I want to put my background image at the very bottom in this frame, and the button on top. However the code I wrote below doesn't work. Can anyone see where the problems are?
Another thing is that even though I set the location for my button, it keep showing at the top center on the frame.
Please ignore the comment lines. (I was just guessing, and hoping them will work, but they don't apparently.)
public class Menu extends JFrame{
private JLayeredPane pane;
private JLayeredPane pane2;
public Menu(){
final JFrame f = new JFrame("Chinese Chess");
JButton play = new JButton("Play vs. AI");
f.setLayout(new FlowLayout());
f.setLocationRelativeTo(null);
f.setSize(800, 800);
f.setVisible(true);
f.setResizable(false);
//f.pack();
pane = new JLayeredPane();
pane2 = new JLayeredPane();
f.add(pane);
f.add(pane2);
//background image
JLabel background = new JLabel(new ImageIcon("res/img/background.png"));
background.setLocation(0, 0);
background.setSize(800, 800);
pane.add(background, JLayeredPane.FRAME_CONTENT_LAYER);
pane2.add(play, JLayeredPane.DEFAULT_LAYER);
//pane.moveToBack();
//button PlayAI
play.setLocation(500,500);
play.setPreferredSize(new Dimension(100,50));
//f.setLayout(new FlowLayout());
//frame menu
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//f.getContentPane().add(play);
play.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
new PlayAI();
}
});
}
public static void main(String[] args){
new Menu();
}
Problems/Solutions:
setLocation(...) and setBounds(...) types of calls are ignored by most layout managers. The only way to use them is to set the layout of the container to null via .setLayout(null);
But having said that, while null layouts and setBounds() might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
So in sum -- don't do this, don't use null layouts or setBounds, but rather nest JPanels, each using its own layout manager, and thereby create easy to maintain and decent GUI's.
If you want an image to be in the background, then draw it in a JPanel that you use as a container for your GUI components by drawing it in the JPanel's paintComponent(Graphics g) method as has been demonstrated in many many similar questions on this site -- I'll find you some of mine in a second.
If you add any JPanels on top of this image drawing JPanel, be sure that you can see through them by calling setOpaque(false) on these overlying JPanels. Otherwise you'll cover up the image.
Your code has two JFrames when only one is needed. Get rid of the one you don't use.
You call setVisible(true) too early on the JFrame, before components have been added to the GUI -- don't. Call it only after adding everything to the GUI so all display OK.
You're creating two JLayedPanes, and completely covering one by the other by adding them to the JFrame without understanding how the JFrame's BorderLayout handles added components.
I suggest that you not even use one JLayeredPane but instead draw in the JPanel as noted above, and use that as your container.
Your code looks to be opening a completely new GUI window when the play button is pressed, and if so, this can get annoying to the user fast. Consider swapping views instead with a CardLayout.
For example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
// extend JPanel so you can draw to its background
#SuppressWarnings("serial")
public class Menu2 extends JPanel {
private BufferedImage bgImage = null; // our background image
private JButton playButton = new JButton(new PlayVsAiAction("Play Vs. AI", KeyEvent.VK_P));
public Menu2(BufferedImage bgImage) {
this.bgImage = bgImage;
setLayout(new GridBagLayout()); // center our button
add(playButton);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (bgImage != null) {
g.drawImage(bgImage, 0, 0, this);
}
}
// to size our GUI to match a constant or the image.
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
// if you want to size it based on the image
if (bgImage != null) {
int width = bgImage.getWidth();
int height = bgImage.getHeight();
return new Dimension(width, height);
} else {
return super.getPreferredSize();
}
// if you want to size the GUI with constants:
// return new Dimension(PREF_W, PREF_H);
}
private class PlayVsAiAction extends AbstractAction {
public PlayVsAiAction(String name, int mnemonic) {
super(name); // have our button display this name
putValue(MNEMONIC_KEY, mnemonic); // alt-key to press button
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO code to start program
}
}
private static void createAndShowGui() {
BufferedImage img = null;
String imagePath = "res/img/background.png";
try {
// TODO: fix this -- use class resources to get image, not File
img = ImageIO.read(new File(imagePath));
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
Menu2 mainPanel = new Menu2(img);
JFrame frame = new JFrame("Chinese Chess");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
Apart from the solution above... you should create and launch your swing application this way:
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
// Instantiate your JFrame and show it
}
Related
I have been struggling with this for some time. At first, I only used ActionListener, then I added the paintComponent, but I have no idea what to put there. I read some tutorials and used their code as an example, but it still doesn't work. Right now, the end result is the same as it was without PaintComponent.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Scream extends JPanel {
private JButton button = new JButton("OK");
private Color screenColor;
private JPanel panel = new JPanel();
private JFrame frame;
private Dimension screenSize;
private ImageIcon image;
private JLabel label = new JLabel(image);
private int x;
private int y;
private boolean mouseClicked;
public Scream() {
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e ) {
if (e.getSource() == button) {
mouseClicked = true;
frame.getContentPane().add(label);
frame.setSize(image.getIconWidth(), image.getIconHeight());
panel.repaint();
}
}
});
frame = new JFrame ("Existential angst");
screenColor = new Color(150, 100, 0);
panel.setBackground( screenColor );
frame.add(button, BorderLayout.PAGE_END);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1300, 700);
frame.setVisible(true);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
image.paintComponent(this, g, 1300, 700);
}
public static void main (String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Scream scream = new Scream();
}
});
}
}
If you are trying to dynamically add an image to a panel then you need to add the label to the panel. There is no need for any custom painting.
