Trying ti change the BG image of a jpanel but i cant call poaint on any normal method, it works great when i'm building the constructor but i don't want to rebuild the constructor.
....
Sort of found a solution by putting a label in my center frame and calling setIcon but i need to be able to pull the relelevant info so i need to find a way to store a value into my Jtoggle button (the id of the Race or class so i can fetch it's picture and change the icon)
thoughts? Everything compiles outside the iff statement which is my sticking point
RaceButtons_lft[i] = new JToggleButton();
RaceButtons_lft[i].addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
JToggleButton cb = (JToggleButton)ae.getSource();
for (int j=0; j<MyRaceArray.size(); j++)
{
if (MyRaceArray.get(j).getraceID() == combo_contents.getIndex()){//here is my sticking point, i need to find a way to match MyRaceArray's getRaceID to some value saved withthe Toggle button
final ImageIcon BGCSMs = ScaledImageIcon("Fantasy_Landscape_01.jpg", "Profile Pic", (468-(60*2)), 285);
picLabel.setIcon(BGCSMs);
}//if
}//for
}//action performed;
});//button add action listener
Calling
super.paintComponent(..)
will probably - depending on the super class - fill the component with the background color.
public void paintComponent(Graphics g) {
// Let UI Delegate paint first, which
// includes background filling since
// this component is opaque.
super.paintComponent(g);
g.drawString("This is my custom Panel!",10,20);
redSquare.paintSquare(g);
}
(see A Closer Look at the Paint Mechanism). You don't need repaint(..) in this case.
You could be suffering from a number of problems, which we can't see because we don't have enough context...
You could have a reference issue, instead of trying to repaint the component on the screen, you've inadvertently gotten the wrong reference...
You could be shadowing your variables...
You could be painting to a opaque component...
Assuming that the code you have posted is linear (ie, it appears in you code in this exact order or close enough to it), I can see one possible problem...
ImageIcon RCicon = createImageIcon(temp_race.getActiveHeadshot(), temp_race.getRaceNameString(race.getraceID()));
Image RCimg = RCicon.getImage();
RCimg = RCimg.getScaledInstance((468-(60*2)), 285, java.awt.Image.SCALE_SMOOTH);
portraitCenterOptions.setBackground(Color.White){
protected void paintComponent(Graphics h)
{
//...//
// There is no way that this reference can be valid...
// The image created above will only have a local reference unto itself
// suggestion that you're shadowing your variables...
final ImageIcon bodypicSM = new ImageIcon(RCimg);
//...//
}
};
But without a working example, it's impossible to know...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.text.DateFormat;
import java.util.Date;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ChangeBackground {
public static void main(String[] args) {
new ChangeBackground();
}
public ChangeBackground() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
final PaintPane pane = new PaintPane();
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(pane);
JButton change = new JButton("Change");
change.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
pane.changeBackground();
pane.repaint();
}
});
frame.add(change, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class PaintPane extends JPanel {
private BufferedImage bg;
private int changes = 0;
public PaintPane() {
changeBackground();
}
public void changeBackground() {
bg = new BufferedImage(200, 200, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = bg.createGraphics();
FontMetrics fm = g.getFontMetrics();
g.setColor(getForeground());
String[] text = {
"I've been changed " + changes + " times",
"Last changed at " + DateFormat.getDateTimeInstance().format(new Date())};
int y = (200 - (fm.getHeight() * 2)) / 2;
for (String value : text) {
int x = (200 - fm.stringWidth(value)) / 2;
g.drawString(value, x, y + fm.getAscent());
y += fm.getHeight();
}
g.dispose();
changes++;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - bg.getWidth()) / 2;
int y = (getHeight() - bg.getHeight()) / 2;
g.drawImage(bg, x, y, this);
}
}
}
Call repaint() on the component after you have finished your changes to the background
so ultimately tried a few thing and just got lazy, added a label in the center and called "SetIcon, does what I need it to do, thanks for the ideas though.
