Drag and Drop(JList )

Hi there,
I have a problem with implementing Drag and Drop into my JList. As my class is a JPanel and there is a JList which is needed to have a drag and drop feature where it enable user to drag and drop to another JList. So I would like to ask how can i go about doin it without writing a new JList Class which implements the DropTargetListener, DragSourceListener, DragGestureListener to the JPanel.
Thanks...

JTextComponents have preinstalled TransferHandlers that make it possible to simply call setDragEnabled(true) and you are good to go. However, with most other components, you need to install a custom TransferHandler (ie call list.setTransferHandler() ) to get the job done.
Here is a sample of the code you need: ListTransferHandler
ICE

Similar Messages

JList - drag and drop

Hi,
I'm struggling with getting my program outfitted with a drag and drop function in and between a few JList components. (I'm using NetBeans IDE 6.7)
I have four JLists of which only one I want to enabled drag and drop rearrangement of the strings. Furthermore I would like to enable dragging from the other three lists into the rearrangeable list (which may be empty!).
I've searched for answers but I just can't manage to translate the answers on other forums into a usable solution for my program... I am relatively new to Java and NetBeans, so I would appreciate if you could keep the answers simple... (if possible).
What I know about this problem already:
- if i set dragEnabled to true, I can drag text into e.g. a TextField without further complications

JTextComponents have preinstalled TransferHandlers that make it possible to simply call setDragEnabled(true) and you are good to go. However, with most other components, you need to install a custom TransferHandler (ie call list.setTransferHandler() ) to get the job done.
Here is a sample of the code you need: ListTransferHandler
ICE

Drag and Drop issue in Jlist - Transferhandler not working

Hi all,
I have a problem associated with the drag and drop of components into a Jlist.
When I drag component out of a Jlist, the control reaches inside transfer handler, but when I try to insert a component into the Jlist, the control does not reach inside Jlist transfer handler.
     jlist.setDropMode(DropMode.INSERT);
     jlist.setDragEnabled(true);
     jlist.setTransferHandler(new TransferHandler()
               List fileList;
               boolean export = false;
               List<File> newList = null;
               protected Transferable createTransferable(JComponent c)
                    System.out.println("inside handler");
                                ..............................Please help me with this issue.
Any help in this regard will be well appreciated with dukes.
Regards,
Anees

AneesAhamed wrote:
Hi all,
I have a problem associated with the drag and drop of components into a Jlist.
When I drag component out of a Jlist, the control reaches inside transfer handler, but when I try to insert a component into the Jlist, the control does not reach inside Jlist transfer handler.
jlist.setDropMode(DropMode.INSERT);
jlist.setDragEnabled(true);
jlist.setTransferHandler(new TransferHandler()
               List fileList;
               boolean export = false;
               List<File> newList = null;
               protected Transferable createTransferable(JComponent c)
                    System.out.println("inside handler");
..............................Please help me with this issue.
Any help in this regard will be well appreciated with dukes.If you're wondering why your createTransferable() method is not called when you drag from some other component and drop into the list it is because createTransferable() is called when you start dragging. So it would be the TransferHandler of the source component, not your target list, that has its createTransferable() called in that case.
When the list is the target of a drag&drop you should see the canImport() method of your TransferHandler being called. Do a System.out(0 in that method as well and see if that is the case.

Drag and Drop items among JList

Hi,
I want to drag item from one JList and drop into another JList using JFrame in java Swing. Please provide me code for this.
Thanks
Nitin

You need to implement a drag-and-drop (dnd) behaviour between your swing components.
Like most programming tasks it looks harder than it really is. Basically you need a DragSource and a DropTarget with a Transferable object in between. This Transferable object is the object from your list.
Here is Sun's tutorial on it... http://java.sun.com/docs/books/tutorial/dnd/
Good luck.