The basic code for adding components to a visible GUI is:
panel.add(...);
panel.revalidate();
panel.repaint();
Also, don't attempt to set the size of the frame to the size of the image. A frame contains a titlebar and borders. Instead you can use frame.pack();
I noticed a couple of issues:
image is never initialized to anything so it is null, effectively making the label empty. I assume maybe your example was just incomplete?
Once I initialized the image to something, your example still did not work. Turns out adding label without specifying any constraint basically does nothing (I assume since adding a component to a border layout without a constraint puts it in the center where panel already is). When I added the label to BorderLayout.NORTH, everything worked (though resizing the frame to the size of the image makes it only partially visible since the frame includes the OK button)
Background: Making a game in Swing. It is simple turn base game. Not a whole lot going on. Because of this I didn't think I would need to implement a Game Tick. Rather, my thought was when a component got changed or needed to be updated just simply revalidate/repaint that component on the fly rather than repainting the whole screen.
I have a GameJPanel which currently has all the components on it. This JPanel is the one that contains the components that get revalidated/repainted etc.
I figured I could make JLayeredPane that holds GameJPanel and my OptionJPanel. Have a Button on GameJPanel that when pressed causes the OptionJPanel to show on top of it and having its JPanel 50% transparent (so it gives the affect it dims the GameJPanel).
However, once I did this what happened was that the GameJPanel started to replace OptionJPanel components (because of the events... etc; repainting of the components).
So currently I am at a loss on what to do. I'm thinking if I had some sort of game tick I wouldn't be having this issue, however, I am not 100% certain. I'm a little worried if I implemented a gametick that the events in game will cause the GameJPanel components to show through for half a second then get replaced. There are some events that cause components to repaint themselves without manually doing it (like quick example for JLabel setText();)
As an example of what I'm trying to go for.
I have tried with a CardLayout but I couldn't figure out how to have the OptionJPanel be on top of GameJPanel while seeing GameJPanel in the background (I tried setting background color, setOpaque(false)..., tried to limit Option JPanel size but I think the CardLayout stretches it (not 100% sure)) all I got was a gray background when doing so.
I would prefer not to go the CardLayout route because in the future I also plan on placing components on top of the GameJPanel (like someone clicks a button, have another panel on a different layer have a component slide in or out etc).
I use CardLayout a ton with my other components in GameJPanel to swap screens around, but haven't had the need to have the other components behind the one showing to show through.
Any ideas on how to go about this would be great or even example code that shows this.
