另一个例子：
编辑：修复光标闪烁
import java.awt.*;import java.awt.datatransfer.*;import java.awt.dnd.*;import java.awt.event.*;import java.io.*;import java.util.*;import javax.activation.*;import javax.swing.*;import javax.swing.text.*;public class DragTest3 { public JComponent makeUI() { DragPanel p1 = new DragPanel(); p1.setBorder(BorderFactory.createLineBorder(Color.BLACK)); p1.add(new JLabel(UIManager.getIcon("OptionPane.warningIcon"))); p1.add(new JLabel(UIManager.getIcon("OptionPane.errorIcon"))); p1.add(new JLabel("Label1")); p1.add(new JLabel("Label2")); MouseListener handler = new Handler(); p1.addMouseListener(handler); LabelTransferHandler th = new LabelTransferHandler(); p1.setTransferHandler(th); JPanel p = new JPanel(new GridLayout(1,2)); p.add(p1); DragPanel p2 = new DragPanel(); p2.setBorder(BorderFactory.createLineBorder(Color.BLACK)); p2.addMouseListener(handler); p2.setTransferHandler(th); p.add(p2); JPanel panel = new JPanel(new GridLayout(2,1)); panel.add(p); panel.add(new JScrollPane(new Jtextarea())); return panel; } public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { createAndShowGUI(); } }); } public static void createAndShowGUI() { Jframe f = new Jframe(); f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); f.getContentPane().add(new DragTest3().makeUI()); f.setSize(320, 240); f.setLocationRelativeTo(null); f.setVisible(true); }}class DragPanel extends JPanel { public DragPanel() { super(); } public JLabel draggingLabel;}class Handler extends MouseAdapter { @Override public void mousePressed(MouseEvent e) { DragPanel p = (DragPanel)e.getSource(); Component c = SwingUtilities.getDeepestComponentAt(p, e.getX(), e.getY()); if(c!=null && c instanceof JLabel) { p.draggingLabel = (JLabel)c; p.getTransferHandler().exportAsDrag(p, e, TransferHandler.MOVE); } }}class LabelTransferHandler extends TransferHandler { private final DataFlavor localObjectFlavor; private final JLabel label = new JLabel() { @Override public boolean contains(int x, int y) { return false; } }; private final JWindow window = new JWindow(); public LabelTransferHandler() { System.out.println("LabelTransferHandler"); localObjectFlavor = new ActivationDataFlavor( DragPanel.class, DataFlavor.javaJVMLocalObjectMimeType, "JLabel"); window.add(label); window.setAlwaysonTop(true); window.setBackground(new Color(0,true)); DragSource.getDefaultDragSource().addDragSourceMotionListener( new DragSourceMotionListener() { @Override public void dragMouseMoved(DragSourceDragEvent dsde) { Point pt = dsde.getLocation(); pt.translate(5, 5); // offset window.setLocation(pt); } }); } @Override protected Transferable createTransferable(JComponent c) { System.out.println("createTransferable"); DragPanel p = (DragPanel)c; JLabel l = p.draggingLabel; String text = l.getText(); //TEST //if(text==null) { // text = l.getIcon().toString(); //} //return new StringSelection(text+"n"); final DataHandler dh = new DataHandler(c, localObjectFlavor.getMimeType()); if(text==null) return dh; final StringSelection ss = new StringSelection(text+"n"); return new Transferable() { @Override public DataFlavor[] getTransferDataFlavors() { ArrayList<DataFlavor> list = new ArrayList<>(); for(DataFlavor f:ss.getTransferDataFlavors()) { list.add(f); } for(DataFlavor f:dh.getTransferDataFlavors()) { list.add(f); } return list.toArray(dh.getTransferDataFlavors()); } public boolean isDataFlavorSupported(DataFlavor flavor) { for (DataFlavor f: getTransferDataFlavors()) { if (flavor.equals(f)) { return true; } } return false; } public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException { if(flavor.equals(localObjectFlavor)) { return dh.getTransferData(flavor); } else { return ss.getTransferData(flavor); } } }; } @Override public boolean canimport(TransferSupport support) { if(!support.isDrop()) { return false; } return true; } @Override public int getSourceActions(JComponent c) { System.out.println("getSourceActions"); DragPanel p = (DragPanel)c; label.setIcon(p.draggingLabel.getIcon()); label.setText(p.draggingLabel.getText()); window.pack(); Point pt = p.draggingLabel.getLocation(); SwingUtilities.convertPointToScreen(pt, p); window.setLocation(pt); window.setVisible(true); return MOVE; } @Override public boolean importData(TransferSupport support) { System.out.println("importData"); if(!canimport(support)) return false; DragPanel target = (DragPanel)support.getComponent(); try { DragPanel src = (DragPanel)support.getTransferable().getTransferData(localObjectFlavor); JLabel l = new JLabel(); l.setIcon(src.draggingLabel.getIcon()); l.setText(src.draggingLabel.getText()); target.add(l); target.revalidate(); return true; } catch(UnsupportedFlavorException ufe) { ufe.printStackTrace(); } catch(java.io.IOException ioe) { ioe.printStackTrace(); } return false; } @Override protected void exportDone(JComponent c, Transferable data, int action) { System.out.println("exportDone"); DragPanel src = (DragPanel)c; if(action == TransferHandler.MOVE) { src.remove(src.draggingLabel); src.revalidate(); src.repaint(); } src.draggingLabel = null; window.setVisible(false); }}
