Перетаскивание и перетаскивание Проблемы с переносом Java

Question

Я делал перетаскивание между двумя JTree, чтобы переместить некоторые узлы. Я установил, что он удалит узлы на один раз JTree, когда они будут перемещены в другой. Однако каждый раз, когда я проверяю его, значение моих действий равно 0. Что не так с кодом?

protected void exportDone(JComponent source, Transferable data, int action) 
{ 
    if(action == MOVE) 
    { 
     JTree tree = (JTree)source; 
     TreePath [] paths = tree.getSelectionPaths(); 
     DefaultTreeModel model = (DefaultTreeModel) tree.getModel(); 
     for(TreePath temp : paths) 
     { 
      model.removeNodeFromParent((MutableTreeNode) temp.getLastPathComponent()); 
     } 
    } 
} 

public int getSourceActions(JComponent c) 
{ 
    return MOVE; 
} 

Answer 1

Guess от использования DefaultTreeModel#removeNodeFromParent(...) метода, у вас есть проблемы с, как использовать DefaultTreeModel#insertNodeInto(...):

@Override public boolean importData(TransferSupport support) { 
    if (!canImport(support)) { 
    return false; 
    } 
    DefaultMutableTreeNode[] nodes = null; 
    try { 
    Transferable t = support.getTransferable(); 
     nodes = (DefaultMutableTreeNode[]) t.getTransferData(flavor); 
    } catch (UnsupportedFlavorException | IOException ex) { 
     ex.printStackTrace(); 
    } 

    JTree.DropLocation dl = (JTree.DropLocation) support.getDropLocation(); 
    int childIndex = dl.getChildIndex(); 
    TreePath dest = dl.getPath(); 
    DefaultMutableTreeNode parent = (DefaultMutableTreeNode) dest.getLastPathComponent(); 
    JTree tree = (JTree) support.getComponent(); 
    DefaultTreeModel model = (DefaultTreeModel) tree.getModel(); 

    int index = childIndex; 
    if (childIndex == -1) { 
    index = parent.getChildCount(); 
    } 

    for (DefaultMutableTreeNode node: nodes) { 
    //BAD: model.insertNodeInto(node, parent, index++); 
    //Need to use clone of DefaultMutableTreeNode 
    DefaultMutableTreeNode clone = new DefaultMutableTreeNode(node.getUserObject()); 
    //if !node.isLeaf(): clone = somethingDeepCopyTreeNode(node, clone); 
    model.insertNodeInto(clone, parent, index++); 
    } 
    return true; 
} 

SSCCE

import java.awt.*; 
import java.awt.datatransfer.*; 
import java.awt.event.ActionEvent; 
import java.io.IOException; 
import java.util.*; 
import java.util.List; 
import javax.activation.*; 
import javax.swing.*; 
import javax.swing.tree.*; 

public class TreeDragAndDropTest { 
    private JComponent makeUI() { 
    TreeTransferHandler handler = new TreeTransferHandler(); 
    JPanel p = new JPanel(new GridLayout(1, 2)); 
    p.add(new JScrollPane(makeTree(handler))); 
    p.add(new JScrollPane(makeTree(handler))); 
    return p; 
    } 

    private static JTree makeTree(TransferHandler hanlder) { 
    JTree tree = new JTree(); 
    tree.setRootVisible(false); 
    tree.setDragEnabled(true); 
    tree.setTransferHandler(hanlder); 
    tree.setDropMode(DropMode.INSERT); 
    tree.getSelectionModel().setSelectionMode(
     TreeSelectionModel.SINGLE_TREE_SELECTION); 
    expandTree(tree); 
    return tree; 
    } 

    public static void expandTree(JTree tree) { 
    for (int i = 0; i < tree.getRowCount(); i++) { 
     tree.expandRow(i); 
    } 
    } 

    public static void main(String... args) { 
    EventQueue.invokeLater(() -> { 
     JFrame f = new JFrame(); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     f.add(new TreeDragAndDropTest().makeUI()); 
     f.setSize(320, 240); 
     f.setLocationRelativeTo(null); 
     f.setVisible(true); 
    }); 
    } 
} 

class TreeTransferHandler extends TransferHandler { 
    private static final DataFlavor localObjectFlavor = new ActivationDataFlavor(
    DefaultMutableTreeNode[].class, 
    DataFlavor.javaJVMLocalObjectMimeType, 
    "Array of DefaultMutableTreeNode"); 
    private JTree source; 

