An event problem

Question

Imagine this scenario: A component with an added mouseMotionListener, the mouse is pressed upon the component, dragging occurs, the component is removed, invisible, but the mousebutton is still pressed, and I would like to keep getting mouseDragged events. Not peticularly from the original component, just from some component.
How do I do that?

Answer 1

If I understand well, you want to drag a component and this component become invisible when you start dragging and become visible when you drop it.
I realized something like this with drag and drop.
I created MoveableLabels which have a mouse listener and a mouse motion listener added to them. Those listeners transmit each event they receive to their parent container. This container have a drag gesture recognizer that catch the forwarded events and proceed with the dnd.
I did that because when the component become invisible, no more events are created, so it is necessary to transfer the event to the parent container which one stays visible.
Here the code :
The main class :
import java.awt.*;
import javax.swing.*;
public class TestDragComponent extends JFrame {
     public TestDragComponent() {
          super("Test");
          Container c = getContentPane();
          c.setLayout(new GridLayout(1,2));
          c.add(new MoveableComponentsContainer());
          c.add(new MoveableComponentsContainer());
          pack();
          setVisible(true);
     public static void main(String[] args) {
          new TestDragComponent();
}The class for moveable labels (you can do the same thing with all kinds of components :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class MoveableLabel extends JLabel {
     public MoveableLabel(String text) {
          super(text);
          MouseEventForwarder forwarder = new MouseEventForwarder();
          addMouseListener(forwarder);
          addMouseMotionListener(forwarder);
     final class MouseEventForwarder extends MouseInputAdapter {
          public void mousePressed(MouseEvent e) {
               Container parent = getParent();
               if (parent != null) {
                    Point newPoint = SwingUtilities.convertPoint(MoveableLabel.this, e.getPoint(), parent);
                    e.translatePoint(newPoint.x-e.getX(), newPoint.y-e.getY());
                    e.setSource(parent);
                    parent.dispatchEvent(e);
          public void mouseReleased(MouseEvent e) {
               Container parent = getParent();
               if (parent != null) {
                    Point newPoint = SwingUtilities.convertPoint(MoveableLabel.this, e.getPoint(), parent);
                    e.translatePoint(newPoint.x-e.getX(), newPoint.y-e.getY());
                    e.setSource(parent);
                    parent.dispatchEvent(e);               
          public void mouseDragged(MouseEvent e) {
               Container parent = getParent();
               if (parent != null) {
                    Point newPoint = SwingUtilities.convertPoint(MoveableLabel.this, e.getPoint(), parent);
                    e.translatePoint(newPoint.x-e.getX(), newPoint.y-e.getY());
                    e.setSource(parent);
                    parent.dispatchEvent(e);
}The class needed to transfer the comonents :
import java.awt.datatransfer.*;
import java.awt.*;
import java.util.*;
public class TransferableComponent implements Transferable {
     public static final DataFlavor COMPONENT_FLAVOR = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType, "Component");
     private Component component;
     private DataFlavor[] flavors = { COMPONENT_FLAVOR };
     * Constructs a transferrable component object for the specified component.
     public TransferableComponent(Component comp) {
          component = comp;
     public synchronized Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException {
          if (flavor == COMPONENT_FLAVOR) {
               return component;
          else {
               throw new UnsupportedFlavorException(flavor);     
     public DataFlavor[] getTransferDataFlavors() {
          return flavors;
     public boolean isDataFlavorSupported(DataFlavor flavor) {
          return Arrays.asList(flavors).contains(flavor);
}And the last class : the container which manages dnd :
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
public class MoveableComponentsContainer extends JPanel {     
     public DragSource dragSource;
     public DropTarget dropTarget;
     public MoveableComponentsContainer() {
          setBorder(BorderFactory.createBevelBorder(BevelBorder.LOWERED, Color.white, Color.gray));
          setLayout(new FlowLayout(FlowLayout.LEFT,5,5));          
          dragSource = new DragSource();
          ComponentDragSourceListener tdsl = new ComponentDragSourceListener();
          dragSource.createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, new ComponentDragGestureListener(tdsl));
          ComponentDropTargetListener tdtl = new ComponentDropTargetListener();
          dropTarget = new DropTarget(this, DnDConstants.ACTION_MOVE, tdtl);
