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When button clicked, replace entire window content with an image

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So I have an issue where when I click the button, I want an image to replace the entire content of the window. But it's only replacing, what I believe to be, a part of a panel. Should I not use panels in this instance? I found some code online which didn't use panels which worked, but maybe there is a scenario where I can remove the panel and just cover the entire frame with my image when the button is clicked?
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class SatNav extends JFrame {
private JFrame frame;
private JPanel panel;
private JLabel satelliteLabel;
private JLabel aboutLabel;
private JButton satellite;
private JButton about;
public SatNav() {
frame = new JFrame("Work Package 5");
frame.setVisible(true);
frame.setSize(300, 380);
about = new JButton("About");
add(about);
event abo = new event();
about.addActionListener(abo);
panel = new JPanel();
frame.add(panel);
panel.add(about);
setLocationRelativeTo(null); //This is for centering the frame to your screen.
setDefaultCloseOperation(EXIT_ON_CLOSE); //This for closing your application after you closing the window.
}
public class event implements ActionListener {
public void actionPerformed(ActionEvent abo) {
ImagePanel imagePanel = new ImagePanel();
//JFrames methods
panel.add(imagePanel, BorderLayout.CENTER);
revalidate();
repaint();
about.setVisible(false);
//satellite.setVisible(false);
}
}
public class ImagePanel extends JPanel {
private BufferedImage image;
public ImagePanel() {
try {
image = ImageIO.read(new File("about.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
setBorder(BorderFactory.createLineBorder(Color.black, 2));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, getWidth(), getHeight(), null);
}
}
public static void main(String[] args) {
new SatNav();
}
}

Your problem is that you're treating the panel JPanel as if it has a BorderLayout when it doesn't. Rather it has JPanel's default FlowLayout which will size components to their preferred sizes (here [0, 0]) rather than have contained components fill the container. The simple solution: give your panel a BorderLayout:
panel = new JPanel(new BorderLayout());
Now when adding components, the BorderLayout constants will be respected by the container's layout.
Another and possibly better and more durable solution is to use a CardLayout to help you swap components.
For example:
import java.awt.CardLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class SatNav2 extends JPanel {
private static final long serialVersionUID = 1L;
// a publicly available example image for demonstration purposes:
public static final String SAT_PATH = "https://upload.wikimedia.org"
+ "/wikipedia/commons/1/18/AEHF_1.jpg";
private static final String INTRO_PANEL = "intro panel";
private static final String IMAGE_LABEL = "image label";
// our layout
private CardLayout cardLayout = new CardLayout();
// JLabel to display the image
private JLabel imgLabel = new JLabel();
public SatNav2(Image img) {
// put image into JLabel
imgLabel.setIcon(new ImageIcon(img));
// JPanel to hold JButton
JPanel introPanel = new JPanel();
// add button that does the swapping
introPanel.add(new JButton(new ShowImageAction("Show Image")));
// set the CardLayout and add the components. Order of adding
// is important since the first one is displayed
setLayout(cardLayout);
// add components w/ String constants
add(introPanel, INTRO_PANEL);
add(imgLabel, IMAGE_LABEL);
}
private class ShowImageAction extends AbstractAction {
public ShowImageAction(String text) {
super(text);
}
#Override
public void actionPerformed(ActionEvent e) {
// tell card layout to show next component
cardLayout.next(SatNav2.this);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
try {
createAndShowGui();
} catch (IOException e) {
e.printStackTrace();
}
});
}
private static void createAndShowGui() throws IOException {
// get the image
URL imgUrl = new URL(SAT_PATH);
Image img = ImageIO.read(imgUrl);
// pass image into our new JPanel
SatNav2 mainPanel = new SatNav2(img);
JFrame frame = new JFrame("Satellite");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}

How to switch JPanels in a JFrame from within the panel?

So, I'm trying to make a basic functional menu for a simple game. I tried to do this by creating 2 JPanels, one for the actual game, and another for my menu.
What I'm trying to do is have a button on my Menu panel that when pressed, switches the JPanel being displayed in the parent JFrame from that of the menu to that of the actual game.
Here is my code:
class Menu extends JPanel
{
public Menu()
{
JButton startButton = new JButton("Start!");
startButton.addActionListener(new Listener());
add(startButton);
}
private class Listener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
Container container = getParent();
Container previous = container;
System.out.println(getParent());
while (container != null)
{
previous = container;
container = container.getParent();
}
previous.setContentPane(new GamePanel());
}
}
}
As you can see, I created a Listener for my start button. Inside the listener, I used a while loop to get to the JFrame, via the getParent() method. The program is getting the JFrame object, however it's not letting me call the setContentPane method...
Does anyone know how to get this to work, or a better way to switch back and forth between a menu and game?

