Các nút Kéo và Thả trong JTree

Question

Tôi gặp khó khăn khi tạo một JTree cho phép các nút được tổ chức lại bằng cách kéo và thả chúng trong JTree. Điều này có vẻ như nó tương đối đơn giản. Tôi đã xem xét các ví dụ trực tuyến, nhưng tôi dường như không thể thực hiện nó trong mã của riêng tôi.

Ví dụ: this do mặt trời cung cấp cho phép kéo giữa các thành phần khác nhau vào cây, nhưng không phải từ bên trong thân cây.

Và tôi cũng đã tìm thấy điều này cho phép bạn kéo văn bản vào JTree, nhưng không phải trong cây.

 

 

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

public class DndTree { 

    public static void main(String args[]) { 
     Runnable runner = new Runnable() { 

      public void run() { 
       JFrame f = new JFrame("D-n-D JTree"); 
       f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

       JPanel top = new JPanel(new BorderLayout()); 
       JLabel dragLabel = new JLabel("Drag me:"); 
       JTextField text = new JTextField(); 
       text.setDragEnabled(true); 
       top.add(dragLabel, BorderLayout.WEST); 
       top.add(text, BorderLayout.CENTER); 
       f.add(top, BorderLayout.NORTH); 

       final JTree tree = new JTree(); 
       final DefaultTreeModel model = (DefaultTreeModel) tree.getModel(); 
       tree.setTransferHandler(new TransferHandler() { 

        public boolean canImport(TransferHandler.TransferSupport support) { 
         if (!support.isDataFlavorSupported(DataFlavor.stringFlavor) 
           || !support.isDrop()) { 
          return false; 
         } 

         JTree.DropLocation dropLocation = 
           (JTree.DropLocation) support.getDropLocation(); 

         return dropLocation.getPath() != null; 
        } 

        public boolean importData(TransferHandler.TransferSupport support) { 
         if (!canImport(support)) { 
          return false; 
         } 

         JTree.DropLocation dropLocation = 
           (JTree.DropLocation) support.getDropLocation(); 

         TreePath path = dropLocation.getPath(); 

         Transferable transferable = support.getTransferable(); 

         String transferData; 
         try { 
          transferData = (String) transferable.getTransferData(
            DataFlavor.stringFlavor); 
         } catch (IOException e) { 
          return false; 
         } catch (UnsupportedFlavorException e) { 
          return false; 
         } 

         int childIndex = dropLocation.getChildIndex(); 
         if (childIndex == -1) { 
          childIndex = model.getChildCount(path.getLastPathComponent()); 
         } 

         DefaultMutableTreeNode newNode = 
           new DefaultMutableTreeNode(transferData); 
         DefaultMutableTreeNode parentNode = 
           (DefaultMutableTreeNode) path.getLastPathComponent(); 
         model.insertNodeInto(newNode, parentNode, childIndex); 

         TreePath newPath = path.pathByAddingChild(newNode); 
         tree.makeVisible(newPath); 
         tree.scrollRectToVisible(tree.getPathBounds(newPath)); 

         return true; 
        } 
       }); 

       JScrollPane pane = new JScrollPane(tree); 
       f.add(pane, BorderLayout.CENTER); 

       JPanel bottom = new JPanel(); 
       JLabel comboLabel = new JLabel("DropMode"); 
       String options[] = {"USE_SELECTION", 
        "ON", "INSERT", "ON_OR_INSERT" 
       }; 
       final DropMode mode[] = {DropMode.USE_SELECTION, 
        DropMode.ON, DropMode.INSERT, DropMode.ON_OR_INSERT}; 
       final JComboBox combo = new JComboBox(options); 
       combo.addActionListener(new ActionListener() { 

        public void actionPerformed(ActionEvent e) { 
         int selectedIndex = combo.getSelectedIndex(); 
         tree.setDropMode(mode[selectedIndex]); 
        } 
       }); 
       bottom.add(comboLabel); 
       bottom.add(combo); 
       f.add(bottom, BorderLayout.SOUTH); 
       f.setSize(300, 400); 
       f.setVisible(true); 
      } 
     }; 
     EventQueue.invokeLater(runner); 
    } 
} 

Mọi tham chiếu hoặc đề xuất sẽ tuyệt vời. Cảm ơn

Answer 1

Bạn chưa từng làm điều này trước đây, nhưng tìm kiếm nhanh trên google đã xuất hiện cùng một câu hỏi tại đây: http://www.coderanch.com/t/346509/GUI/java/JTree-drag-drop-inside-one nó có triển khai hoạt động mà bạn có thể xem.

