Drop support only works on the second drop

Question

Hi,
I created an ImageComponent that accepts drops and displays images. The problem I'm facing is that the drop is only accepted on the second try. For some reason the getDataFlavors() method on the TransferSupport returns an empty array on the first drop.
I'm dropping a JPG file from the desktop on my ImageComponent. I'm running it in debug mode with the latest version of Eclipse on Mac OS X 10.6.
I hope someone can help me solve this problem.
Thanks in advance,
Stef
Here is my source code:
public class ImageComponent extends JComponent {
     private static final long serialVersionUID = 1L;
     private BufferedImage image;
     private final Vector<ImageChangeListener> listeners = new Vector<ImageChangeListener>();
     public ImageComponent() {
          setTransferHandler(new ImageTransferHandler());
     public synchronized void addImageChangeListener(ImageChangeListener listener) {
          listeners.add(listener);
     public synchronized void removeImageChangeListener(ImageChangeListener listener) {
          listeners.remove(listener);
     public void setImage(BufferedImage image) {
          this.image = image;
          paint(getGraphics());
     @Override
     public Dimension getPreferredSize() {
          if (image != null) {
               BufferedImage scaledImage = Utils.scaleImage(image, getWidth(), getHeight());
               return new Dimension(scaledImage.getWidth(), scaledImage.getHeight());
          } else {
               return super.getPreferredSize();
     @Override
     public void paint(Graphics g) {
          if (g != null) {
               g.clearRect(0, 0, getWidth(), getHeight());
               super.paint(g);
               if (image != null) {
                    BufferedImage scaledImage = Utils.scaleImage(image, getWidth(), getHeight());
                    int x = ((getWidth() - scaledImage.getWidth()) / 2);
                    int y = ((getHeight() - scaledImage.getHeight()) / 2);
                    g.drawImage(scaledImage, x, y, null);
     private void fireImageChange() {
          ImageChangeEvent event = new ImageChangeEvent(this, image);
          for (ImageChangeListener listener : listeners) {
               listener.imageChanged(event);
          setImage(image);
     private class ImageTransferHandler extends TransferHandler {
          @Override
          public boolean canImport(TransferSupport support) {
               for (DataFlavor dataFlavor : support.getDataFlavors()) { // Returns an empty array on the first drop
                    System.out.println(dataFlavor);
               return support.isDataFlavorSupported(DataFlavor.javaFileListFlavor); // returns false on the first drop, true on consecutive drops
          @Override
          public boolean importData(TransferSupport support) {
               if (canImport(support)) {
                    BufferedImage newImage = readFirstImage(support);
                    if (newImage != null) {
                         setImage(newImage);
                         fireImageChange();
                         return true;
                    } else {
                         return false;
               } else {
                    return false;
          private BufferedImage readFirstImage(TransferSupport support) {
               try {
                    List<File> fileList = (List<File>) support.getTransferable().getTransferData(
                              DataFlavor.javaFileListFlavor);
                    if (fileList != null && fileList.size() > 0) {
                         File file = fileList.get(0);
                         return ImageIO.read(file);
                    } else {
                         return null;
               catch (IIOException exception) {
                    return null;
               catch (IOException exception) {
                    exception.printStackTrace();
                    return null;
               catch (UnsupportedFlavorException exception) {
                    return null;
               catch (Exception e) {
                    return null;
}

Answer 1

I'm on a relatively new system, where I haven't set much up, but I don't get any package-name completion which highlights the point that this is shell (and shell config) dependent.  What shell are you using?  Have you done anything to configure completion?  Do you have any pacman related aliases (or functions)?
I do, by default bash settings it seems, get filename completion with pacman -R, so the options are files in the current directory.
EDIT: (duh) just installing bash-completion now - new results momentarily - but more on point, this further highlghts the shell + config dependent nature of this.  EDIT2: works as expected with bash-completion installed.
Last edited by Trilby (2013-07-15 21:58:12)