Ajouter des vignettes d'images à une mise en page dans une grille

Problème?:

Vous devez ajoutez une collection d'images sous forme de petites vignettes à un cadre dans un SpringLayout et affichez-les sous forme de grille dans un volet de défilement. La liste des photos peut être longue, nécessitant un volet de défilement.

Solution?:

Pour y parvenir à l'aide de Swing, suivez ces étapes?:

1. Créez un JPanel pour les photos et un JScrollPane pour le JPanel.
2. Utilisez un gestionnaire de mise en page comme FlowLayout pour organiser les vignettes de manière enveloppante pour faciliter la visualisation et le défilement.
3. Ajoutez chaque vignette en tant que JPanel avec l'image mise à l'échelle de manière appropriée.
4. Ajoutez le JScrollPane au cadre et ajustez son taille et position à l'aide des contraintes SpringLayout.

Vous trouverez ci-dessous un exemple de code illustrant le solution?:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class ImageGrid {

    public static void main(String[] args) {
        new ImageGrid();
    }

    public ImageGrid() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Image Grid");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());

                // Create a JPanel for the photos and add it to a JScrollPane
                JPanel photoPanel = new JPanel(new WrapLayout());
                JScrollPane photoScroll = new JScrollPane(photoPanel);

                // Add the JScrollPane to the frame
                frame.add(photoScroll, BorderLayout.CENTER);

                // Create a button to scan and add the thumbnails
                JButton scanButton = new JButton("Scan");
                scanButton.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        // Scan for image files
                        String path = "Enter path to your image directory";
                        File[] files = new File(path).listFiles(new FileFilter() {
                            @Override
                            public boolean accept(File pathname) {
                                String name = pathname.getName().toLowerCase();
                                return pathname.isFile() && (name.endsWith(".png")
                                        || name.endsWith(".jpg")
                                        || name.endsWith(".gif"));
                            }
                        });

                        photoPanel.removeAll();
                        for (File file : files) {
                            try {
                                // Load and scale the image
                                ImagePane pane = new ImagePane(file);
                                photoPanel.add(pane);
                            } catch (Exception exp) {
                                exp.printStackTrace();
                            }
                        }
                        photoPanel.revalidate();
                        photoPanel.repaint();
                    }
                });

                // Add the scan button to the frame
                frame.add(scanButton, BorderLayout.SOUTH);

                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setResizable(true);
                frame.setVisible(true);
            }
        });
    }

    public class ImagePane extends JPanel {

        private Image img;

        public ImagePane(File source) throws IOException {
            img = ImageIO.read(source);
            if (img.getWidth(this) > 200 || img.getHeight(this) > 200) {
                int width = img.getWidth(this);
                int height = img.getWidth(this);
                float scaleWidth = 200f / width;
                float scaleHeight = 200f / height;
                if (scaleWidth > scaleHeight) {
                    width = -1;
                    height = (int)(height * scaleHeight);
                } else {
                    width = (int)(width * scaleWidth);
                    height = -1;
                }
                img = img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            if (img != null) {
                // Draw the scaled image
                int x = (getWidth() - img.getWidth(this)) / 2;
                int y = (getHeight() - img.getHeight(this)) / 2;
                g2d.drawImage(img, x, y, this);
            }
            g2d.dispose();
        }
    }

    /**
     * FlowLayout subclass that fully supports wrapping of components.
     */
    public class WrapLayout extends FlowLayout {

        private Dimension preferredLayoutSize;

        /**
         * Constructs a new
         * <code>WrapLayout</code> with a left alignment and a default 5-unit
         * horizontal and vertical gap.
         */
        public WrapLayout() {
            super();
        }

        /**
         * Constructs a new
         * <code>FlowLayout</code> with the specified alignment and a default 5-unit
         * horizontal and vertical gap. The value of the alignment argument must be
         * one of
         * <code>WrapLayout</code>,
         * <code>WrapLayout</code>, or
         * <code>WrapLayout</code>.
         *
         * @param align the alignment value
         */
        public WrapLayout(int align) {
            super(align);
        }

        /**
         * Creates a new flow layout manager with the indicated alignment and the
         * indicated horizontal and vertical gaps.
         * <p>
         * The value of the alignment argument must be one of
         * <code>WrapLayout</code>,
         * <code>WrapLayout</code>, or
         * <code>WrapLayout</code>.
         *
         * @param align the alignment value
         * @param hgap the horizontal gap between components
         * @param vgap the vertical gap between components
         */
        public WrapLayout(int align, int hgap, int vgap) {
            super(align, hgap, vgap);
        }

        /**
         * Returns the preferred dimensions for this layout given the
         * <i>visible</i> components in the specified target container.
         *
         * @param target the component which needs to be laid out
         * @return the preferred dimensions to lay out the subcomponents of the
         * specified container
         */
        @Override
        public Dimension preferredLayoutSize(Container target) {
            return layoutSize(target, true);
        }

        /**
         * Returns the minimum dimensions needed to layout the <i>visible</i>
         * components contained in the specified target container.
         *
         * @param target the component which needs to be laid out
         * @return the minimum dimensions to lay out the subcomponents of the
         * specified container
         */
        @Override
        public Dimension minimumLayoutSize(Container target) {
            Dimension minimum = layoutSize(target, false);
            minimum.width -= (getHgap() + 1);
            return minimum;
        }

        /**
         * Returns the minimum or preferred dimension needed to layout the target
         * container.
         *
         * @param target target to get layout size for
         * @param preferred should preferred size be calculated
         * @return the dimension to layout the target container
         */
        private Dimension layoutSize(Container target, boolean preferred) {
            synchronized (target.getTreeLock()) {
                //  Each row must fit with the width allocated to the container.
                //  When the container width = 0, the preferred width of the container

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