Related
I started programming in SWING class recently and I try to set Image (like Space) and on it image(like spaceShip) like background. I
would love for you to help me,
Here is my code
public class SpaceWar {
static JFrame frame = new JFrame("Space War");
static JPanel panel = new JPanel();
public static void main(String[] args) {
new SpaceWar();
//frame.setResizable(false);
frame.setVisible(true);
}
public SpaceWar() {
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
Dimension size
= Toolkit.getDefaultToolkit().getScreenSize();
frame.setPreferredSize(size);
frame.setLayout(null);
panel.setLayout(null);
panel.setBounds(frame.getPreferredSize().width/4,0,
frame.getPreferredSize().width/2,frame.getPreferredSize().height);
frame.add(panel);
frame.add(new Background());
spaceShip sp1 = new spaceShip();
panel.setBackground(Color.black);
panel.add(sp1);
System.out.println(panel.getPreferredSize().width);
}
}
class spaceShip extends JLabel{
static ImageIcon img = new ImageIcon("spaceShip.png");
public spaceShip(){
sizeIcon(100,100,img);
setIcon(img);
}
public static ImageIcon sizeIcon(int w,int h,ImageIcon image1){
Image image = image1.getImage(); // transform it
Image newimg = image.getScaledInstance(w,h, java.awt.Image.SCALE_SMOOTH); // scale it the smooth way
ImageIcon img1 = new ImageIcon(newimg); // transform it back
return img1;
}
}
class Background extends JPanel{
public void paint(Graphics g) { // paint() method
super.paint(g);
ImageIcon image = new ImageIcon("space.jpg");
Image bg = image.getImage();
g.drawImage(bg,0,0,null);
}
}
So, your "core" problem is the use of null layouts and a lack of understand of how components are sized and positioned. Having said that, if your aim is to make a game, this probably isn't the best approach anyway.
Instead, I'd focus on creating a "surface", onto which you can paint all your assets directly, this will give you much greater control.
Start by taking a look at Painting in AWT and Swing and Performing Custom Painting to get a better understanding how the paint system works and how you can work with it to perform custom painting.
I'd also avoid ImageIcon, it's not the best way to handle images, instead, take a look at ImageIO (Reading/Loading an Image), it will generate an IOException if the image can't be loaded and will return a fully realised image (unlike ImageIcon which off loads the image loading to a background thread).
For example...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
public class MainPane extends JPanel {
private BufferedImage ufo;
private BufferedImage background;
private int horizontalPosition = 106;
public MainPane() throws IOException {
ufo = ImageIO.read(getClass().getResource("/images/ufo.png"));
background = ImageIO.read(getClass().getResource("/images/starfield.png"));
System.out.println("background = " + background);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
paintBackground(g2d);
paintUFO(g2d);
g2d.dispose();
}
protected void paintBackground(Graphics2D g2d) {
int x = (getWidth() - background.getWidth()) / 2;
int y = (getHeight() - background.getHeight()) / 2;
g2d.drawImage(background, x, y, this);
}
protected void paintUFO(Graphics2D g2d) {
int x = (getWidth() - ufo.getWidth()) / 2;
int y = (getHeight() - ufo.getHeight()) / 2;
g2d.drawImage(ufo, x, y, this);
}
}
}
The example makes use of embedded resources (something to read up on). Managing your assets this way will save you countless hours of wondering why they aren't loading/working. How you achieve this will come down to your IDE and build system, for example, Netbeans and Eclipse will allow you to add resources directly to the src directory, when you're not using maven.
At some point, you're going to want to learn about How to Use Swing Timers and How to Use Key Bindings
I am trying to make a simple java game, and i got stumped on this. The game requires that you play in a square window, but can resize the sprites on the canvas. I though it would be really annoying if I used a ComponentListener and didn't let the user change size, so I thought that I would just offset the canvas from the left and right side so that it is centered until it is square.
