创建带有背景图像的表单 (JLayeredPane)

Also, before anyone jumps all over me, you could use a JLabel as the background component, setting a layout manager on it and adding your components to it, but the JLabel doesn't calculate it's required size based on the child components it contains, but instead, uses the icon and text properties. This might not be an issue if your background image is sufficiently big enough, but always seems like a weak point waiting to break.

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GridBagLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;

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() {
            setLayout(new BorderLayout());
            BackgroundPane bgPane = new BackgroundPane();
            bgPane.setLayout(new GridBagLayout());
            add(bgPane);

            try {
                BufferedImage bg = ImageIO.read(new File("C:\Users\shane\Dropbox\MegaTokyo\thumnails\megatokyo_omnibus_1_3_cover_by_fredrin-d4oupef.jpg"));
                bgPane.setBackgroundImage(bg);
            } catch (IOException ex) {
                ex.printStackTrace();
            }

            JLabel show = new JLabel("Bananas are yellow");
            show.setOpaque(true);
            show.setForeground(Color.RED);
            show.setBackground(Color.YELLOW);
            show.setBorder(new EmptyBorder(20, 20, 20, 20));
            bgPane.add(show);

        }

    }

    public class BackgroundPane extends JPanel {

        private BufferedImage img;

        @Override
        public Dimension getPreferredSize() {
            BufferedImage img = getBackgroundImage();

            Dimension size = super.getPreferredSize();
            if (img != null) {
                size.width = Math.max(size.width, img.getWidth());
                size.height = Math.max(size.height, img.getHeight());
            }

            return size;
        }

        public BufferedImage getBackgroundImage() {
            return img;
        }

        public void setBackgroundImage(BufferedImage value) {
            if (img != value) {
                BufferedImage old = img;
                img = value;
                firePropertyChange("background", old, img);
                revalidate();
                repaint();
            }
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            BufferedImage bg = getBackgroundImage();
            if (bg != null) {
                int x = (getWidth() - bg.getWidth()) / 2;
                int y = (getHeight() - bg.getHeight()) / 2;
                g.drawImage(bg, x, y, this);
            }
        }

    }

}

这个实现缺少像自动缩放或重复这样的东西，但你明白了