¿Cómo implementar la pestaña arrastrable usando Java Swing?

¿Cómo implemento una pestaña arrastrable usando Java Swing? En lugar del JTabbedPane estático, me gustaría arrastrar y soltar una pestaña en una posición diferente para reorganizar las tabs.

EDIT : los tutoriales de Java: arrastrar y soltar y transferencia de datos .

Maldiciones! Golpeado al golpe por una búsqueda en Google. Desafortunadamente, es cierto que no hay una manera fácil de crear paneles de tabs que se puedan arrastrar (o cualquier otro componente) en Swing. Entonces, mientras el ejemplo anterior está completo, este que acabo de escribir es un poco más simple. Por lo tanto, se espera que demuestre que las técnicas más avanzadas están un poco más claras. Los pasos son:

  1. Detecta que ha ocurrido un arrastre
  2. Dibujar la pestaña arrastrada a un buffer fuera de pantalla
  3. Siga la posición del mouse mientras se produce el arrastre
  4. Dibuja la pestaña en el buffer en la parte superior del componente.

El ejemplo anterior le dará lo que desea, pero si realmente quiere comprender las técnicas aplicadas aquí, podría ser un mejor ejercicio redondear los bordes de este ejemplo y agregar las características adicionales que se muestran arriba.

O tal vez estoy decepcionado porque pasé un tiempo escribiendo esta solución cuando ya existía uno: p

import java.awt.Component; import java.awt.Graphics; import java.awt.Image; import java.awt.Point; import java.awt.Rectangle; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseMotionAdapter; import java.awt.image.BufferedImage; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JTabbedPane; public class DraggableTabbedPane extends JTabbedPane { private boolean dragging = false; private Image tabImage = null; private Point currentMouseLocation = null; private int draggedTabIndex = 0; public DraggableTabbedPane() { super(); addMouseMotionListener(new MouseMotionAdapter() { public void mouseDragged(MouseEvent e) { if(!dragging) { // Gets the tab index based on the mouse position int tabNumber = getUI().tabForCoordinate(DraggableTabbedPane.this, e.getX(), e.getY()); if(tabNumber >= 0) { draggedTabIndex = tabNumber; Rectangle bounds = getUI().getTabBounds(DraggableTabbedPane.this, tabNumber); // Paint the tabbed pane to a buffer Image totalImage = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_ARGB); Graphics totalGraphics = totalImage.getGraphics(); totalGraphics.setClip(bounds); // Don't be double buffered when painting to a static image. setDoubleBuffered(false); paintComponent(totalGraphics); // Paint just the dragged tab to the buffer tabImage = new BufferedImage(bounds.width, bounds.height, BufferedImage.TYPE_INT_ARGB); Graphics graphics = tabImage.getGraphics(); graphics.drawImage(totalImage, 0, 0, bounds.width, bounds.height, bounds.x, bounds.y, bounds.x + bounds.width, bounds.y+bounds.height, DraggableTabbedPane.this); dragging = true; repaint(); } } else { currentMouseLocation = e.getPoint(); // Need to repaint repaint(); } super.mouseDragged(e); } }); addMouseListener(new MouseAdapter() { public void mouseReleased(MouseEvent e) { if(dragging) { int tabNumber = getUI().tabForCoordinate(DraggableTabbedPane.this, e.getX(), 10); if(tabNumber >= 0) { Component comp = getComponentAt(draggedTabIndex); String title = getTitleAt(draggedTabIndex); removeTabAt(draggedTabIndex); insertTab(title, null, comp, null, tabNumber); } } dragging = false; tabImage = null; } }); } protected void paintComponent(Graphics g) { super.paintComponent(g); // Are we dragging? if(dragging && currentMouseLocation != null && tabImage != null) { // Draw the dragged tab g.drawImage(tabImage, currentMouseLocation.x, currentMouseLocation.y, this); } } public static void main(String[] args) { JFrame test = new JFrame("Tab test"); test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); test.setSize(400, 400); DraggableTabbedPane tabs = new DraggableTabbedPane(); tabs.addTab("One", new JButton("One")); tabs.addTab("Two", new JButton("Two")); tabs.addTab("Three", new JButton("Three")); tabs.addTab("Four", new JButton("Four")); test.add(tabs); test.setVisible(true); } } 

Me gustó el DnDTabbedPane de Terai Atsuhiro san , pero quería más de él. La implementación original de Terai transfirió tabs dentro de TabbedPane, pero sería mejor si pudiera arrastrar desde un Panel de tabs a otro.