Right now I understand that I need to create a Canvas object for the Game, and then offset it but I'm not sure how.
Game Canvas:
public class GameCanvas extends Canvas {
public Vector size;
public GameCanvas(Vector size) {
this.size = size;
setBackground(Color.BLUE);
setSize(size.x, size.y);
}
}
Any help is appreciated :) thank you.
You could...
Make your own layout manager which maintained the Canvas in a square shape based on the available space of the parent Container.
This might be a little bit of over kill, but, it's generally more efficient and means you can keep using the properties of the Canvas (ie getWidth and getHeight), so it's more de-coupled from other solutions
You could...
Calculate a "playable area" based on the size of the Canvas and use that as the bounds range checking, for example...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JFrame;
import javax.swing.JPanel;
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 {
public TestPane() {
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected Rectangle getPlayableBounds() {
Dimension size = getSize();
int playableSize = Math.min(size.width, size.height);
int x = (size.width - playableSize) / 2;
int y = (size.height - playableSize) / 2;
return new Rectangle(x, y, playableSize, playableSize);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.BLACK);
g2d.draw(getPlayableBounds());
g2d.dispose();
}
}
}
This example is not optimised, as calling getPlayableBounds recalculates the playable area, regardless if its changed since the last call or not.
I'd be tempted to use a ComponentListener and make the playableBounds an instance field. When the component is resized, I'd simply invalidate the playableBounds property, which would force the getPlayableBounds to recalculate the value and cache the result
I'd like to make a Java panel that creates objects where the user clicks. Since my actual application uses a MVC approach I'd like also for these objects to be able to repaint themselves when a model is changed, and provide menus to change their properties.
I think that the best way to control their x and y locations would be to take a canvas based approach whereby the JPanel calls a draw method on these objects from the paintComponent method. This however will only draw the shape on the canvas and does not add the object itself loosing all abilities to control object properties. I'd be very grateful if someone could tell me the best approach for what I want to do.
I've created some sample code which can be seen below. When clicked I'd like the circle to change colour, which is implemented using a MouseListener (it basically represents changing the models properties in this small example). Also I'd just like to make sure that zooming in/out still works with any sample code/advice can provide so I've added buttons to zoom the objects in and out as a quick test.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import java.awt.geom.Ellipse2D;
public class Main {
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ExamplePanel panel = new ExamplePanel();
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
});
}
//I could not get this to with when it extended JLayeredPane
private static class ExamplePanel extends JPanel {
private static final int maxX = 500;
private static final int maxY = 500;
private static double zoom = 1;
private static final Circle circle = new Circle(100, 100);
public ExamplePanel() {
this.setPreferredSize(new Dimension(maxX, maxY));
this.setFocusable(true);
Button zoomIn = new Button("Zoom In");
zoomIn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
zoom += 0.1;
repaint();
}
});
add(zoomIn);
Button zoomOut = new Button("Zoom Out");
zoomOut.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
zoom -= 0.1;
repaint();
}
});
add(zoomOut);
// add(circle); // Comment back in if using JLayeredPane
}
#Override
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.scale(zoom, zoom);
super.paintComponent(g);
circle.paint(g); // Comment out if using JLayeredPane
}
}
static class Circle extends JPanel {
private Color color = Color.RED;
private final int x;
private final int y;
private static final int DIMENSION = 100;
public Circle(int x, int y) {
// setBounds(x, y, DIMENSION, DIMENSION);
this.x = x;
this.y = y;
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
color = Color.BLUE;
}
#Override
public void mouseReleased(MouseEvent e) {
}
});
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(color);
g2.fillOval(x, y, DIMENSION, DIMENSION);
}
// I had some trouble getting this to work with JLayeredPane even when setting the bounds
// In the constructor
// #Override
// public void paintComponent(Graphics g) {
// Graphics2D g2 = (Graphics2D) g;
// g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// g2.setPaint(color);
// g2.fillOval(x, y, DIMENSION, DIMENSION);
// }
#Override
public Dimension getPreferredSize(){
return new Dimension(DIMENSION, DIMENSION);
}
}
}
As an aside I did try using a JLayeredPane(useful because I'd also like to layer my objects) but could not get my objects to even render. I know it has no default layout manager so tried calling setBounds in the circle in the constructor, but sadly it did not work. I know it's better to use a layout manager but can't seem to find one suitable for my needs!