    @Override protected Transferable createTransferable(JComponent c) { 
    source = (JTree) c; 
    TreePath[] paths = source.getSelectionPaths(); 
    DefaultMutableTreeNode[] nodes = new DefaultMutableTreeNode[paths.length]; 
    for (int i = 0; i < paths.length; i++) { 
     nodes[i] = (DefaultMutableTreeNode) paths[i].getLastPathComponent(); 
    } 
    return new DataHandler(nodes, localObjectFlavor.getMimeType()); 
    } 

    @Override public int getSourceActions(JComponent c) { 
    return MOVE; 
    } 

    @Override public boolean canImport(TransferSupport support) { 
    if (!support.isDrop()) { 
     return false; 
    } 
    if (!support.isDataFlavorSupported(localObjectFlavor)) { 
     return false; 
    } 
    JTree.DropLocation dl = (JTree.DropLocation) support.getDropLocation(); 
    JTree tree = (JTree) support.getComponent(); 
    return !tree.equals(source); 
    } 

    @Override public boolean importData(TransferSupport support) { 
    if (!canImport(support)) { 
     return false; 
    } 
    DefaultMutableTreeNode[] nodes = null; 
    try { 
     Transferable t = support.getTransferable(); 
     nodes = (DefaultMutableTreeNode[]) t.getTransferData(localObjectFlavor); 
    } catch (UnsupportedFlavorException | IOException ex) { 
     ex.printStackTrace(); 
    } 

    JTree.DropLocation dl = (JTree.DropLocation) support.getDropLocation(); 
    int childIndex = dl.getChildIndex(); 
    TreePath dest = dl.getPath(); 
    DefaultMutableTreeNode parent = 
     (DefaultMutableTreeNode) dest.getLastPathComponent(); 
    JTree tree = (JTree) support.getComponent(); 
    DefaultTreeModel model = (DefaultTreeModel) tree.getModel(); 
    int idx = childIndex < 0 ? parent.getChildCount() : childIndex; 
    //DefaultTreeModel sm = (DefaultTreeModel) source.getModel(); 
    for (DefaultMutableTreeNode node : nodes) { 
     //sm.removeNodeFromParent(node); 
     //model.insertNodeInto(node, parent, idx++); 

     DefaultMutableTreeNode clone = new DefaultMutableTreeNode(node.getUserObject()); 
     model.insertNodeInto(deepCopyTreeNode(node, clone), parent, idx++); 
    } 
    return true; 
    } 
    private static DefaultMutableTreeNode deepCopyTreeNode(
     DefaultMutableTreeNode src, DefaultMutableTreeNode tgt) { 
    for (int i = 0; i < src.getChildCount(); i++) { 
     DefaultMutableTreeNode node = (DefaultMutableTreeNode) src.getChildAt(i); 
     DefaultMutableTreeNode clone = new DefaultMutableTreeNode(node.getUserObject()); 
     tgt.add(clone); 
     if (!node.isLeaf()) { 
     deepCopyTreeNode(node, clone); 
     } 
    } 
    return tgt; 
    } 
    @Override protected void exportDone(JComponent source, Transferable data, int action) { 
    if (action == MOVE) { 
     JTree tree = (JTree) source; 
     DefaultTreeModel model = (DefaultTreeModel) tree.getModel(); 
     for (TreePath path : tree.getSelectionPaths()) { 
     model.removeNodeFromParent((MutableTreeNode) path.getLastPathComponent()); 
     } 
    } 
    } 
}