Drag and Drop between Jlists

Hello,
I have two JLists, one containing music tracks (not actual tracks, just info like name, artist duration etc), and the other is a Playlist.
So I want to be able to drag items from the database of tracks (Jlist one) to the playlist (Jlist two).
I have looked how this is done and here is some of the code that I have:
    //allow the mouse to drag and drop tracks
    private class DragMouseAdapter extends MouseAdapter {
        public void mousePressed(MouseEvent e) {
            JComponent c = (JComponent)e.getSource();
            TransferHandler handler = c.getTransferHandler();
            handler.exportAsDrag(c, e, TransferHandler.COPY);
        //allow tracks to be dragged and dropped
        lstDatabase.setDragEnabled(true);
        MouseListener listener = new DragMouseAdapter();
        lstDatabase.addMouseListener(listener);
        //allow tracks to be dragged and dropped
        lstPlayList.addMouseListener(listener);
        lstPlayList.setTransferHandler(new TransferHandler("text"));Nothing seems to happen
Any Ideas?
Cheers

The swing tutorial on "How to Use Drag and Drop" has a working example using JLists:
http://java.sun.com/docs/books/tutorial/uiswing/misc/dnd.html#complex

How to handle (drag and drop) and Action Event in a JList?

I am having many JList,
On click of an element in JList I am loading a image in JSP.
But If I try to drag and drop one image from one bucket to another bucket Iam not getting any problem,
But I when I drag all the images from the target List to some other List and make the target List empty.
Now If I try to move the image from source list to the target list Iam getting this error,
Exception in thread "AWT-EventQueue-6" java.lang.NullPointerException
     at pdfViewer.NewFileSegregater$24.valueChanged(NewFileSegregater.java:1944)
     at javax.swing.JList.fireSelectionValueChanged(Unknown Source)
     at javax.swing.JList$ListSelectionHandler.valueChanged(Unknown Source)
     at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
     at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
     at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
     at javax.swing.DefaultListSelectionModel.insertIndexInterval(Unknown Source)
     at javax.swing.plaf.basic.BasicListUI$Handler.intervalAdded(Unknown Source)
     at javax.swing.AbstractListModel.fireIntervalAdded(Unknown Source)
     at javax.swing.DefaultListModel.addElement(Unknown Source)
     at pdfViewer.NewFileSegregater.actionPerformed(NewFileSegregater.java:2918)
     at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
     at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
     at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
     at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
     at javax.swing.plaf.basic.BasicButtonListener$Actions.actionPerformed(Unknown Source)
     at javax.swing.SwingUtilities.notifyAction(Unknown Source)
     at javax.swing.JComponent.processKeyBinding(Unknown Source)
     at javax.swing.KeyboardManager.fireBinding(Unknown Source)
     at javax.swing.KeyboardManager.fireKeyboardAction(Unknown Source)
     at javax.swing.JComponent.processKeyBindingsForAllComponents(Unknown Source)
     at javax.swing.JComponent.processKeyBindings(Unknown Source)
     at javax.swing.JComponent.processKeyEvent(Unknown Source)
     at java.awt.Component.processEvent(Unknown Source)
     at java.awt.Container.processEvent(Unknown Source)
     at java.awt.Component.dispatchEventImpl(Unknown Source)
     at java.awt.Container.dispatchEventImpl(Unknown Source)
     at java.awt.Component.dispatchEvent(Unknown Source)
     at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
     at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
     at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
     at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
     at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
     at java.awt.Component.dispatchEventImpl(Unknown Source)
     at java.awt.Container.dispatchEventImpl(Unknown Source)
     at java.awt.Component.dispatchEvent(Unknown Source)
     at java.awt.EventQueue.dispatchEvent(Unknown Source)
     at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
     at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
     at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
     at java.awt.EventDispatchThread.run(Unknown Source)
Please help me how to solve this problem..

Er, sure. In the class pdfViewer.NewFileSegregater on line
1944 (!), in the valueChanged() method, something is pointing to
null.
That method is being called from
pdfViewer.NewFileSegregater.actionPerformed() on line
2918 (!!).
Of course, none of us know what's going on in those code
segements but you. And for the record, that's not how to spell
Segregator.

JList TransferHandler Drag and Drop -- w/Autoscroll?

Hi everyone,
Just wondering if anyone has written a TransferHandler for a JList that permits drag and drop reordering, that will also autoscroll its parent JScrollPane if dragging to a boundary? Don't want to reinvent the wheel!
Thanks.
Alex

Rolled my own, [can see it here|http://forums.crm.saeven.net/blog.php?b=2]
Hope it helps.