Thanks in advance.
Don't override paint components, use paintComponent and don't forget to call super.paintComponent
A component already has a concept of "location", so when painting, the top left position of your component is actually 0x0
What you are doing is actually painting beyond the boundaries of you component
For example, if you place your Circle at 100x100 and then did...
g2.fillOval(x, y, DIMENSION, DIMENSION);
You would actually start painting at 200x200 (100 for the actual location of the component and 100 for you additional positioning).
Instead use
g2.fillOval(x, y, DIMENSION, DIMENSION);
And go back and try using JLayeredPane.
You could actually write your own layout manager that takes the location of the component and it's preferred size and updates the components bounds and then apply this to a JLayeredPane. This gives you the "benefits" of an absolute layout, but keeps you within how Swing works to update its components when things change.
You should also be careful with doing anything like...
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
The Graphics context is a shared resource. That means, anything you apply to, will still be in effect when the next component is painted. This may produce some strange results.
Instead try using...
Graphics2D g2 = (Graphics2D) g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//...
g2.dispose();
Updated
For zooming I would take a closer look at JXLayer (or JLayer in Java 7)
The JXLayer (and excellent PBar extensions) have gone quite on the net, so you can grab a copy from here
(I tried finding a better example, but this is the best I could do with the limited time I have available)
Updated with working zooming example
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.RenderingHints;
import java.util.HashMap;
import java.util.Map;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import org.jdesktop.jxlayer.JXLayer;
import org.pbjar.jxlayer.demo.TransformUtils;
import org.pbjar.jxlayer.plaf.ext.transform.DefaultTransformModel;
public class TestJLayerZoom {
public static void main(String[] args) {
new TestJLayerZoom();
}
public TestJLayerZoom() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JXLayer<JComponent> layer;
private DefaultTransformModel transformModel;
private JPanel content;
public TestPane() {
content = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridy = 0;
JLabel label = new JLabel("Hello");
JTextField field = new JTextField("World", 20);
content.add(label, gbc);
content.add(field, gbc);
gbc.gridy++;
gbc.gridwidth = GridBagConstraints.REMAINDER;
final JSlider slider = new JSlider(50, 200);
slider.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
int value = slider.getValue();
double scale = value / 100d;
transformModel.setScale(scale);
}
});
content.add(slider, gbc);
transformModel = new DefaultTransformModel();
transformModel.setScaleToPreferredSize(true);
Map<RenderingHints.Key, Object> hints = new HashMap<>();
//hints.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//hints.put(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
//hints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
layer = TransformUtils.createTransformJXLayer(content, transformModel, hints);
setLayout(new BorderLayout());
add(layer);
}
}
}
I've left the rendering hints in to demonstrate their use, but I found that they screwed with the positing of the cursor within the text field, but you might like to have a play
I'd just like to add that I fixed the zooming issue not in the way suggested by the answer, but just by keeping the line that applied a scaled transform call in the ExamplePanel paintComponent method:
g2.scale(zoom, zoom);
I thought that this was the nicest implementation since none of the components require any knowledge about zooming and it seemed far simpler than JLayer since I only required basic zooming functionalities.
I have created a KeyAdapter class within my JPanel class, and I tried debugging the click using System.out.println(String par1);
However it doesnt seem to work...
