I have two JPanels layered on top of each other in the same container. I am using container.add(jpanel, 0); and container.add(otherjpanel, 1). It works fine however in order for the top layer to show I have to hover over the components with the mouse.
Here is some executable code showing my problem.
Just hover mouse on upper part of screen.
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.event.*;
import javax.swing.*;
import javax.swing.text.*;
import java.io.*;
import java.util.*;
public class test {
public static void main(String args[]) {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
} catch (Exception e) {
}
JFrame frame = new GUIframe();
frame.setVisible(true);
frame.setResizable(false);
}
}
class GUIframe extends JFrame{
public GUIframe(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setPreferredSize(new Dimension(300,400));
setSize(300, 400);
JLayeredPane content = new JLayeredPane();
content.setPreferredSize(new Dimension(300,400));
content.setSize(300,400);
JPanel board = new JPanel();
for (int i = 0;i<5;i++){
JButton button = new JButton("button");
board.add(button);
}
content.add(new ImagePanel());
this.add(content);
this.add(board);
}
}
class ImagePanel extends JPanel {
private Image img;
String imageLocation = "image location here";
ImagePanel() {
img = new ImageIcon(imageLocation).getImage();
setPreferredSize(new Dimension(300,400));
setSize(300,400);
setLayout(null);
setOpaque(false);
}
public void paint(Graphics g){
super.paint(g);
g.drawImage(img, 0, 0, this);
}
}
A contentPane's layout is by default BorderLayout. Have you changed this? Perhaps you should set your contentPane to be a JLayeredPane instead.
If anything about this recommendation is unclear, please leave a comment.
Edit 1: Example of JLayeredPane
You could solve this sort of thing with a layered pane as I described, something like listed below, but you must take care to set size and to make overlying JPanels non-opaque:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Test2 {
private static final int LP_WIDTH = 450;
private static final int LP_HEIGHT = 600;
private static final String IMAGE_SITE = "http://upload.wikimedia.org/wikipedia/"
+ "commons/thumb/b/b8/Laser_Towards_Milky_Ways_Centre.jpg/"
+ "660px-Laser_Towards_Milky_Ways_Centre.jpg";
private JLayeredPane layeredPanel = new JLayeredPane();
public Test2() {
layeredPanel.setPreferredSize(new Dimension(LP_WIDTH, LP_HEIGHT));
try {
URL url = new URL(IMAGE_SITE);
BufferedImage image = ImageIO.read(url);
ImagePanel2 imagePanel2 = new ImagePanel2(image);
imagePanel2.setSize(layeredPanel.getPreferredSize());
JPanel buttonPanel = new JPanel();
buttonPanel.setOpaque(false);
for (int i = 0; i < 8; i++) {
buttonPanel.add(new JButton("Button"));
}
buttonPanel.setSize(layeredPanel.getPreferredSize());
layeredPanel.add(imagePanel2, JLayeredPane.DEFAULT_LAYER);
layeredPanel.add(buttonPanel, JLayeredPane.PALETTE_LAYER);
} catch (MalformedURLException e) {
e.printStackTrace();
System.exit(-1);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
}
private JComponent getMainComponent() {
return layeredPanel;
}
private static void createAndShowGui() {
Test2 test2 = new Test2();
JFrame frame = new JFrame("Test2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(test2.getMainComponent());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class ImagePanel2 extends JPanel {
private Image image;
public ImagePanel2(Image image) {
this.image = image;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
g.drawImage(image, 0, 0, null);
}
}
}
However if all you want is a background image, then that's what I'd do, create a JPanel that uses a background image, and then add stuff to it.
import java.awt.*;
import java.awt.image.*;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Test3 extends JPanel {
private static final int LP_WIDTH = 450;
private static final int LP_HEIGHT = 600;
private static final String IMAGE_SITE = "http://upload.wikimedia.org/wikipedia/"
+ "commons/thumb/b/b8/Laser_Towards_Milky_Ways_Centre.jpg/"
+ "660px-Laser_Towards_Milky_Ways_Centre.jpg";
private BufferedImage image;
public Test3() {
try {
URL url = new URL(IMAGE_SITE);
image = ImageIO.read(url);
for (int i = 0; i < 8; i++) {
add(new JButton("Button"));
}
} catch (MalformedURLException e) {
e.printStackTrace();
System.exit(-1);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
}
@Override
public Dimension getPreferredSize() {
return new Dimension(LP_WIDTH, LP_HEIGHT);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
g.drawImage(image, 0, 0, null);
}
}
private static void createAndShowGui() {
Test3 mainPanel = new Test3();
JFrame frame = new JFrame("Test3");
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();
}
});
}
}