Đây là mã có liên quan mà Craig Gỗ gửi:

import java.awt.*; 
import java.awt.datatransfer.*; 
import java.awt.dnd.*; 
import java.util.*; 
import java.util.List; 
import javax.swing.*; 
import javax.swing.tree.*; 

public class TreeDragAndDrop { 
    private JScrollPane getContent() { 
     JTree tree = new JTree(); 
     tree.setDragEnabled(true); 
     tree.setDropMode(DropMode.ON_OR_INSERT); 
     tree.setTransferHandler(new TreeTransferHandler()); 
     tree.getSelectionModel().setSelectionMode(
       TreeSelectionModel.CONTIGUOUS_TREE_SELECTION); 
     expandTree(tree); 
     return new JScrollPane(tree); 
    } 

    private void expandTree(JTree tree) { 
     DefaultMutableTreeNode root = 
      (DefaultMutableTreeNode)tree.getModel().getRoot(); 
     Enumeration e = root.breadthFirstEnumeration(); 
     while(e.hasMoreElements()) { 
      DefaultMutableTreeNode node = 
       (DefaultMutableTreeNode)e.nextElement(); 
      if(node.isLeaf()) continue; 
      int row = tree.getRowForPath(new TreePath(node.getPath())); 
      tree.expandRow(row); 
     } 
    } 

    public static void main(String[] args) { 
     JFrame f = new JFrame(); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     f.add(new TreeDragAndDrop().getContent()); 
     f.setSize(400,400); 
     f.setLocation(200,200); 
     f.setVisible(true); 
    } 
} 

class TreeTransferHandler extends TransferHandler { 
    DataFlavor nodesFlavor; 
    DataFlavor[] flavors = new DataFlavor[1]; 
    DefaultMutableTreeNode[] nodesToRemove; 

    public TreeTransferHandler() { 
     try { 
      String mimeType = DataFlavor.javaJVMLocalObjectMimeType + 
           ";class=\"" + 
       javax.swing.tree.DefaultMutableTreeNode[].class.getName() + 
           "\""; 
      nodesFlavor = new DataFlavor(mimeType); 
      flavors[0] = nodesFlavor; 
     } catch(ClassNotFoundException e) { 
      System.out.println("ClassNotFound: " + e.getMessage()); 
     } 
    } 

    public boolean canImport(TransferHandler.TransferSupport support) { 
     if(!support.isDrop()) { 
      return false; 
     } 
     support.setShowDropLocation(true); 
     if(!support.isDataFlavorSupported(nodesFlavor)) { 
      return false; 
     } 
     // Do not allow a drop on the drag source selections. 
     JTree.DropLocation dl = 
       (JTree.DropLocation)support.getDropLocation(); 
     JTree tree = (JTree)support.getComponent(); 
     int dropRow = tree.getRowForPath(dl.getPath()); 
     int[] selRows = tree.getSelectionRows(); 
     for(int i = 0; i < selRows.length; i++) { 
      if(selRows[i] == dropRow) { 
       return false; 
      } 
     } 
     // Do not allow MOVE-action drops if a non-leaf node is 
     // selected unless all of its children are also selected. 
     int action = support.getDropAction(); 
     if(action == MOVE) { 
      return haveCompleteNode(tree); 
     } 
     // Do not allow a non-leaf node to be copied to a level 
     // which is less than its source level. 
     TreePath dest = dl.getPath(); 
     DefaultMutableTreeNode target = 
      (DefaultMutableTreeNode)dest.getLastPathComponent(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode firstNode = 
      (DefaultMutableTreeNode)path.getLastPathComponent(); 
     if(firstNode.getChildCount() > 0 && 
       target.getLevel() < firstNode.getLevel()) { 
      return false; 
     } 
     return true; 
    } 

    private boolean haveCompleteNode(JTree tree) { 
     int[] selRows = tree.getSelectionRows(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode first = 
      (DefaultMutableTreeNode)path.getLastPathComponent(); 
     int childCount = first.getChildCount(); 
     // first has children and no children are selected. 
     if(childCount > 0 && selRows.length == 1) 
      return false; 
     // first may have children. 
     for(int i = 1; i < selRows.length; i++) { 
      path = tree.getPathForRow(selRows[i]); 
      DefaultMutableTreeNode next = 
       (DefaultMutableTreeNode)path.getLastPathComponent(); 
      if(first.isNodeChild(next)) { 
       // Found a child of first. 
       if(childCount > selRows.length-1) { 
        // Not all children of first are selected. 
        return false; 
       } 
      } 
     } 
     return true; 
    } 

