ImageSelection.java Source code

Introduction

Here is the source code for ImageSelection.java

Source

import java.awt.BorderLayout;
import java.awt.Image;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.io.IOException;

import javax.swing.AbstractButton;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.TransferHandler;

class ImageSelection extends TransferHandler implements Transferable {

    private static final DataFlavor flavors[] = { DataFlavor.imageFlavor };

    private Image image;

    public int getSourceActions(JComponent c) {
        return TransferHandler.COPY;
    }

    public boolean canImport(JComponent comp, DataFlavor flavor[]) {
        if (!(comp instanceof JLabel) && !(comp instanceof AbstractButton)) {
            return false;
        }
        for (int i = 0, n = flavor.length; i < n; i++) {
            for (int j = 0, m = flavors.length; j < m; j++) {
                if (flavor[i].equals(flavors[j])) {
                    return true;
                }
            }
        }
        return false;
    }

    public Transferable createTransferable(JComponent comp) {
        // Clear
        image = null;

        if (comp instanceof JLabel) {
            JLabel label = (JLabel) comp;
            Icon icon = label.getIcon();
            if (icon instanceof ImageIcon) {
                image = ((ImageIcon) icon).getImage();
                return this;
            }
        } else if (comp instanceof AbstractButton) {
            AbstractButton button = (AbstractButton) comp;
            Icon icon = button.getIcon();
            if (icon instanceof ImageIcon) {
                image = ((ImageIcon) icon).getImage();
                return this;
            }
        }
        return null;
    }

    public boolean importData(JComponent comp, Transferable t) {
        if (comp instanceof JLabel) {
            JLabel label = (JLabel) comp;
            if (t.isDataFlavorSupported(flavors[0])) {
                try {
                    image = (Image) t.getTransferData(flavors[0]);
                    ImageIcon icon = new ImageIcon(image);
                    label.setIcon(icon);
                    return true;
                } catch (UnsupportedFlavorException ignored) {
                } catch (IOException ignored) {
                }
            }
        } else if (comp instanceof AbstractButton) {
            AbstractButton button = (AbstractButton) comp;
            if (t.isDataFlavorSupported(flavors[0])) {
                try {
                    image = (Image) t.getTransferData(flavors[0]);
                    ImageIcon icon = new ImageIcon(image);
                    button.setIcon(icon);
                    return true;
                } catch (UnsupportedFlavorException ignored) {
                } catch (IOException ignored) {
                }
            }
        }
        return false;
    }

    // Transferable
    public Object getTransferData(DataFlavor flavor) {
        if (isDataFlavorSupported(flavor)) {
            return image;
        }
        return null;
    }

    public DataFlavor[] getTransferDataFlavors() {
        return flavors;
    }

    public boolean isDataFlavorSupported(DataFlavor flavor) {
        return flavors[0].equals(flavor);
    }
}

public class DragImage {
    public static void main(String args[]) {
        JFrame frame = new JFrame("Drag Image");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Icon icon = new ImageIcon("yourFile.gif");
        JLabel label = new JLabel(icon);
        label.setTransferHandler(new ImageSelection());
        MouseListener listener = new MouseAdapter() {
            public void mousePressed(MouseEvent me) {
                JComponent comp = (JComponent) me.getSource();
                TransferHandler handler = comp.getTransferHandler();
                handler.exportAsDrag(comp, me, TransferHandler.COPY);
            }
        };
        label.addMouseListener(listener);
        frame.add(new JScrollPane(label), BorderLayout.CENTER);

        frame.setSize(300, 150);
        frame.setVisible(true);
    }
}