}
}
now i know this probably isn't right, but the loop works fine, the only problem is that the jPanel doesn't "update" until the loop is finished. Sorry all for being a huge noob at stuff like this, and thanks for any responses
The problem is that you are blocking the event dispatch thread, so no drawing can happen. Use a swing Timer instead of sleeping. A running example of changing HSB colors:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class ColorCycle {
private static class ColorPanel extends JPanel {
private final float stepSize;
private final Timer timer;
private int index;
ColorPanel(final int steps, int fps) {
stepSize = 1f / steps;
timer = new Timer(1000 / fps, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
index++;
if (index > steps) {
index = 0;
}
repaint();
}
});
}
void start() {
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.getHSBColor(index * stepSize, 1f, 1f));
g.fillRect(0, 0, getWidth(), getHeight());
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Colors");
ColorPanel panel = new ColorPanel(300, 20);
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
frame.pack();
frame.setVisible(true);
panel.start();
}
});
}
}
Works for me...
import java.awt.Color;
import java.lang.reflect.InvocationTargetException;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
public class HsbBackground {
public static void main(String[] args) throws Exception {
new HsbBackground();
}
private JPanel jPanel1 = new JPanel();
public HsbBackground() throws InvocationTargetException, InterruptedException {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
JFrame jFrame = new JFrame();
jFrame.setContentPane(jPanel1);
jFrame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
jFrame.setSize(400, 300);
jFrame.setVisible(true);
}
});
animate();
}
public void animate() {
for (float i = .001f; i < 1f; i += .001f) {
final float j = i;
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
jPanel1.setBackground(Color.getHSBColor(j, .53f, .97f));
}
});
try {
Thread.sleep(5L);
} catch (InterruptedException ex) {
}
System.out.println(i);
}
}
}
Make sure, that you call setVisible of your frame before you start your loop.
PS: I updated the code, so that GUI changes are all made from the event dispatching thread. The code still works fine.