Drag a File to System (VLC)

Question

Hi,
I want to drag a file from a Java Application from a JButton to a VLC Player outside the application, so it will be played in VLC. The application knows the path. I use a button to have some area that is easy and fast to hit.
To add drag functionallity to a button I use the drag source examples from www.java2s.com/Code/Java/Swing-JFC/JLabelDragSource.htm. I made some minor changes to support a button and now I can drag easily a string (the path). But VLC seems not to accept a string. So I think I have to use the javaFileListFlavor as the mime type.
The example I mentioned uses explicit a class for a DragSource and a rewritten Transferable class. I think to add javaFileListFlavor behaviour it is nessecary to add this to the Transferable class. But I don't really understand some things in the coding, escpecially at the end of the class. Here is my current code:
import java.awt.Font;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceDropEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Iterator;
import javax.swing.*;
class JButtonTransferable implements Transferable {
     GeneralEnvironment genE;
     public JButtonTransferable(JButton button, GeneralEnvironment genE) {
          this.button = button;
          this.genE = genE;
     // Implementation of the Transferable interface
     public DataFlavor[] getTransferDataFlavors() {
          return flavors;
     public boolean isDataFlavorSupported(DataFlavor fl) {
          for (int i = 0; i < flavors.length; i++) {
               if (fl.equals(flavors)) {
                    return true;
          return false;
     public Object getTransferData(DataFlavor fl) {
          if (!isDataFlavorSupported(fl)) {
               return null;
          if (fl.equals(DataFlavor.stringFlavor)) {
               // String - return the text as a String
               //return button.getText() + " (DataFlavor.stringFlavor)";
               return genE.getClipDragString();
          } else if (fl.equals(jButtonFlavor)) {
               // The JButton itself - just return the button.
               return button;
          } else {
               // Plain text - return an InputStream
               try {
                    //String targetText = button.getText() + " (plain text flavor)";
                    String targetText = genE.getClipDragString(); // + " (plain text flavor)";
                    int length = targetText.length();
                    ByteArrayOutputStream os = new ByteArrayOutputStream();
                    OutputStreamWriter w = new OutputStreamWriter(os);
                    w.write(targetText, 0, length);
                    w.flush();
                    byte[] bytes = os.toByteArray();
                    w.close();
                    return new ByteArrayInputStream(bytes);
               } catch (IOException e) {
                    return null;
     // A flavor that transfers a copy of the JButton
     public static final DataFlavor jButtonFlavor = new DataFlavor(JButton.class, "Swing JLabel");
     private JButton button; // The button being transferred
     private static final DataFlavor[] flavors = new DataFlavor[] {
          DataFlavor.stringFlavor, new DataFlavor("text/plain; charset=ascii", "ASCII text"), jButtonFlavor
}The genE Object (GeneralEnvironment) is my own object that is capable to provide a current path as a string.
My problem is, that I don't know how to add javaFileListFlavor in this environment. I saw examples on javaFileListFlavor, but they have different classes they add and rewrite. Unfortunatly I can't bring them together. Anyone an idea?
- Frankie
Edited by: rebelman on Apr 11, 2010 3:00 AM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

Oho ... my fault. Solved
I was not recognizing that the last line of code was a simple init of an array. When I found out that this is the case it was simple to add file drag support. The main changes are here. The array init is now formatted different:
     public Object getTransferData(DataFlavor fl) {
          if (!isDataFlavorSupported(fl)) {
               return null;
          if (fl.equals(DataFlavor.stringFlavor)) {
               // String - return the text as a String
               //return button.getText() + " (DataFlavor.stringFlavor)";
               return genE.getClipDragString();
          } else if (fl.equals(jButtonFlavor)) {
               // The JButton itself - just return the button.
               return button;
          } else if (fl.equals(DataFlavor.javaFileListFlavor)) {
               Vector<File> files = new Vector<File>(1,1);
               files.add( new File(genE.getClipDragString()) );
               return files;
          } else {
               // Plain text - return an InputStream
               try {
                    //String targetText = button.getText() + " (plain text flavor)";
                    String targetText = genE.getClipDragString(); // + " (plain text flavor)";
                    int length = targetText.length();
                    ByteArrayOutputStream os = new ByteArrayOutputStream();
                    OutputStreamWriter w = new OutputStreamWriter(os);
                    w.write(targetText, 0, length);
                    w.flush();
                    byte[] bytes = os.toByteArray();
                    w.close();
                    return new ByteArrayInputStream(bytes);
               } catch (IOException e) {
                    return null;
     // A flavor that transfers a copy of the JButton
     public static final DataFlavor jButtonFlavor = new DataFlavor(JButton.class, "Swing JLabel");
     private JButton button; // The button being transferred
     private static final DataFlavor[] flavors = new DataFlavor[] {
          DataFlavor.stringFlavor,
          DataFlavor.javaFileListFlavor,
          new DataFlavor("text/plain; charset=ascii", "ASCII text"),
          jButtonFlavor
     };So know it workes and files (or pathes that I have in the app) can be easily dragged from a button to VLC player on windows (other OS'es I haven't testet.
Thanks for patience,
- Frankie