Inspirado por el esfuerzo de @Tom, decidí modificar el código yo mismo. Hay algunos detalles que agregué. Por ejemplo, la pestaña fantasma ahora se desliza a lo largo del panel con tabs en lugar de moverse junto con el mouse.

setAcceptor(TabAcceptor a_acceptor) debe dejar que el código del consumidor decida si se permite que una pestaña se transfiera de un panel con tabs a otro. El aceptador predeterminado siempre devuelve true .

 /** Modified DnDTabbedPane.java * http://java-swing-tips.blogspot.com/2008/04/drag-and-drop-tabs-in-jtabbedpane.html * originally written by Terai Atsuhiro. * so that tabs can be transfered from one pane to another. * eed3si9n. */ import java.awt.*; import java.awt.datatransfer.*; import java.awt.dnd.*; import java.awt.geom.*; import java.awt.image.*; import javax.swing.*; public class DnDTabbedPane extends JTabbedPane { public static final long serialVersionUID = 1L; private static final int LINEWIDTH = 3; private static final String NAME = "TabTransferData"; private final DataFlavor FLAVOR = new DataFlavor( DataFlavor.javaJVMLocalObjectMimeType, NAME); private static GhostGlassPane s_glassPane = new GhostGlassPane(); private boolean m_isDrawRect = false; private final Rectangle2D m_lineRect = new Rectangle2D.Double(); private final Color m_lineColor = new Color(0, 100, 255); private TabAcceptor m_acceptor = null; public DnDTabbedPane() { super(); final DragSourceListener dsl = new DragSourceListener() { public void dragEnter(DragSourceDragEvent e) { e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop); } public void dragExit(DragSourceEvent e) { e.getDragSourceContext() .setCursor(DragSource.DefaultMoveNoDrop); m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; s_glassPane.setPoint(new Point(-1000, -1000)); s_glassPane.repaint(); } public void dragOver(DragSourceDragEvent e) { //e.getLocation() //This method returns a Point indicating the cursor location in screen coordinates at the moment TabTransferData data = getTabTransferData(e); if (data == null) { e.getDragSourceContext().setCursor( DragSource.DefaultMoveNoDrop); return; } // if /* Point tabPt = e.getLocation(); SwingUtilities.convertPointFromScreen(tabPt, DnDTabbedPane.this); if (DnDTabbedPane.this.contains(tabPt)) { int targetIdx = getTargetTabIndex(tabPt); int sourceIndex = data.getTabIndex(); if (getTabAreaBound().contains(tabPt) && (targetIdx >= 0) && (targetIdx != sourceIndex) && (targetIdx != sourceIndex + 1)) { e.getDragSourceContext().setCursor( DragSource.DefaultMoveDrop); return; } // if e.getDragSourceContext().setCursor( DragSource.DefaultMoveNoDrop); return; } // if */ e.getDragSourceContext().setCursor( DragSource.DefaultMoveDrop); } public void dragDropEnd(DragSourceDropEvent e) { m_isDrawRect = false; m_lineRect.setRect(0, 0, 0, 0); // m_dragTabIndex = -1; if (hasGhost()) { s_glassPane.setVisible(false); s_glassPane.setImage(null); } } public void dropActionChanged(DragSourceDragEvent e) { } }; final DragGestureListener dgl = new DragGestureListener() { public void dragGestureRecognized(DragGestureEvent e) { // System.out.println("dragGestureRecognized"); Point tabPt = e.getDragOrigin(); int dragTabIndex = indexAtLocation(tabPt.x, tabPt.y); if (dragTabIndex < 0) { return; } // if initGlassPane(e.getComponent(), e.getDragOrigin(), dragTabIndex); try { e.startDrag(DragSource.DefaultMoveDrop, new TabTransferable(DnDTabbedPane.this, dragTabIndex), dsl); } catch (InvalidDnDOperationException idoe) { idoe.printStackTrace(); } } }; //dropTarget = new DropTarget(this, DnDConstants.ACTION_COPY_OR_MOVE, new CDropTargetListener(), true); new DragSource().createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, dgl); m_acceptor = new TabAcceptor() { public boolean isDropAcceptable(DnDTabbedPane