将节点从Jtree拖到Swing中

Question

I have read and found many ways to drag JComponent s into other JComponent s or drag files onto my JComponent s from the OS to the java application. However I would like to drag a node of my jtree outside of my application into a directory. My nodes represent files so i'd like to save them in the directory they have been dragged.

Does anyone know of a way to do so using the TransferHandler ?

The method public void exportDone(JComponent c, Transferable t, int action) does not allow me to find out into what path the file (node) was dragged naturally...

Answer 1

The method public void exportDone(JComponent c, Transferable t, int action) does not allow me to find out into what path the file (node) was dragged naturally...

• You might be able to use the TransferHandler#createTransferable(JComponent c) method:
• Export Methods (The Java™ Tutorials > Creating a GUI With JFC/Swing > Drag and Drop and Data Transfer)

import java.awt.*;
import java.awt.datatransfer.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.tree.*;

public class TreeDragAndDropTest {
  public JComponent makeUI() {
    JTree tree = new JTree();
    tree.getSelectionModel().setSelectionMode(
        TreeSelectionModel.SINGLE_TREE_SELECTION);
    tree.setDragEnabled(true);
    tree.setTransferHandler(new TransferHandler() {
      private File f;
      @Override public int getSourceActions(JComponent c) {
        return COPY;
      }
      @Override protected Transferable createTransferable(JComponent c) {
        TreePath p = ((JTree) c).getSelectionPath();
        DefaultMutableTreeNode n = (DefaultMutableTreeNode) p.getLastPathComponent();
        try {
          f = File.createTempFile(Objects.toString(n.getUserObject()) + "_", ".tmp");
        } catch (IOException ex) {
          ex.printStackTrace();
        }
        if (Objects.nonNull(f)) {
          return new Transferable() {
            @Override public Object getTransferData(DataFlavor flavor) {
              return Arrays.asList(f);
            }
            @Override public DataFlavor[] getTransferDataFlavors() {
              return new DataFlavor[] { DataFlavor.javaFileListFlavor };
            }
            @Override public boolean isDataFlavorSupported(DataFlavor flavor) {
              return flavor.equals(DataFlavor.javaFileListFlavor);
            }
          };
        } else {
          return null;
        }
      }
      @Override protected void exportDone(JComponent c, Transferable d, int a) {
        if (Objects.nonNull(f)) {
          f.delete();
        }
      }
    });
    JPanel p = new JPanel(new BorderLayout());
    p.add(new JScrollPane(tree));
    return p;
  }
  public static void main(String... args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new TreeDragAndDropTest().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}