Setting background images in JFrame

Question

There is no built-in method, but there are several ways to do it. The most straightforward way that I can think of at the moment is:

1. Create a subclass of JComponent.
2. Override the paintComponent(Graphics g) method to paint the image that you want to display.
3. Set the content pane of the JFrame to be this subclass.

Some sample code:

class ImagePanel extends JComponent {
    private Image image;
    public ImagePanel(Image image) {
        this.image = image;
    }
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, this);
    }
}

// elsewhere
BufferedImage myImage = ImageIO.read(...);
JFrame myJFrame = new JFrame("Image pane");
myJFrame.setContentPane(new ImagePanel(myImage));

Note that this code does not handle resizing the image to fit the JFrame, if that's what you wanted.

Try this :

import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;


public class Test {

    public static void main(String[] args) {
        JFrame f = new JFrame();
        try {
            f.setContentPane(new JLabel(new ImageIcon(ImageIO.read(new File("test.jpg")))));
        } catch (IOException e) {
            e.printStackTrace();
        }
        f.pack();
        f.setVisible(true);
    }

}

By the way, this will result in the content pane not being a container. If you want to add things to it you have to subclass a JPanel and override the paintComponent method.

You can use the Background Panel class. It does the custom painting as explained above but gives you options to display the image scaled, tiled or normal size. It also explains how you can use a JLabel with an image as the content pane for the frame.