a_component, int a_index) { return true; } }; } public TabAcceptor getAcceptor() { return m_acceptor; } public void setAcceptor(TabAcceptor a_value) { m_acceptor = a_value; } private TabTransferData getTabTransferData(DropTargetDropEvent a_event) { try { TabTransferData data = (TabTransferData) a_event.getTransferable().getTransferData(FLAVOR); return data; } catch (Exception e) { e.printStackTrace(); } return null; } private TabTransferData getTabTransferData(DropTargetDragEvent a_event) { try { TabTransferData data = (TabTransferData) a_event.getTransferable().getTransferData(FLAVOR); return data; } catch (Exception e) { e.printStackTrace(); } return null; } private TabTransferData getTabTransferData(DragSourceDragEvent a_event) { try { TabTransferData data = (TabTransferData) a_event.getDragSourceContext() .getTransferable().getTransferData(FLAVOR); return data; } catch (Exception e) { e.printStackTrace(); } return null; } class TabTransferable implements Transferable { private TabTransferData m_data = null; public TabTransferable(DnDTabbedPane a_tabbedPane, int a_tabIndex) { m_data = new TabTransferData(DnDTabbedPane.this, a_tabIndex); } public Object getTransferData(DataFlavor flavor) { return m_data; // return DnDTabbedPane.this; } public DataFlavor[] getTransferDataFlavors() { DataFlavor[] f = new DataFlavor[1]; f[0] = FLAVOR; return f; } public boolean isDataFlavorSupported(DataFlavor flavor) { return flavor.getHumanPresentableName().equals(NAME); } } class TabTransferData { private DnDTabbedPane m_tabbedPane = null; private int m_tabIndex = -1; public TabTransferData() { } public TabTransferData(DnDTabbedPane a_tabbedPane, int a_tabIndex) { m_tabbedPane = a_tabbedPane; m_tabIndex = a_tabIndex; } public DnDTabbedPane getTabbedPane() { return m_tabbedPane; } public void setTabbedPane(DnDTabbedPane pane) { m_tabbedPane = pane; } public int getTabIndex() { return m_tabIndex; } public void setTabIndex(int index) { m_tabIndex = index; } } private Point buildGhostLocation(Point a_location) { Point retval = new Point(a_location); switch (getTabPlacement()) { case JTabbedPane.TOP: { retval.y = 1; retval.x -= s_glassPane.getGhostWidth() / 2; } break; case JTabbedPane.BOTTOM: { retval.y = getHeight() - 1 - s_glassPane.getGhostHeight(); retval.x -= s_glassPane.getGhostWidth() / 2; } break; case JTabbedPane.LEFT: { retval.x = 1; retval.y -= s_glassPane.getGhostHeight() / 2; } break; case JTabbedPane.RIGHT: { retval.x = getWidth() - 1 - s_glassPane.getGhostWidth(); retval.y -= s_glassPane.getGhostHeight() / 2; } break; } // switch retval = SwingUtilities.convertPoint(DnDTabbedPane.this, retval, s_glassPane); return retval; } class CDropTargetListener implements DropTargetListener { public void dragEnter(DropTargetDragEvent e) { // System.out.println("DropTarget.dragEnter: " + DnDTabbedPane.this); if (isDragAcceptable(e)) { e.acceptDrag(e.getDropAction()); } else { e.rejectDrag(); } // if } public void dragExit(DropTargetEvent e) { // System.out.println("DropTarget.dragExit: " + DnDTabbedPane.this); m_isDrawRect = false; } public void dropActionChanged(DropTargetDragEvent e) { } public void dragOver(final DropTargetDragEvent e) { TabTransferData data = getTabTransferData(e); if (getTabPlacement() == JTabbedPane.TOP || getTabPlacement() == JTabbedPane.BOTTOM) { initTargetLeftRightLine(getTargetTabIndex(e.getLocation()), data); } else { initTargetTopBottomLine(getTargetTabIndex(e.getLocation()), data); } // if-else repaint(); if (hasGhost()) { s_glassPane.setPoint(buildGhostLocation(e.getLocation())); s_glassPane.repaint(); } } public void drop(DropTargetDropEvent a_event) { // System.out.println("DropTarget.drop: " + DnDTabbedPane.this); if (isDropAcceptable(a_event)) { convertTab(getTabTransferData(a_event), getTargetTabIndex(a_event.getLocation())); a_event.dropComplete(true); } else { a_event.dropComplete(false); } // if-else m_isDrawRect = false; repaint(); } public boolean isDragAcceptable(DropTargetDragEvent e) { Transferable t = e.getTransferable(); if (t == null) { return false; } // if DataFlavor[] flavor = e.getCurrentDataFlavors(); if (!t.isDataFlavorSupported(flavor[0])) { return false; } // if TabTransferData data = getTabTransferData(e); if (DnDTabbedPane.this == data.getTabbedPane() && data.getTabIndex() >= 0) { return true; } // if if (DnDTabbedPane.this != data.getTabbedPane()) { if (m_acceptor != null) { return m_acceptor.isDropAcceptable(data.getTabbedPane(), data.getTabIndex()); } // if } // if return false; } public boolean isDropAcceptable(DropTargetDropEvent e) { Transferable t = e.getTransferable(); if (t == null) { return false; } // if DataFlavor[] flavor = e.getCurrentDataFlavors(); if (!t.isDataFlavorSupported(flavor[0])) { return false; } // if TabTransferData data = getTabTransferData(e); if (DnDTabbedPane.this == data.getTabbedPane() && data.getTabIndex() >= 0) { return true; } // if if (DnDTabbedPane.this != data.getTabbedPane()) { if (m_acceptor != null) { return m_acceptor.isDropAcceptable(data.getTabbedPane(), data.getTabIndex()); } // if } // if return false; } } private boolean m_hasGhost = true; public void setPaintGhost(boolean flag) { m_hasGhost = flag; } public boolean hasGhost() { return m_hasGhost; } /** * returns potential index for drop. * @param a_point point given in the drop site component's coordinate * @return returns potential index for drop. */ private int getTargetTabIndex(Point a_point) { boolean isTopOrBottom = getTabPlacement() == JTabbedPane.TOP || getTabPlacement() == JTabbedPane.BOTTOM; // if the pane is empty, the target index is always zero. if (getTabCount() == 0) { return 0; } // if for (int i = 0; i < getTabCount(); i++) { Rectangle r = getBoundsAt(i); if (isTopOrBottom) { r.setRect(rx - r.width / 2, ry, r.width, r.height); } else { r.setRect(rx, ry - r.height / 2, r.width, r.height); } // if-else if (r.contains(a_point)) { return i; } // if } // for Rectangle r = getBoundsAt(getTabCount() - 1); if (isTopOrBottom) { int x = rx + r.width / 2; r.setRect(x, ry, getWidth() - x, r.height); } else { int y = ry + r.height / 2; r.setRect(rx, y, r.width, getHeight() - y); } // if-else return r.contains(a_point) ? getTabCount() : -1; } private void convertTab(TabTransferData a_data, int a_targetIndex) { DnDTabbedPane source = a_data.getTabbedPane(); int sourceIndex = a_data.getTabIndex(); if (sourceIndex < 0) { return; } // if Component cmp = source.getComponentAt(sourceIndex); String str = source.getTitleAt(sourceIndex); if (this != source) { source.remove(sourceIndex); if (a_targetIndex == getTabCount()) { addTab(str, cmp); } else { if (a_targetIndex < 0) { a_targetIndex = 0; } // if insertTab(str, null, cmp, null, a_targetIndex); } // if setSelectedComponent(cmp); // System.out.println("press="+sourceIndex+" next="+a_targetIndex); return; } // if if (a_targetIndex < 0 || sourceIndex == a_targetIndex) { //System.out.println("press="+prev+" next="+next); return; } // if if (a_targetIndex == getTabCount()) { //System.out.println("last: press="+prev+" next="+next); source.remove(sourceIndex); addTab(str, cmp); setSelectedIndex(getTabCount() - 1); } else if (sourceIndex > a_targetIndex) { //System.out.println(" >: press="+prev+" next="+next); source.remove(sourceIndex); insertTab(str, null, cmp, null, a_targetIndex); setSelectedIndex(a_targetIndex); } else { //System.out.println(" <: press="+prev+" next="+next); source.remove(sourceIndex); insertTab(str, null, cmp, null, a_targetIndex - 1); setSelectedIndex(a_targetIndex - 1); } } private void initTargetLeftRightLine(int