JList drag and drop to reorder items

I like to see a implementation of a JList supporting drag and drop to reorder items. The solution has to work with any object type in the datamodel.

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class ReorderList {
   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         @Override
         public void run() {
            new ReorderList().makeUI();
   public void makeUI() {
      Object[] data = {"One", "Two", "Three", "Four", "Five",
         "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve"
      DefaultListModel model = new DefaultListModel();
      for (Object object : data) {
         model.addElement(object);
      JList list = new JList(model);
      MouseAdapter listener = new ReorderListener(list);
      list.addMouseListener(listener);
      list.addMouseMotionListener(listener);
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(200, 200);
      frame.add(new JScrollPane(list));
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
class ReorderListener extends MouseAdapter {
   private JList list;
   private int pressIndex = 0;
   private int releaseIndex = 0;
   public ReorderListener(JList list) {
      if (!(list.getModel() instanceof DefaultListModel)) {
         throw new IllegalArgumentException("List must have a DefaultListModel");
      this.list = list;
   @Override
   public void mousePressed(MouseEvent e) {
      pressIndex = list.locationToIndex(e.getPoint());
   @Override
   public void mouseReleased(MouseEvent e) {
      releaseIndex = list.locationToIndex(e.getPoint());
      if (releaseIndex != pressIndex && releaseIndex != -1) {
         reorder();
   @Override
   public void mouseDragged(MouseEvent e) {
      mouseReleased(e);
      pressIndex = releaseIndex;
   private void reorder() {
      DefaultListModel model = (DefaultListModel) list.getModel();
      Object dragee = model.elementAt(pressIndex);
      model.removeElementAt(pressIndex);
      model.insertElementAt(dragee, releaseIndex);
}edit Reduced a few LoC
Edited by: Darryl.Burke

Drag and Drop an email from OutLook to JList.

Hi All,
Can anyone of you please guide me on how to implement drag and drop an email from microsoft outlook to JList.
Thanks in advance.!
Amit

It might just be Microsoft not using standards? I remember having a similar situation - I had an application that could have a zip entry fron 7-zip drag-and-dropped into it (came over as plain text, or maybe an InputStream, can't remember), but when you drill into a zip file with Windows (Vista at least), and try to drag-and-drop a zip entry from Windows Explorer, Java shows no dataflavors available. I just assumed Microsoft wasn't exporting the zip entry in any standard format (such as plain text).
Sorry, I know that wasn't very helpful, just thought I'd share a similar experience. :)

Drag and Drop to Change Order in a List

Does anyone know of an example where there is the ability to drag and drop elements in a list and thus change their order? (I.E. drag item one below item two and then item one and two change locations)
Thanks!

Check out http://java.sun.com/docs/books/tutorial/uiswing/misc/dnd.html
There's an example towards the end of the page for drag-and-drop between 2 JLists. Might be a good starting point.

Implementing drag and drop across components with drag image...

Hey all,
Finally got the hang of drag and drop. Not too hard, but a little time consuming. I found an article showing how to capture and drag a BufferedImage within a JTree. When you click and drag a node, it creates a BufferedImage of the node on screen and "ghosts" it a bit, which has a very appealing effect.
However, when I try to drag this image to a JList component, it disappears. So I created the same affect in the JList component. Now you can drag the image from the tree to the list and vice versa. However, the problem is, the image does not "fly over" the borders of the two components (butted up against each other) with the mouse. The image seems to go under the borders, while the mouse floats above everything.
What I would like to do is be able to drag the image all over the application, perhaps even the desktop in the case of a SDI application. I want to be able to see this image drag from my Java app over the Windows Explorer folder, just like how you can do that with Windows Explorer, dragging an image of the selected node into any app that supports the drop. I know we can handle the "transfer" data from explorer and vice versa, but how to be able to keep an image with the mouse?
My best guess is somehow using the Glass pane, grabbing a ref to its BufferedImage (if that is even what is there), and drawing the dragged item in that pane. But, then, how will the image move over the desktop outside of the app, where a glass pane is not?
Is there a way to draw on top of anything, anywhere, but still be able to redraw the background as the image moves with the mouse? There are times where the image may be big, so I don't want to have to capture the underlying screen as an image covering the size of the drag image to restore it as the drag image moves around.
Thank you.