Here is the class:
package net.ryanshah;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
public class Menu extends JPanel
{
private GameFrame gf;
private Image bg = new ImageIcon("res/bg.png").getImage();
public Menu(final GameFrame parent) {
this.gf = parent;
int width = parent.getWidth();
int height = parent.getHeight();
setFocusable(true);
addKeyListener(new MenuOperator());
setBackground(Color.black);
setLayout(null);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
int w = getWidth();
int h = getHeight();
g2d.drawImage(bg, 0, 0, null);
}
public class MenuOperator extends KeyAdapter {
#Override
public void keyPressed(KeyEvent event) {
int keyCode = event.getKeyCode();
if(keyCode == KeyEvent.VK_SPACE) {
System.out.println("LOL");
}
}
}
}
Does anyone know what the problem might be? I have set the key handler in the frame as well as setting the frame to be focusable..
Thanks in advance
~RyanS.
Things not considered right in the code (IMHO) :
The way you accessing the images in your code. Consider ImageIO, over using the constructor of ImageIcon, as the former will notify you, in case something goes wrong. For more info, please refer, Loading Image Icon Exception, for more insight.
KeyListeners are for AWT, Swing on the other hand uses KeyBindings.
Before, setting background on any JComponent prefer to first set the opaque property of the said JComponent to true. Since, opaque property is usually dependent on LookAndFeel used.
Avoid the use of setLayout(null), as much as possible. Please walk through the first paragraph of Absolute Positioning for more information :-)
THe use of ImageObserver as already mentioned in the comments.
This blog Motion Using the Keyboard by #camickr, will again add loads to your knowledge, as to why KeyListeners are not considered a better option and why KeyBindings is more suited for such needs :-)
Please have a look at this example :
import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class TestMenu extends JPanel {
private Image bg;
public TestMenu() {
try {
bg = ImageIO.read(
new URL("http://i.imgur.com/Aoluk8n.gif"));
} catch (Exception e) {
e.printStackTrace();
}
getInputMap().put(KeyStroke.getKeyStroke("SPACE"), "SPACE key");
getActionMap().put("SPACE key", keyAction);
setOpaque(true);
setBackground(Color.black);
}
private Action keyAction = new AbstractAction() {
#Override
public void actionPerformed(ActionEvent ae) {
System.out.println("LOL");
}
};
/*
* Make this a customary habbit to override
* this method for the JPanel/JComponent,
* when ever you extend any of the above classes
*/
#Override
public Dimension getPreferredSize() {
return (new Dimension(200, 200));
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int w = getWidth();
int h = getHeight();
/*
* Here the last part of the drawImage is the
* ImageObserver, here it is a good practise
* to keep the instance of the JPanel on which
* we drawing the image to be notified, till the
* end, till the image loading is not complete
*/
g2d.drawImage(bg, 0, 0, this);
}
private void displayGUI() {
JFrame frame = new JFrame("Painting Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setContentPane(this);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
Runnable runnable = new Runnable() {
#Override
public void run() {
new TestMenu().displayGUI();
}
};
EventQueue.invokeLater(runnable);
}
}
Setting your panel focusable is not enough - panel cannot get focus on its own - you have to request the focus on some kind of event. For example you can add a mouse listener to your panel and call panel.requestFocusInWindow() when you click on it.
Key listener will work only if component on which you add it has focus.