next, TabTransferData a_data) { if (next < 0) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; return; } // if if ((a_data.getTabbedPane() == this) && (a_data.getTabIndex() == next || next - a_data.getTabIndex() == 1)) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; } else if (getTabCount() == 0) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; return; } else if (next == 0) { Rectangle rect = getBoundsAt(0); m_lineRect.setRect(-LINEWIDTH / 2, rect.y, LINEWIDTH, rect.height); m_isDrawRect = true; } else if (next == getTabCount()) { Rectangle rect = getBoundsAt(getTabCount() - 1); m_lineRect.setRect(rect.x + rect.width - LINEWIDTH / 2, rect.y, LINEWIDTH, rect.height); m_isDrawRect = true; } else { Rectangle rect = getBoundsAt(next - 1); m_lineRect.setRect(rect.x + rect.width - LINEWIDTH / 2, rect.y, LINEWIDTH, rect.height); m_isDrawRect = true; } } private void initTargetTopBottomLine(int next, TabTransferData a_data) { if (next < 0) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; return; } // if if ((a_data.getTabbedPane() == this) && (a_data.getTabIndex() == next || next - a_data.getTabIndex() == 1)) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; } else if (getTabCount() == 0) { m_lineRect.setRect(0, 0, 0, 0); m_isDrawRect = false; return; } else if (next == getTabCount()) { Rectangle rect = getBoundsAt(getTabCount() - 1); m_lineRect.setRect(rect.x, rect.y + rect.height - LINEWIDTH / 2, rect.width, LINEWIDTH); m_isDrawRect = true; } else if (next == 0) { Rectangle rect = getBoundsAt(0); m_lineRect.setRect(rect.x, -LINEWIDTH / 2, rect.width, LINEWIDTH); m_isDrawRect = true; } else { Rectangle rect = getBoundsAt(next - 1); m_lineRect.setRect(rect.x, rect.y + rect.height - LINEWIDTH / 2, rect.width, LINEWIDTH); m_isDrawRect = true; } } private void initGlassPane(Component c, Point tabPt, int a_tabIndex) { //Point p = (Point) pt.clone(); getRootPane().setGlassPane(s_glassPane); if (hasGhost()) { Rectangle rect = getBoundsAt(a_tabIndex); BufferedImage image = new BufferedImage(c.getWidth(), c.getHeight(), BufferedImage.TYPE_INT_ARGB); Graphics g = image.getGraphics(); c.paint(g); image = image.getSubimage(rect.x, rect.y, rect.width, rect.height); s_glassPane.setImage(image); } // if s_glassPane.setPoint(buildGhostLocation(tabPt)); s_glassPane.setVisible(true); } private Rectangle getTabAreaBound() { Rectangle lastTab = getUI().getTabBounds(this, getTabCount() - 1); return new Rectangle(0, 0, getWidth(), lastTab.y + lastTab.height); } public void paintComponent(Graphics g) { super.paintComponent(g); if (m_isDrawRect) { Graphics2D g2 = (Graphics2D) g; g2.setPaint(m_lineColor); g2.fill(m_lineRect); } // if } public interface TabAcceptor { boolean isDropAcceptable(DnDTabbedPane a_component, int a_index); } } class GhostGlassPane extends JPanel { public static final long serialVersionUID = 1L; private final AlphaComposite m_composite; private Point m_location = new Point(0, 0); private BufferedImage m_draggingGhost = null; public GhostGlassPane() { setOpaque(false); m_composite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.7f); } public void setImage(BufferedImage draggingGhost) { m_draggingGhost = draggingGhost; } public void setPoint(Point a_location) { m_location.x = a_location.x; m_location.y = a_location.y; } public int getGhostWidth() { if (m_draggingGhost == null) { return 0; } // if return m_draggingGhost.getWidth(this); } public int getGhostHeight() { if (m_draggingGhost == null) { return 0; } // if return m_draggingGhost.getHeight(this); } public void paintComponent(Graphics g) { if (m_draggingGhost == null) { return; } // if Graphics2D g2 = (Graphics2D) g; g2.setComposite(m_composite); g2.drawImage(m_draggingGhost, (int) m_location.getX(), (int) m_location.getY(), null); } } 

