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| 14. 112. 3. 拖放图片 |
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To transfer something other than a simple property, you need to create an
implementation of the Transferable interface, |
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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);
}
}
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