So I am creating a basic application that I want to have a JLabel at the bottom of the screen that starts at the left bottom corner and moves, animation style, to the right bottom corner in a set time, and a static image in the center. To do this, I created a JFrame with a JPanel using BorderLayout. There is a JLabel with an ImageIcon added to BorderLayout.CENTER and a JPanel at BorderLayout.SOUTH. My code, while hastily written and far from pretty, is:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.BorderFactory;
public class GameWindow extends JPanel{
private static JLabel mainWindow, arrowLabel, arrowBox;
protected static JFrame frame;
protected static JPanel arrows;
public static int x = 600;
public GameWindow(){
mainWindow = new JLabel("Center");
arrowLabel = new JLabel("Moving");
arrows = new JPanel();
arrows.setSize(600, 100);
arrows.setLayout(null);
arrowBox = new JLabel("");
arrowBox.setBounds(0, 0, 150, 100);
arrowBox.setPreferredSize(new Dimension(150, 100));
arrowBox.setBorder(BorderFactory.createLineBorder(Color.black));
arrows.add(arrowBox);
this.setSize(600,600);
this.setLayout(new BorderLayout());
this.add(mainWindow, BorderLayout.CENTER);
this.add(arrows, BorderLayout.SOUTH);
}
public static void main(String[] args)
{
GameWindow g = new GameWindow();
frame = new JFrame("Sword Sword Revolution");
frame.add(g);
frame.setSize(600,600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
Timer t = new Timer(1000, new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
arrows.add(arrowLabel);
arrowLabel.setBounds(x, 100, 100, 100);
x-=50;
arrows.repaint();
frame.repaint();
}
});
t.start();
}
}
The ImageIcon in the center JLabel appears fine, and the empty JLabel with a border appears at the bottom, but I cannot get the second JLabel with the arrow image to show up on screen. Eventually I will change to scheduleAtFixedRate to continuously move the JLabel, but right now I can't even get the image to appear on screen.
I also understand that I will most likely not be able to use FlowLayout for this, as I understand it does not allow you to set the location of your components. I tried using null layout, but with null layout the empty JLabel with a border does not appear. I can barely make out the top of the border at the bottom edge of the frame, but even with setLocation I cannot get it to appear where I want it to.
Obviously, my thought process is flawed, so any help would be appreciated.
Your use of threading is all wrong for Swing applications. You should not be trying to add or remove components in a background thread but instead should use a Swing Timer to do this on the Swing event thread.
Also, what do you mean by:
I want to have a scrolling JLabel at the bottom of the screen
Please clarify the effect you're trying to achieve.
Also regarding,
I also understand that I will most likely not be able to use FlowLayout for this, as I understand it does not allow you to set the location of your components. I tried using null layout, but with null layout the empty JLabel with a border does not appear. I can barely make out the top of the border at the bottom edge of the frame, but even with setLocation I cannot get it to appear where I want it to.
No, don't use null layout for this situation. There are much better layout managers that can help you build your application in a cleaner more platform-independent manner.
Edit 3
Regarding:
To clarify, at the bottom of the screen I want a JLabel at the far right corner, then in the swing timer, the JLabel will gradually move to the left until it leaves the screen. If I could get setLocation to work, the basic premise would be to have a variable x set to 600, and then every second decrement x by say 50 and then redraw the JLabel at the new location on the screen. Basic animation.
I would create a JPanel for the bottom of the screen for the purposes of either holding your JLabel or displaying the image without a JLabel by overriding its paintComponent(...) method. If you use it as a container, then yes, its layout should be null, but the rest of the GUI should not be using null layout. The Swing Timer would simply change the JLabel's location and then call repaint() on its JPanel/container. If you go the latter route, you would draw the image in the JPanel's paintComponent(...) method using g.drawImage(myImage, x, y), and your timer would change x and/or y and call repaint() on the drawing JPanel.
Also, you likely do not want to keep adding a JLabel in your timer but rather simply moving the JLabel that's already displayed in the GUI.
Also, to avoid focus issues, don't use a KeyListener to capture keystroke input but rather use Key Bindings. Google will direct you to a great tutorial on this construct.