Encontré este código en los tubos :

 class DnDTabbedPane extends JTabbedPane { private static final int LINEWIDTH = 3; private static final String NAME = "test"; private final GhostGlassPane glassPane = new GhostGlassPane(); private final Rectangle2D lineRect = new Rectangle2D.Double(); private final Color lineColor = new Color(0, 100, 255); //private final DragSource dragSource = new DragSource(); //private final DropTarget dropTarget; private int dragTabIndex = -1; public DnDTabbedPane() { super(); final DragSourceListener dsl = new DragSourceListener() { public void dragEnter(DragSourceDragEvent e) { e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop); } public void dragExit(DragSourceEvent e) { e.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop); lineRect.setRect(0,0,0,0); glassPane.setPoint(new Point(-1000,-1000)); glassPane.repaint(); } public void dragOver(DragSourceDragEvent e) { //e.getLocation() //This method returns a Point indicating the cursor location in screen coordinates at the moment Point tabPt = e.getLocation(); SwingUtilities.convertPointFromScreen(tabPt, DnDTabbedPane.this); Point glassPt = e.getLocation(); SwingUtilities.convertPointFromScreen(glassPt, glassPane); int targetIdx = getTargetTabIndex(glassPt); if(getTabAreaBound().contains(tabPt) && targetIdx>=0 && targetIdx!=dragTabIndex && targetIdx!=dragTabIndex+1) { e.getDragSourceContext().setCursor(DragSource.DefaultMoveDrop); }else{ e.getDragSourceContext().setCursor(DragSource.DefaultMoveNoDrop); } } public void dragDropEnd(DragSourceDropEvent e) { lineRect.setRect(0,0,0,0); dragTabIndex = -1; if(hasGhost()) { glassPane.setVisible(false); glassPane.setImage(null); } } public void dropActionChanged(DragSourceDragEvent e) {} }; final Transferable t = new Transferable() { private final DataFlavor FLAVOR = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType, NAME); public Object getTransferData(DataFlavor flavor) { return DnDTabbedPane.this; } public DataFlavor[] getTransferDataFlavors() { DataFlavor[] f = new DataFlavor[1]; f[0] = this.FLAVOR; return f; } public boolean isDataFlavorSupported(DataFlavor flavor) { return flavor.getHumanPresentableName().equals(NAME); } }; final DragGestureListener dgl = new DragGestureListener() { public void dragGestureRecognized(DragGestureEvent e) { Point tabPt = e.getDragOrigin(); dragTabIndex = indexAtLocation(tabPt.x, tabPt.y); if(dragTabIndex<0) return; initGlassPane(e.getComponent(), e.getDragOrigin()); try{ e.startDrag(DragSource.DefaultMoveDrop, t, dsl); }catch(InvalidDnDOperationException idoe) { idoe.printStackTrace(); } } }; //dropTarget = new DropTarget(glassPane, DnDConstants.ACTION_COPY_OR_MOVE, new CDropTargetListener(), true); new DragSource().createDefaultDragGestureRecognizer(this, DnDConstants.ACTION_COPY_OR_MOVE, dgl); } class CDropTargetListener implements DropTargetListener{ public void dragEnter(DropTargetDragEvent e) { if(isDragAcceptable(e)) e.acceptDrag(e.getDropAction()); else e.rejectDrag(); } public void dragExit(DropTargetEvent e) {} public void dropActionChanged(DropTargetDragEvent e) {} public void dragOver(final DropTargetDragEvent e) { if(getTabPlacement()==JTabbedPane.TOP || getTabPlacement()==JTabbedPane.BOTTOM) { initTargetLeftRightLine(getTargetTabIndex(e.getLocation())); }else{ initTargetTopBottomLine(getTargetTabIndex(e.getLocation())); } repaint(); if(hasGhost()) { glassPane.setPoint(e.getLocation()); glassPane.repaint(); } } public void drop(DropTargetDropEvent e) { if(isDropAcceptable(e)) { convertTab(dragTabIndex, getTargetTabIndex(e.getLocation())); e.dropComplete(true); }else{ e.dropComplete(false); } repaint(); } public boolean isDragAcceptable(DropTargetDragEvent e) { Transferable t = e.getTransferable(); if(t==null) return