          setPreferredSize(new Dimension(400,400));
          addMoveableComponents();
     private void addMoveableComponents() {
          add(new MoveableLabel("label 1"));
          add(new MoveableLabel("label 2"));
          add(new MoveableLabel("label 3"));
          add(new MoveableLabel("label 4"));
     final class ComponentDragSourceListener implements DragSourceListener {
          public void dragDropEnd(DragSourceDropEvent dsde) {
          public void dragEnter(DragSourceDragEvent dsde)  {
               int action = dsde.getDropAction();
               if (action == DnDConstants.ACTION_MOVE) {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
               else {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
          public void dragOver(DragSourceDragEvent dsde) {
               int action = dsde.getDropAction();
               if (action == DnDConstants.ACTION_MOVE) {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
               else {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
          public void dropActionChanged(DragSourceDragEvent dsde)  {
               int action = dsde.getDropAction();
               if (action == DnDConstants.ACTION_MOVE) {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop);
               else {
                    dsde.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
          public void dragExit(DragSourceEvent dse) {
             dse.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop);
     final class ComponentDragGestureListener implements DragGestureListener {
          ComponentDragSourceListener tdsl;
          public ComponentDragGestureListener(ComponentDragSourceListener tdsl) {
               this.tdsl = tdsl;
          public void dragGestureRecognized(DragGestureEvent dge) {
               Component comp = getComponentAt(dge.getDragOrigin());
               if (comp != null && comp != MoveableComponentsContainer.this) {
                    remove(comp);
                    dragSource.startDrag(dge, DragSource.DefaultMoveDrop , new TransferableComponent(comp), tdsl);     
                    revalidate();
                    repaint();
     final class ComponentDropTargetListener implements DropTargetListener {
          private Rectangle rect2D = new Rectangle();
          Insets insets;
          public void dragEnter(DropTargetDragEvent dtde) {
               dtde.acceptDrag(dtde.getDropAction());
          public void dragExit(DropTargetEvent dte) {
          public void dragOver(DropTargetDragEvent dtde) {
               dtde.acceptDrag(dtde.getDropAction());
          public void dropActionChanged(DropTargetDragEvent dtde) {
               dtde.acceptDrag(dtde.getDropAction());
          public void drop(DropTargetDropEvent dtde) {
               try {
                    int action = dtde.getDropAction();
                    Transferable transferable = dtde.getTransferable();
                    if (transferable.isDataFlavorSupported(TransferableComponent.COMPONENT_FLAVOR)) {
                         Component comp = (Component) transferable.getTransferData(TransferableComponent.COMPONENT_FLAVOR);
                         Point location = dtde.getLocation();
                         if (comp == null) {
                              dtde.rejectDrop();
                              dtde.dropComplete(false);
                              revalidate();
                              repaint();
                              return;                              
                         else {                         
                              int index = getComponentIndex(getComponentAt(location));
                              add(comp, index);
                              dtde.dropComplete(true);
                              revalidate();
                              repaint();
                              return;
                    else {
                         dtde.rejectDrop();
                         dtde.dropComplete(false);
                         return;               
               catch (Exception e) {     
                    System.out.println(e);
                    dtde.rejectDrop();
                    dtde.dropComplete(false);
     public int getComponentIndex(Component c) {
          Component[] comps = getComponents();
          for (int i = 0; i<comps.length; i++) {     
               if (comps[i] == c) {
                    return(i);
          return(-1);
}In this application there are two panels (left and right) containing each four moveable labels.
You can move the labels inside a same panel and from a panel to the other. The layout manager of the panels is a flow layout.
For example : if you press the mouse button over a label and start a drag, the label will become invisible. If you drag the mouse (mouse button always pressed) over another label, the dragged label will become visible and will be inserted before or after the other label (depending on the mouse position).
I hope you will find ideas with this help,
Denis