As noted above, you would use a JDialog, a component that is easy to make (similar to making a JFrame) and easy to place. Simply place it "relative-to" the JFrame, e.g.,
myDialog.setLocationRelativeTo(myJFrame);
... and it will automatically center itself on the JFrame. The tricky part is dimming the underlying JFrame, and for this you would need to use a JGlassPane added to the JFrame's rootpane, one set with a background color that uses an alpha composite value. The tricky part with this is to draw the darker background without causing side effects, and to do this, please read Rob Camick's (StackOverflow user camickr) excellent tutorial on drawing in Swing with alpha composites which you can find here: Java Tips Weblog: Backgrounds with Transparency
An example of such a program is shown here:
import java.awt.Color;
import java.awt.Component;
import java.awt.Dialog.ModalityType;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class DialogEg {
// path to example image used as "game" background
private static final String IMG_PATH = "https://upload.wikimedia.org/"
+ "wikipedia/commons/7/76/Jump_%27n_Bump.png";
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
private static void createAndShowGui() {
// get the "game" background image, or exit if fail
BufferedImage img = null;
try {
URL imgUrl = new URL(IMG_PATH);
img = ImageIO.read(imgUrl);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
// pass "game" image into main JPanel so that it will be drawn
DeMainPanel mainPanel = new DeMainPanel(img);
JFrame frame = new JFrame("Dialog Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel); // add main JPanel to JFrame
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}
// main JPanel
#SuppressWarnings("serial")
class DeMainPanel extends JPanel {
private BufferedImage img; // background image
// JButton action that shows the JDialog and darkens the glasspane
private PauseAction pauseAction = new PauseAction("Pause");
public DeMainPanel(BufferedImage img) {
super();
this.img = img;
add(new JButton(pauseAction));
}
// draw the "game" background image within the JPanel if not null
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
// size this JPanel to match the image's size
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet() || img == null) {
return super.getPreferredSize();
}
int width = img.getWidth();
int height = img.getHeight();
return new Dimension(width, height);
}
}
// Action / ActionListener for JButton -- shows JDialog and darkens glasspane
#SuppressWarnings("serial")
class PauseAction extends AbstractAction {
private static final int ALPHA = 175; // how much see-thru. 0 to 255
private static final Color GP_BG = new Color(0, 0, 0, ALPHA);
private DeDialogPanel deDialogPanel = new DeDialogPanel(); // jpanel shown in JDialog
public PauseAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent e) {
// comp is our JButton
Component comp = (Component) e.getSource();
if (comp == null) {
return;
}
// create our glass pane
JPanel glassPane = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
// magic to make it dark without side-effects
g.setColor(getBackground());
g.fillRect(0, 0, getWidth(), getHeight());
super.paintComponent(g);
}
};
// more magic below
glassPane.setOpaque(false);
glassPane.setBackground(GP_BG);
// get the rootpane container, here the JFrame, that holds the JButton
RootPaneContainer win = (RootPaneContainer) SwingUtilities.getWindowAncestor(comp);
win.setGlassPane(glassPane); // set the glass pane
glassPane.setVisible(true); // and show the glass pane
// create a *modal* JDialog
JDialog dialog = new JDialog((Window)win, "", ModalityType.APPLICATION_MODAL);
dialog.getContentPane().add(deDialogPanel); // add its JPanel to it
dialog.setUndecorated(true); // give it no borders (if desired)
dialog.pack(); // size it
dialog.setLocationRelativeTo((Window) win); // ** Center it over the JFrame **
dialog.setVisible(true); // display it, pausing the GUI below it
// at this point the dialog is no longer visible, so get rid of glass pane
glassPane.setVisible(false);
}
}
// JPanel shown in the modal JDialog above
#SuppressWarnings("serial")
class DeDialogPanel extends JPanel {
private static final Color BG = new Color(123, 63, 0);
public DeDialogPanel() {
JLabel pausedLabel = new JLabel("PAUSED");
pausedLabel.setForeground(Color.ORANGE);
JPanel pausedPanel = new JPanel();
pausedPanel.setOpaque(false);
pausedPanel.add(pausedLabel);
setBackground(BG);
int eb = 15;
setBorder(BorderFactory.createEmptyBorder(eb, eb, eb, eb));
setLayout(new GridLayout(0, 1, 10, 10));
add(pausedPanel);
add(new JButton(new FooAction("RESUME")));
add(new JButton(new FooAction("RESTART")));
add(new JButton(new FooAction("EXIT TO MAP")));
}
// simple action -- all it does is to make the dialog no longer visible
private class FooAction extends AbstractAction {
public FooAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent e) {
Component comp = (Component) e.getSource();
Window win = SwingUtilities.getWindowAncestor(comp);
win.dispose(); // here -- dispose of the JDialog
}
}
}
The GUI looks like this initially:
but then when the dialog shows and the glass pane is darkened, it looks like this:
So after about a month of working on my game I was drawn to this post once again. I implemented part of my game with what DontKnowMuchButGettingBetter's way and also implemented this by just adding the components to the GlassPane so to speak (Made a JPanel, set it to be GlassPane, did whatever on that Panel)...
The later implementation (GlassPane), isn't the best way to go about this because then you can't use the glass pane for other useful things.
I came back to my original idea to use a JLayeredPane. Having different Components on different levels and working off that. My issue before was that when components were getting repainted, the components in the backer layers were over painting the ones in the front layer.
Well I just came across a method called isOptimizedDrawingEnabled()... By making this method always return false for the JLayeredPane I was able to achieve what I wanted.
I am new to Java....I studied that we can add two things on frame... I added button and in response by clicking on button I want rectangle as output....but i don't understand that..Why i am not getting output.....