Edit 4
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.EnumMap;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class AnimateExample extends JPanel {
public static final String DUKE_IMG_PATH =
"https://duke.kenai.com/iconSized/duke.gif";
private static final int PREF_W = 800;
private static final int PREF_H = 800;
private static final int TIMER_DELAY = 20;
private static final String KEY_DOWN = "key down";
private static final String KEY_RELEASE = "key release";
public static final int TRANSLATE_SCALE = 3;
private static final String BACKGROUND_STRING = "Use Arrow Keys to Move Image";
private static final Font BG_STRING_FONT = new Font(Font.SANS_SERIF,
Font.BOLD, 32);
private EnumMap<Direction, Boolean> dirMap =
new EnumMap<AnimateExample.Direction, Boolean>(Direction.class);
private BufferedImage image = null;
private int imgX = 0;
private int imgY = 0;
private int bgStringX;
private int bgStringY;
public AnimateExample() {
for (Direction dir : Direction.values()) {
dirMap.put(dir, Boolean.FALSE);
}
try {
URL imgUrl = new URL(DUKE_IMG_PATH);
image = ImageIO.read(imgUrl);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
new Timer(TIMER_DELAY, new TimerListener()).start();
// here we set up our key bindings
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
ActionMap actionMap = getActionMap();
for (final Direction dir : Direction.values()) {
// for the key down key stroke
KeyStroke keyStroke = KeyStroke.getKeyStroke(dir.getKeyCode(), 0,
false);
inputMap.put(keyStroke, dir.name() + KEY_DOWN);
actionMap.put(dir.name() + KEY_DOWN, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
dirMap.put(dir, true);
}
});
// for the key release key stroke
keyStroke = KeyStroke.getKeyStroke(dir.getKeyCode(), 0, true);
inputMap.put(keyStroke, dir.name() + KEY_RELEASE);
actionMap.put(dir.name() + KEY_RELEASE, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
dirMap.put(dir, false);
}
});
}
FontMetrics fontMetrics = getFontMetrics(BG_STRING_FONT);
int w = fontMetrics.stringWidth(BACKGROUND_STRING);
int h = fontMetrics.getHeight();
bgStringX = (PREF_W - w) / 2;
bgStringY = (PREF_H - h) / 2;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g.setFont(BG_STRING_FONT);
g.setColor(Color.LIGHT_GRAY);
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.drawString(BACKGROUND_STRING, bgStringX, bgStringY);
if (image != null) {
g.drawImage(image, imgX, imgY, this);
}
}
private class TimerListener implements ActionListener {
public void actionPerformed(java.awt.event.ActionEvent e) {
for (Direction dir : Direction.values()) {
if (dirMap.get(dir)) {
imgX += dir.getX() * TRANSLATE_SCALE;
imgY += dir.getY() * TRANSLATE_SCALE;
}
}
repaint();
};
}
enum Direction {
Up(KeyEvent.VK_UP, 0, -1), Down(KeyEvent.VK_DOWN, 0, 1), Left(
KeyEvent.VK_LEFT, -1, 0), Right(KeyEvent.VK_RIGHT, 1, 0);
private int keyCode;
private int x;
private int y;
private Direction(int keyCode, int x, int y) {
this.keyCode = keyCode;
this.x = x;
this.y = y;
}
public int getKeyCode() {
return keyCode;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
private static void createAndShowGui() {
AnimateExample mainPanel = new AnimateExample();
JFrame frame = new JFrame("Animate Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Which will create this GUI:
Three possibilities:
You can either use a library like SlidingLayout to create such transition with very few lines of code. You won't be able to tweak the animation but your life will be easier.
You can use an animation engine like the Universal Tween Engine to configure everything by hand and tweak the animation as much as you want (the first lib uses this one under the hood). Using such engine, you can animate what you want: positions, colors, font size, ...
You can code everything by hand and embrace the hell that is the animation world :)
In the end, you'll be able to quickly create animations like these (it's a tool I'm currently working on, used to configure eclipse projects for android dev using the LibGDX game framework):
I made these libraries to ease the pain that is UI animation (I love UI design :p). I released them open-source (free to use, license apache-2), hoping they may help some people too.
If you need help, there is a dedicated help forum for each library.
Very simple, look at this:
javax.swing.JLabel lb = new javax.swing.JLabel();
Image image = Toolkit.getDefaultToolkit().createImage("Your animated GIF");
ImageIcon xIcon = new ImageIcon(image);
xIcon.setImageObserver(this);
lb.setIcon(xIcon);