false; DataFlavor[] f = e.getCurrentDataFlavors(); if(t.isDataFlavorSupported(f[0]) && dragTabIndex>=0) { return true; } return false; } public boolean isDropAcceptable(DropTargetDropEvent e) { Transferable t = e.getTransferable(); if(t==null) return false; DataFlavor[] f = t.getTransferDataFlavors(); if(t.isDataFlavorSupported(f[0]) && dragTabIndex>=0) { return true; } return false; } } private boolean hasGhost = true; public void setPaintGhost(boolean flag) { hasGhost = flag; } public boolean hasGhost() { return hasGhost; } private int getTargetTabIndex(Point glassPt) { Point tabPt = SwingUtilities.convertPoint(glassPane, glassPt, DnDTabbedPane.this); boolean isTB = getTabPlacement()==JTabbedPane.TOP || getTabPlacement()==JTabbedPane.BOTTOM; for(int i=0;i: press="+prev+" next="+next); remove(prev); insertTab(str, null, cmp, null, next); setSelectedIndex(next); }else{ //System.out.println(" <: press="+prev+" next="+next); remove(prev); insertTab(str, null, cmp, null, next-1); setSelectedIndex(next-1); } } private void initTargetLeftRightLine(int next) { if(next<0 || dragTabIndex==next || next-dragTabIndex==1) { lineRect.setRect(0,0,0,0); }else if(next==getTabCount()) { Rectangle rect = getBoundsAt(getTabCount()-1); lineRect.setRect(rect.x+rect.width-LINEWIDTH/2,rect.y,LINEWIDTH,rect.height); }else if(next==0) { Rectangle rect = getBoundsAt(0); lineRect.setRect(-LINEWIDTH/2,rect.y,LINEWIDTH,rect.height); }else{ Rectangle rect = getBoundsAt(next-1); lineRect.setRect(rect.x+rect.width-LINEWIDTH/2,rect.y,LINEWIDTH,rect.height); } } private void initTargetTopBottomLine(int next) { if(next<0 || dragTabIndex==next || next-dragTabIndex==1) { lineRect.setRect(0,0,0,0); }else if(next==getTabCount()) { Rectangle rect = getBoundsAt(getTabCount()-1); lineRect.setRect(rect.x,rect.y+rect.height-LINEWIDTH/2,rect.width,LINEWIDTH); }else if(next==0) { Rectangle rect = getBoundsAt(0); lineRect.setRect(rect.x,-LINEWIDTH/2,rect.width,LINEWIDTH); }else{ Rectangle rect = getBoundsAt(next-1); lineRect.setRect(rect.x,rect.y+rect.height-LINEWIDTH/2,rect.width,LINEWIDTH); } } private void initGlassPane(Component c, Point tabPt) { //Point p = (Point) pt.clone(); getRootPane().setGlassPane(glassPane); if(hasGhost()) { Rectangle rect = getBoundsAt(dragTabIndex); BufferedImage image = new BufferedImage(c.getWidth(), c.getHeight(), BufferedImage.TYPE_INT_ARGB); Graphics g = image.getGraphics(); c.paint(g); image = image.getSubimage(rect.x,rect.y,rect.width,rect.height); glassPane.setImage(image); } Point glassPt = SwingUtilities.convertPoint(c, tabPt, glassPane); glassPane.setPoint(glassPt); glassPane.setVisible(true); } private Rectangle getTabAreaBound() { Rectangle lastTab = getUI().getTabBounds(this, getTabCount()-1); return new Rectangle(0,0,getWidth(),lastTab.y+lastTab.height); } public void paintComponent(Graphics g) { super.paintComponent(g); if(dragTabIndex>=0) { Graphics2D g2 = (Graphics2D)g; g2.setPaint(lineColor); g2.fill(lineRect); } } } class GhostGlassPane extends JPanel { private final AlphaComposite composite; private Point location = new Point(0, 0); private BufferedImage draggingGhost = null; public GhostGlassPane() { setOpaque(false); composite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f); } public void setImage(BufferedImage draggingGhost) { this.draggingGhost = draggingGhost; } public void setPoint(Point location) { this.location = location; } public void paintComponent(Graphics g) { if(draggingGhost == null) return; Graphics2D g2 = (Graphics2D) g; g2.setComposite(composite); double xx = location.getX() - (draggingGhost.getWidth(this) /2d); double yy = location.getY() - (draggingGhost.getHeight(this)/2d); g2.drawImage(draggingGhost, (int)xx, (int)yy , null); } } 