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class customizedgui5 implements ActionListener {
JButton button;
JFrame frame;
public static void main(String[] args) {
customizedgui5 hi = new customizedgui5();
hi.go();
}
public void go() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("click me");
button.addActionListener(this);
myclass a = new myclass();
frame.getContentPane().add(button, BorderLayout.CENTER);
frame.getContentPane().add(a, BorderLayout.SOUTH);
frame.setSize(100, 100);
frame.setVisible(true);
}
public void actionPerformed(ActionEvent event) {
frame.repaint();
frame.revalidate();
}
}
class myclass extends JPanel {
public void paintComponent(Graphics g) {
g.setColor(Color.orange);
g.fillRect(20, 50, 100, 100);
}
}
I would start by taking a look at Performing Custom Painting.
The main problem in your code is you are getting NullPointerException when you click the button because the reference of frame is null.
It is null because you've shadowed it in the constructor (basically, declared another variable of the same name within the constructor)...
// I'm null..
JFrame frame;
public void go() {
// Not the same as frame above...
JFrame frame = new JFrame();
You are also going to not see any changes because of a number of reasons...
The myclass panel has no size. With BorderLayout, this won't be "too" much of a problem, but...
You've drawing outside of the visible range of the panel. The rectangle you are painting won't appear because it is being painted outside of the width and height of the panel.
The rectangle will appear before you press the button as paintComponent will be called to update the state of the panel once it's made visible on the screen...
The first thing you need to is provide some kind of size hints to the BorderLayout. Try adding...
#Override
public Dimension getPreferredSize() {
return new Dimension(120, 150);
}
To myclass.
You also don't need to repaint the frame, what you really want to repaint is the instance of myclass. Try updating customizedgui5 so that a becomes a instance variable (like frame...
//...
myclass a;
//...
public void go() {
//...
a = new myclass();
//...
}
public void actionPerformed(ActionEvent event) {
a.repaint();
}
Now, the rectangle will still be shown the moment that the panel is made visible on the screen. Sure you could try setting it invisible, but this will affect the layout of the frame, hiding your component to start with, so, instead, we need some kind of flag we can trip so we know when to paint the rectangle. This is easily achieved by using a simple boolean variable, for example...
class myclass extends JPanel {
private boolean paintRect;
public void setPaintRect(boolean paint) {
paintRect = paint;
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(120, 150);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (paintRect) {
g.setColor(Color.orange);
g.fillRect(20, 50, 100, 100);
}
}
}
Then in you actionPerformed method, you just need to set the flag...
public void actionPerformed(ActionEvent event) {
a.setPaintRect(true);
}
You may also want to take a read through Code Conventions for the Java Programming Language. It will make it easier for people to read your code...
When you click on your button, you're calling the method actionPerformed(ActionEvent event)
Take a look at what you did there. Currently, you repaint and re-validate the frame. If you want to add a rectangle to your frame, you need to do so by adding a new component to the frame that will draw the rectangle.
You could add another instance of your myclass JPanel which paints a rectangle like so:
public void actionPerformed(ActionEvent event) {
frame.getContentPane().add(new myclass(), BorderLayout.NORTH);
frame.repaint();
}
This would add your custom rectangle-drawing panel to the North section of your BorderLayout. If you want to add the rectangle "on top of" your button, you should embed your button within a JPanel, then add the rectangle-drawing panel to that instead of your main JFrame
I want to put a JPanel in a JApplet, the problem is that I can't see it :( I've overridden the paintComponent of my JPanel in order to have a background image, but I can't see anything. When I remove the paintComponenet method that I had overriden, and set a color to the background of this panel, it seems that JPanel fills the JApplet and still no component is visible :-S I've tried different layouts. I also put my panel in the center of another panel which fills my JApplet but nothing changed, and still no component and no background image is visible :(
import java.awt.BorderLayout;
import java.awt.Graphics;
import javax.swing.ImageIcon;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Main extends JApplet implements Runnable{
private JTextArea display;
private Thread outputThread;
JPanel boardPanel;
private ClientViewManager view;
#Override
public void init() {
try {
javax.swing.SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
createGUI();
}
});
} catch (Exception e) {
System.err.println("createGUI didn't successfully complete");
}
}
private void createGUI() {
display = new JTextArea(4, 30);
display.setEditable(false);
getContentPane().add(new JScrollPane(display), BorderLayout.SOUTH);