We know cursors support some degree of transparence because they have shapes other than blocks.
I've done some playing around with
Toolkit.getDefaultToolkit().createCustomCursor(....);The sad news is, it seems that as soon as a pixel's alpha value is greater than 0, it automatically becomes 100% opaque.
The best you can do, is to take your image, and divide it into a pixel-checkerboard, and set the alpha value of alternating pixels to 0.
e.g.
BufferedImage i = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
        int[] data = ((DataBufferInt)i.getRaster().getDataBuffer()).getData();
        boolean on = true;
        for (int z=0; z<data.length; z++)
            if (on)
                data[z] = 0xffffffff;
            else
                data[z] = 0x00000000;
            on = !on;
            if (z%32==0) on = !on;
        Cursor hazyWhite = Toolkit.getDefaultToolkit().createCustomCursor(i, new Point(0,0), "hw");

Cannot drag and drop file from photos app to photoshop

Hi,
I'm trying to open a file saved in my Photos library in Photoshop. Previously in iPhoto I could drag and drop the file to open in other applications including Photoshop but this functionality appears to be missing in the new Photos app. Am i missing something? Or is there another way to do it?
thanks

Tristan,
I am stuck in the same place. Perhaps we could work on this together.
I am trying to drag a single item from a JList to a text editor, Word, etc. I have two problems:
1) I can't seem to get just the item in the JList to drag. It wants to drag the entire JList component.
2) How does one define the remote application as the drop target? Have not found any examples either.
Is the drop target actually the system clipboard?
Rp

Reorder items in JTree using drag-and-drop

Title says it all: before I start re-inventing the wheel, any code out there?
Think of the code that I need as an outliner.

Did you ever find a solution to this. I'm looking to implement a similar interface using a JList where the user can reorder drawing layers by dragging and dropping.
I'm temped to use a scrollpane and roll my own drag reorder code, so any supported behaviors would be welcome.
thanks,
Steven

Drag and Drop and java.io.NotSerializableException

I have been implementing some code to essentially allow me to drag and drop from one JTree to another. The requirement was to be able to drag multiple nodes at one time and drop them on the other JTree in the order selected.
I was getting a java.io.NotSerializableException when I was in the drop code in the destination jTree and could not figure out what was going on. Basically, I was wrapping all the objects that i wanted to transfer in a custom ArrayList subclass that implemented transferable. The NotSerializableException was was indicating that the object in the JList was not serializable.
If you are getting a NotSerializableException and you have defined a custom DataFlavor like so:
public static DataFlavor DATATYPE_TRANSFER =
        new DataFlavor(
           TransferableImplementor.class, // make sure that this is the class that implements transferable
            "Datatype Information");make sure that the .class is indeed the class that implements the transferable interface (and not some other random .class). You can be led down a wild goose chase on trying to make sure every object in your Transferable implementor class is serializable, when the problem lays in the DataFlavor instantiation.
Nik

If you haven't already read these, here are a couple of good sources for DND tree implementation details.
http://www.javaworld.com/javaworld/javatips/jw-javatip97.html
http://www.javaworld.com/javaworld/javatips/jw-javatip114.html

Drag and Drop and ListCellRenderer

Greetings,
I have some newbie questions about getting drag and drop working with ListCellRenderer. I'm using 1.4.2.
I have a JList using ListCellRenderer, and want to be able to copy the cells to native applications. (I don't care about dragging anything into my application.) And with drag and drop enabled, I can indeed copy the appropriate object from the list's Model. So far so good.
But what I'm copying is the result of the object's toString() method. I have some other data that I'd like to copy to, if the target can handle it. E.g., I have an image in the object; what do I have to do make that copyable if my target is something like the Gimp or MSPaint?
Another newbie question: how can I find out what kinds of DataFlavors native applications can handle?
Thanks,
P.

I have an answer to my first question: I never found a way to get at JList's built-in transfer handler to customize the data being transfered. If you don't like the cell object's default of toString() output, then you'll need to supply your own custom transfer handler. When I trap the mousedragged event, I get the corresponding cell information with getModel, and use that to pump the correct data into my transfer handler, and then call exportAsDrag as usual.

Drag and Drop(JList )

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