@ Tony: Parece que la solución de Euguenes pasa por alto la preservación de TabComponents durante un intercambio.

El método convertTab solo necesita recordar el TabComponent y establecerlo en las nuevas tabs que crea.

Intenta usar esto:

  private void convertTab(TabTransferData a_data, int a_targetIndex) { DnDTabbedPane source = a_data.getTabbedPane(); System.out.println("this=source? " + (this == source)); int sourceIndex = a_data.getTabIndex(); if (sourceIndex < 0) { return; } // if //Save the tab's component, title, and TabComponent. Component cmp = source.getComponentAt(sourceIndex); String str = source.getTitleAt(sourceIndex); Component tcmp = source.getTabComponentAt(sourceIndex); if (this != source) { source.remove(sourceIndex); if (a_targetIndex == getTabCount()) { addTab(str, cmp); setTabComponentAt(getTabCount()-1, tcmp); } else { if (a_targetIndex < 0) { a_targetIndex = 0; } // if insertTab(str, null, cmp, null, a_targetIndex); setTabComponentAt(a_targetIndex, tcmp); } // if setSelectedComponent(cmp); return; } // if if (a_targetIndex < 0 || sourceIndex == a_targetIndex) { return; } // if if (a_targetIndex == getTabCount()) { source.remove(sourceIndex); addTab(str, cmp); setTabComponentAt(getTabCount() - 1, tcmp); setSelectedIndex(getTabCount() - 1); } else if (sourceIndex > a_targetIndex) { source.remove(sourceIndex); insertTab(str, null, cmp, null, a_targetIndex); setTabComponentAt(a_targetIndex, tcmp); setSelectedIndex(a_targetIndex); } else { source.remove(sourceIndex); insertTab(str, null, cmp, null, a_targetIndex - 1); setTabComponentAt(a_targetIndex - 1, tcmp); setSelectedIndex(a_targetIndex - 1); } } 

Agregue esto a isDragAcceptable para evitar excepciones:

 boolean transferDataFlavorFound = false; for (DataFlavor transferDataFlavor : t.getTransferDataFlavors()) { if (FLAVOR.equals(transferDataFlavor)) { transferDataFlavorFound = true; break; } } if (transferDataFlavorFound == false) { return false; }