setFocusable(true);
setVisible(true);
setName("CE Tanks");
setSize(600, 600);
setLocation(100, 100);
boardPanel = new JPanel();
boardPanel.setLayout(null);
boardPanel.setBackground(new java.awt.Color(128, 255, 255));
getContentPane().add(boardPanel, BorderLayout.CENTER);
}
public void start() {
outputThread = new Thread(this);
outputThread.start();
}
public void run() {
view = new ClientViewManager();
boardPanel.add(view);
boardPanel.repaint();
repaint();
}
}
class ClientViewManager extends JPanel {
private int rows=8;
private int columns=8;
public ClientViewManager() {
super(null);
JLabel lb= new JLabel("lb.jpg");
lb.setLocation(10, 10);
lb.setSize(50, 50);
lb.setOpaque(false);
lb.setVisible(true);
this.add(lb);
}
public void paintComponent(Graphics g) {
g.drawImage(new ImageIcon("ground.jpg").getImage(), 0, 0, columns * 50,
rows * 50, this);
}
}
The code above can be compiled. I cant even add Keylistener to neither my JPanel nor to my JApplet. I used java.awt.KeyEventDispatcher and in dispatchKeyEvent(KeyEvent e) I printed something in console but, it was printed 3 times. :(
I've overridden the paintComponent of my JPanel inorder to have a background image,
But you didn't add the custom component to your applet:
//boardPanel = new JPanel();
boardPanel = new ClientViewManager();
Also:
get rid of setVisible(). This is not required for any of the controls in your program. By default all components except top level Container (Jframe, JDialog etc) are already visible. In the case of JApplet, you don't need to make it visible as this is part of the process of displaying an applet.
get rid of setSize() and setLocation() you can't control the position of the applet this way.
Don't read the image file in the paintComponent() method. This is not efficient as this method is invoked whenever Swing determines the component needs to be repainted.
JLabels are opaque by default so there is not need to invoke the setOpaque method.
When doing custom painting you should also override the getPreferredSize() method of the component to return the proper size of the custom painting so layout managers can use this information. It works in this case because you added the panel to the CENTER of the BorderLayout. Try adding the panel to the NORTH to see what happens.
Edit:
Now I see where you are adding the ClientViewManager. I'm not sure why you are trying to do this with a Thread but once again there are several problems.
When you add/remove components from a visble GUI then the basic code is:
panel.add(...);
panel.revalidate();
panel.repaint();
However this still won't work because you are using a null layout and the size of the panel is 0. Use a proper layout manager and implement the getPreferredSize() method as suggest above and the component will be displayed properly.
I recommend you to use the GUI Builder of Netbeans to build a GUI like that, and then compare the generated code to your code. Netbeans results really useful to help you create swing code.
I have 2 JPanels in a JTabbedPane and when update(g) is called on a panel inside the first panel (Its an animation) even if the second panel is the selected panel(i.e the one you can see) the updated panel appears on the screen. Why is this and how can i circumvent this behaviour?
The update() method of JComponent "doesn't clear the background," so you may need to do that explicitly. Typical examples of JTabbedPane don't usually require using update(). Perhaps an sscce showing your usage might help.
Addendum 1: It's not clear why you are calling update(). Below is a simple animation that does not exhibit the anomaly.
Addendum 2: See Painting in AWT and Swing: paint() vs. update(). You may want to use repaint() in actionPerformed() instead.
import java.awt.*;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class JTabbedTest {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
//#Override
public void run() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTabbedPane jtp = new JTabbedPane();
jtp.setPreferredSize(new Dimension(320, 200));
jtp.addTab("Reds", new ColorPanel(Color.RED));
jtp.addTab("Greens", new ColorPanel(Color.GREEN));
jtp.addTab("Blues", new ColorPanel(Color.BLUE));
f.add(jtp, BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
});
}
private static class ColorPanel extends JPanel implements ActionListener {
private final Random rnd = new Random();
private final Timer timer = new Timer(1000, this);
private Color color;
private int mask;
private JLabel label = new JLabel("Stackoverflow!");
public ColorPanel(Color color) {
super(true);
this.color = color;
this.mask = color.getRGB();
this.setBackground(color);
label.setForeground(color);
this.add(label);
timer.start();
}
//#Override
public void actionPerformed(ActionEvent e) {
color = new Color(rnd.nextInt() & mask);
this.setBackground(color);
}
}
}
when update(g) is called on a panel
inside the first panel (Its an
animation)
Overriding the update(...) method is an old AWT trick and should never be used with Swing.
Read the section from the Swing tutorial on Custom Painting for the proper way to do this. And for animation read up on "How to Use Swing Timer" found in the tutorial as well.