Like so :
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class CardLayoutDemo extends JFrame {
public final String YELLOW_PAGE = "yellow page";
public final String RED_PAGE = "red page";
private final CardLayout cLayout;
private final JPanel mainPane;
boolean isRedPaneVisible;
public CardLayoutDemo(){
setTitle("Card Layout Demo");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
mainPane = new JPanel();
mainPane.setPreferredSize(new Dimension(250,150));
cLayout = new CardLayout();
mainPane.setLayout(cLayout);
JPanel yellowPane = new JPanel();
yellowPane.setBackground(Color.YELLOW);
JPanel redPane = new JPanel();
redPane.setBackground(Color.RED);
mainPane.add(YELLOW_PAGE, yellowPane);
mainPane.add(RED_PAGE, redPane);
showRedPane();
JButton button = new JButton("Switch Panes");
button.addActionListener(e -> switchPanes() );
setLayout(new BorderLayout());
add(mainPane,BorderLayout.CENTER);
add(button,BorderLayout.SOUTH);
pack();
setVisible(true);
}
void switchPanes() {
if (isRedPaneVisible) {showYelloPane();}
else { showRedPane();}
}
void showRedPane() {
cLayout.show(mainPane, RED_PAGE);
isRedPaneVisible = true;
}
void showYelloPane() {
cLayout.show(mainPane, YELLOW_PAGE);
isRedPaneVisible = false;
}
public static void main(String[] args) {
new CardLayoutDemo();
}
}

How can I replace one JPanel with another JPanel in the same position?

I have a JFrame with about four frames. After a given action I want to replace one panel with another in the same position. My method for switching them looks like this (the this object is a class which extends JFrame):
public void switchPanel(){
mainPanel.remove(introPanel);
mainPanel.add(questionPanel);
this.repaint();
}
The original creation of the window looks like this:
mainPanel.add(titlePanel);
mainPanel.add(sidePanel);
mainPanel.add(introPanel);

You ask:
How can I replace one JPanel with another JPanel in the same position?
Very easily: use a CardLayout as this tool was built for just this situation.
If you had the following constants:
public static final String INTRO_PANEL = "intro panel";
public static final String QUESTION_PANEL = "question panel";
and added your JPanel's like so
mainPanel.setLayout(cardLayout);
mainPanel.add(introPanel, INTRO_PANEL);
mainPanel.add(questionPanel, QUESTION_PANEL);
cardLayout.show(mainPanel, INTRO_PANEL);
Then you could swap JPanels with:
cardLayout.show(mainPanel, QUESTION_PANEL);
would be all that were needed to show the swap, assuming that QUESTION_PANEL is a String constant that was used when you added the questionPanel to the mainPanel, and that the mainPanel uses the CardLayout.
For example:
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.*;
public class SwapPanels extends JPanel {
public static final String INTRO_PANEL = "intro panel";
public static final String QUESTION_PANEL = "question panel";
private static final int PREF_W = 500;
private static final int PREF_H = 400;
private CardLayout cardLayout = new CardLayout();
private JPanel introPanel;
private JPanel questionPanel;
private Random random = new Random();
public SwapPanels() {
introPanel = createPanel("Introduction");
questionPanel = createPanel("Question");
setLayout(cardLayout);
add(introPanel, INTRO_PANEL);
add(questionPanel, QUESTION_PANEL);
int delay = 3 * 1000; // show intro for 3 seconds
new Timer(delay, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
cardLayout.show(SwapPanels.this, QUESTION_PANEL);
((Timer) e.getSource()).stop();
}
}).start();
}
private JPanel createPanel(String title) {
int rgb = random.nextInt();
Color color = new Color(rgb);
JPanel panel = new JPanel(new GridBagLayout());
panel.setBorder(BorderFactory.createLineBorder(color, 60));
panel.add(new JLabel(title));
return panel;
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
SwapPanels mainPanel = new SwapPanels();
JFrame frame = new JFrame("SwapPanels");
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(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

after the remove method you have to run the validate method that's all. The code will be like this:
public void switchPanel(){
mainPanel.remove(introPanel);
mainPanel.add(questionPanel);
mainPanel.validate();
}
I hope that helps. Salam

Convert String into Component name in Java

I searched StackOverflow and found this question but I couldn't get it.
How do I invoke a Java method when given the method name as a string?
I have some JLabels and JPanels and each Label is working as a custom graphical button to change background color of a particular JPanel and as there are alot of these labels so I have created a custom MouseListener which is to change the background color of particular JPanel with the name each JLabel has.
Now as these JLabels are giving name of calling JPanels in String value, I want something like this
#Override
public void mouseClicked(MouseEvent e)
{
e.getComponent().getName().setBackground(new COLOR.RED);
}
But I cannot do so.
I just want to convert my string into JPanel's name.

