Java Drag and Drop on Windows Vista/7

843807

hi! im trying to get simple drag and drop behaviour on windows vista and windows 7 but it seems it doesnt work. im trying to drag an image file into a JFormattedTextField that has default DnD behaviour so i can get the path on the field. im using a very simple piece of code. it works on ubuntu linux, but it seems that the same code just dont work on windows 7 and windows vista. heres the code

public class DnDTest{
public static void main(String[] args){
JFrame frame = new JFrame();
JFormattedTextField field = new JFormattedTextField();
field.setPreferredSize(new Dimension(100,30));
frame.getContentPane().add(field);
frame.pack();
frame.setVisible(true);
}
}

i run it, then drag an image from windows desktop on the field component but the drop doesnt happen. when i do the same on ubuntu it works. im running it from netbeans 6.9 and using jdk1.6_20. thanks in advance!

darrylburke

Note: This thread was originally posted in the [Java Programming|http://forums.sun.com/forum.jspa?forumID=31] forum, but moved to this forum for closer topic alignment.

843807

I think you will need a DropTargetListener for Windows Systems - see example:

import java.awt.*;
import javax.swing.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
import java.io.*;

class DnDTest
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame();
        JFormattedTextField field = new JFormattedTextField();

        new DropTarget(field, new TextDropTargetListener(field));

        field.setPreferredSize(new Dimension(100,30));
        frame.getContentPane().add(field);
        frame.pack();
        frame.setVisible(true);
    }
}

class TextDropTargetListener implements DropTargetListener
{
    public TextDropTargetListener(JTextField aTextField)
    {
        textField = aTextField;
    }

    public void dragEnter(DropTargetDragEvent event)
    {
        if(!isDragAcceptable(event))
        {
            event.rejectDrag();
            return;
        }
    }

    public void dragExit(DropTargetEvent event)
    {
    }

    public void dragOver(DropTargetDragEvent event)
    {
    }

    public void dropActionChanged(DropTargetDragEvent event)
    {
        if(!isDragAcceptable(event))
        {
            event.rejectDrag();
            return;
        }
    }

    public void drop(DropTargetDropEvent event)
    {
        if(!isDropAcceptable(event))
        {
            event.rejectDrop();
            return;
        }

        event.acceptDrop(DnDConstants.ACTION_COPY);

        Transferable transferable = event.getTransferable();
        DataFlavor[] flavors = transferable.getTransferDataFlavors();
        DataFlavor d = flavors[0];
        try
        {
            if(d.equals(DataFlavor.javaFileListFlavor))
            {
                java.util.List<File> fileList = (java.util.List<File>) transferable.getTransferData(d);
                textField.setText(fileList.get(0).toString());
            }
            else if(d.equals(DataFlavor.stringFlavor))
            {
                String s = (String) transferable.getTransferData(d);
                textField.setText(s);
            }
        }
        catch(Exception e)
        {
            textField.setText(e.toString());
        }
        event.dropComplete(true);
    }

    public boolean isDragAcceptable(DropTargetDragEvent event)
    {
        return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0;
    }

    public boolean isDropAcceptable(DropTargetDropEvent event)
    {
        return (event.getDropAction() & DnDConstants.ACTION_COPY_OR_MOVE) != 0;
    }

    private JTextField textField;
}

Of course you would need to modify this for multiple selections

That is how I usually deal with DnD files

843807

it worked! thanks a lot, its just a little weird that you can get default drag and drop behaviour on linux but not in windows. thanks again!