使用拖放对列表框进行重新排序，拖放列表框排序,使用拖放对列表框进行重新

使用拖放对列表框进行重新排序，拖放列表框排序,使用拖放对列表框进行重新

使用拖放对列表框进行重新排序

使用拖放对列表框进行重新排序

public class ReorderableJList extends JList     implements DragSourceListener, DropTargetListener, DragGestureListener {    static DataFlavor localObjectFlavor;    static {        try {            localObjectFlavor =                new DataFlavor (DataFlavor.javaJVMLocalObjectMimeType);        } catch (ClassNotFoundException cnfe) { cnfe.printStackTrace(); }     }     static DataFlavor[] supportedFlavors = { localObjectFlavor };     DragSource dragSource;     DropTarget dropTarget;     Object dropTargetCell;     int draggedIndex = -1;    public ReorderableJList () {        super();        setCellRenderer (new ReorderableListCellRenderer());        setModel (new DefaultListModel());        dragSource = new DragSource();        DragGestureRecognizer dgr =            dragSource.createDefaultDragGestureRecognizer (this,                                       DnDConstants.ACTION_MOVE,                                                           this);        dropTarget = new DropTarget (this, this);    }    // DragGestureListener    public void dragGestureRecognized (DragGestureEvent dge) {        System.out.println ("dragGestureRecognized");        // find object at this x,y        Point clickPoint = dge.getDragOrigin();        int index = locationToIndex(clickPoint);        if (index == -1)            return;        Object target = getModel().getElementAt(index);        Transferable trans = new RJLTransferable (target);        draggedIndex = index;        dragSource.startDrag (dge,Cursor.getDefaultCursor(),                              trans, this);    }    // DragSourceListener events    public void dragDropEnd (DragSourceDropEvent dsde) {       System.out.println ("dragDropEnd()");       dropTargetCell = null;       draggedIndex = -1;       repaint();    }public void dragEnter (DragSourceDragEvent dsde) {}    public void dragExit (DragSourceEvent dse) {}    public void dragOver (DragSourceDragEvent dsde) {}    public void dropActionChanged (DragSourceDragEvent dsde) {}    // DropTargetListener events    public void dragEnter (DropTargetDragEvent dtde) {        System.out.println ("dragEnter");        if (dtde.getSource() != dropTarget)            dtde.rejectDrag();        else {            dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);            System.out.println ("accepted dragEnter");        }    }    public void dragExit (DropTargetEvent dte) {}public void dragOver (DropTargetDragEvent dtde) {     // figure out which cell it's over, no drag to self        if (dtde.getSource() != dropTarget)        dtde.rejectDrag();    Point dragPoint = dtde.getLocation();    int index = locationToIndex (dragPoint);    if (index == -1)        dropTargetCell = null;     else                dropTargetCell = getModel().getElementAt(index);        repaint(); }public void drop (DropTargetDropEvent dtde) {        System.out.println ("drop()!");        if (dtde.getSource() != dropTarget) {        System.out.println ("rejecting for bad source (" +                            dtde.getSource().getClass().getName() + ")");                dtde.rejectDrop();         return;    }    Point dropPoint = dtde.getLocation();    int index = locationToIndex (dropPoint);    System.out.println ("drop index is " + index);    boolean dropped = false;    try {        if ((index == -1) || (index == draggedIndex)) {            System.out.println ("dropped onto self");            dtde.rejectDrop();            return;        }        dtde.acceptDrop (DnDConstants.ACTION_MOVE);        System.out.println ("accepted");        Object dragged =           dtde.getTransferable().getTransferData(localObjectFlavor);        // move items - note that indicies for insert will         // change if [removed] source was before target         System.out.println ("drop " + draggedIndex + " to " + index);        boolean sourceBeforeTarget = (draggedIndex < index);         System.out.println ("source is" +                            (sourceBeforeTarget ? "" : " not") +                            " before target");        System.out.println ("insert at " +                            (sourceBeforeTarget ? index-1 : index));         DefaultListModel mod = (DefaultListModel) getModel();         mod.remove (draggedIndex);         mod.add ((sourceBeforeTarget ? index-1 : index), dragged);         dropped = true;    } catch (Exception e) {        e.printStackTrace();    }    dtde.dropComplete (dropped);}    public void dropActionChanged (DropTargetDragEvent dtde) {}public static void main (String[] args) {        JList list = new ReorderableJList ();        DefaultListModel defModel = new DefaultListModel();     list.setModel (defModel);     String[] listItems = {        "Chris", "Joshua", "Daniel", "Michael",        "Don", "Kimi", "Kelly", "Keagan"    };    Iterator it = Arrays.asList(listItems).iterator();    while (it.hasNext())       defModel.addElement (it.next());    // show list    JScrollPane scroller =        new JScrollPane (list,                          ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,                          ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);    JFrame frame = new JFrame ("Checkbox JList");    frame.getContentPane().add (scroller);    frame.pack();    frame.setVisible(true);}class RJLTransferable implements Transferable {     Object object;     public RJLTransferable (Object o) {        object = o;    }    public Object getTransferData(DataFlavor df)        throws UnsupportedFlavorException, IOException {        if (isDataFlavorSupported (df))            return object;        else           throw new UnsupportedFlavorException(df);    }    public boolean isDataFlavorSupported (DataFlavor df) {        return (df.equals (localObjectFlavor));    }    public DataFlavor[] getTransferDataFlavors () {        return supportedFlavors; } }class ReorderableListCellRenderer    extends DefaultListCellRenderer {    boolean isTargetCell;    boolean isLastItem;       public ReorderableListCellRenderer() {       super();   }   public Component getListCellRendererComponent (JList list,                                                  Object value,                                                   int index,                                                   boolean isSelected,                                                  boolean hasFocus) {       isTargetCell = (value == dropTargetCell);       isLastItem = (index == list.getModel().getSize()-1);       boolean showSelected = isSelected &                             (dropTargetCell == null);       return super.getListCellRendererComponent (list, value,                                                   index, showSelected,                                                                                                   hasFocus);   }   public void paintComponent (Graphics g) {       super.paintComponent(g);       if (isTargetCell) {           g.setColor(Color.black);                       g.drawLine (0, 0, getSize().width, 0);        }     } }}