You can use "client properties" from JComponent. Each Jcomponent contains a Map to put properties inside. You can use a constant String like "associatedPanel" for the key, and the JPanel for the value.
The code could be something like this:
JPanel panel1 = new JPanel();
JLabel label1 = new JLabel();
label1.putClientProperty("associatedPanel", panel1);
Now in the mouse listener use getClientProperty("associatedPanel") to obtain the associated panel to set the background.

You can do it like this:
create a map:
Map<String, JPanel> map = new HashMap<String, JPanel>();
then put all your jPanels in it using their names as keys:
map.put("jPanel1", jPanel1);
Then in the event listener:
JPanel jPanel1 = map.get(e.getComponent().getName());

I would say that the simplest solution to associate 2 elements of the UI is to combine them into a class. Then referencing the corresponding element from the other becomes obvious.
Something like:
class LabelPanel {
JLabel label;
JPanel pane;
...
}
Basic working example:
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestLabelPanelComposition {
public static class LabelPanel {
private final JLabel label;
private final JPanel panel;
private Color colorToSet;
public LabelPanel(String labelText, final Color colorToSet) {
super();
this.colorToSet = colorToSet;
this.label = new JLabel(labelText);
this.panel = new JPanel();
label.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
Color old= panel.getBackground();
panel.setBackground(LabelPanel.this.colorToSet);
LabelPanel.this.colorToSet = old;
}
});
}
public JLabel getLabel() {
return label;
}
public JPanel getPanel() {
return panel;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestLabelPanelComposition().initUI();
}
});
}
protected void initUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Random r= new Random();
List<LabelPanel> labelPanels =new ArrayList<TestLabelPanelComposition.LabelPanel>();
for(int i=0;i<10;i++) {
LabelPanel labelPanel = new LabelPanel("My Label to click "+(i+1), new Color(r.nextInt(256),r.nextInt(256),r.nextInt(256)));
labelPanel.getPanel().add(new JLabel("Some dummy text inside panel "+(i+1)));
labelPanels.add(labelPanel);
}
frame.setLayout(new GridLayout(0, 5));
for (LabelPanel labelPanel : labelPanels) {
frame.add(labelPanel.getLabel());
}
for (LabelPanel labelPanel : labelPanels) {
frame.add(labelPanel.getPanel());
}
frame.pack();
frame.setVisible(true);
}
}
This should not be too hard to adapt to your actual situation .

Composition vs inheritence in JButton

I'd like to create a simple table game by Swing. I have a JFrame and a JPanel variable.
I want to add JButtons to this JPanel, but I'd like to create an own class.
I made a class that extends JButton (inheritence):
public class GameField extends JButton {...}
So I could add GameFields to the JPanel.
But I'd like to create GameFields by composition:
public class GameField{
private JButton button;
}
But in this clase how I can add GameField to JPanel?
Can I solve this problem by compisition?

But in this clase how I can add GameField to JPanel? Can I solve this
problem by compisition?
You do this by adding a simple getter like this:
public class GameField{
private JButton button;
public GameField(String text) {
button = new JButton(text);
// do your stuff here
}
public JButton getButton() {
return button;
}
}
Then in your GUI:
public void createAndShowGUI() {
JPanel panel = new JPanel(new GridLayout(5,5));
panel.add(new GameField("Button # 1").getButton());
panel.add(new GameField("Button # 2").getButton());
...
JFrame frame = new JFrame("Game");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
Edit
You've stated in a comment:
Thanks, but in this case if I'd like to access this field (i.e.
panel.getComponent(i)), I can get only a JButton, and not a GameField.
You can keep a list with your GameField objects or you can use putClientProperty() method to keep a reference to the GameField object as shown in the example below:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Demo {
private void createAndShowGUI() {
ActionListener actionListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JButton button = (JButton)e.getSource();
GameField gameField = (GameField)button.getClientProperty("GameField");
if(gameField != null) {
System.out.println(gameField.getText());
}
}
};
GameField gameField1 = new GameField("Button # 1");
gameField1.getButton().addActionListener(actionListener);
GameField gameField2 = new GameField("Button # 2");
gameField2.getButton().addActionListener(actionListener);
JPanel content = new JPanel(new GridLayout());
content.add(gameField1.getButton());
content.add(gameField2.getButton());
JFrame frame = new JFrame("Demo");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(content);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
class GameField {
private String text;
private JButton button;
public GameField(String text) {
this.text = text;
button = new JButton(text);
button.putClientProperty("GameField", GameField.this);
}
public JButton getButton() {
return button;
}
public String getText() {
return text;
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Demo().createAndShowGUI();
}
});
}
}

If you wish your GameField objects to have JComponents and still be able to add them to other JComponents, have them extend JPanel instead of JButton.
You can then have your GameField objects as JPanels with other JComponents and add them to your JFrame.