    protected Transferable createTransferable(JComponent c) { 
     JTree tree = (JTree)c; 
     TreePath[] paths = tree.getSelectionPaths(); 
     if(paths != null) { 
      // Make up a node array of copies for transfer and 
      // another for/of the nodes that will be removed in 
      // exportDone after a successful drop. 
      List<DefaultMutableTreeNode> copies = 
       new ArrayList<DefaultMutableTreeNode>(); 
      List<DefaultMutableTreeNode> toRemove = 
       new ArrayList<DefaultMutableTreeNode>(); 
      DefaultMutableTreeNode node = 
       (DefaultMutableTreeNode)paths[0].getLastPathComponent(); 
      DefaultMutableTreeNode copy = copy(node); 
      copies.add(copy); 
      toRemove.add(node); 
      for(int i = 1; i < paths.length; i++) { 
       DefaultMutableTreeNode next = 
        (DefaultMutableTreeNode)paths[i].getLastPathComponent(); 
       // Do not allow higher level nodes to be added to list. 
       if(next.getLevel() < node.getLevel()) { 
        break; 
       } else if(next.getLevel() > node.getLevel()) { // child node 
        copy.add(copy(next)); 
        // node already contains child 
       } else {          // sibling 
        copies.add(copy(next)); 
        toRemove.add(next); 
       } 
      } 
      DefaultMutableTreeNode[] nodes = 
       copies.toArray(new DefaultMutableTreeNode[copies.size()]); 
      nodesToRemove = 
       toRemove.toArray(new DefaultMutableTreeNode[toRemove.size()]); 
      return new NodesTransferable(nodes); 
     } 
     return null; 
    } 

    /** Defensive copy used in createTransferable. */ 
    private DefaultMutableTreeNode copy(TreeNode node) { 
     return new DefaultMutableTreeNode(node); 
    } 

    protected void exportDone(JComponent source, Transferable data, int action) { 
     if((action & MOVE) == MOVE) { 
      JTree tree = (JTree)source; 
      DefaultTreeModel model = (DefaultTreeModel)tree.getModel(); 
      // Remove nodes saved in nodesToRemove in createTransferable. 
      for(int i = 0; i < nodesToRemove.length; i++) { 
       model.removeNodeFromParent(nodesToRemove[i]); 
      } 
     } 
    } 

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

    public boolean importData(TransferHandler.TransferSupport support) { 
     if(!canImport(support)) { 
      return false; 
     } 
     // Extract transfer data. 
     DefaultMutableTreeNode[] nodes = null; 
     try { 
      Transferable t = support.getTransferable(); 
      nodes = (DefaultMutableTreeNode[])t.getTransferData(nodesFlavor); 
     } catch(UnsupportedFlavorException ufe) { 
      System.out.println("UnsupportedFlavor: " + ufe.getMessage()); 
     } catch(java.io.IOException ioe) { 
      System.out.println("I/O error: " + ioe.getMessage()); 
     } 
     // Get drop location info. 
     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(); 
     // Configure for drop mode. 
     int index = childIndex; // DropMode.INSERT 
     if(childIndex == -1) {  // DropMode.ON 
      index = parent.getChildCount(); 
     } 
     // Add data to model. 
     for(int i = 0; i < nodes.length; i++) { 
      model.insertNodeInto(nodes[i], parent, index++); 
     } 
     return true; 
    } 

    public String toString() { 
     return getClass().getName(); 
    } 

    public class NodesTransferable implements Transferable { 
     DefaultMutableTreeNode[] nodes; 

     public NodesTransferable(DefaultMutableTreeNode[] nodes) { 
      this.nodes = nodes; 
     } 

     public Object getTransferData(DataFlavor flavor) 
           throws UnsupportedFlavorException { 
      if(!isDataFlavorSupported(flavor)) 
       throw new UnsupportedFlavorException(flavor); 
      return nodes; 
     } 

     public DataFlavor[] getTransferDataFlavors() { 
      return flavors; 
     } 

     public boolean isDataFlavorSupported(DataFlavor flavor) { 
      return nodesFlavor.equals(flavor); 
     } 
    } 
}