Question

我正在尝试动态地将节点添加到弹出组件内的JTree和JMenuItem组件的click动作事件中。我右键单击节点组件并添加另一个节点。节点的添加适用于叶节点，但不适用于非叶节点。我不知道代码有什么问题。似乎添加了节点，但Gui没有更新。

平台： Windows 7

爪哇 java版“1.7.0_17” Java（TM）SE运行时环境（版本1.7.0_17-b02） Java HotSpot（TM）64位服务器VM（内置23.7-b01，混合模式）

package test;

/**
 *
 * @author Rajan
 */

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.MutableTreeNode;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;

/**
 *
 * @author Rajan Prasad Upadhyay
 */
public class TreeTest {

    String name = "name";

    public static void main(String[] args) {
        javax.swing.JFrame topFrame = new JFrame();
        javax.swing.JPanel topPanel = new JPanel();
        javax.swing.JScrollPane leftScrollPane = new JScrollPane();
        javax.swing.JTree leftTree = new JTree();

        topFrame.setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        //layouts
        topFrame.setLayout(new BorderLayout());
        topPanel.setLayout(new BorderLayout());

        // addition of components
//        topPanel.setMaximumSize(new Dimension(Integer.MAX_VALUE,Integer.MAX_VALUE));
        topPanel.add(leftScrollPane);

        leftScrollPane.getViewport().add(leftTree);

        addExperimentEvents(leftTree);

        topFrame.setSize(600, 500);
        topFrame.setContentPane(topPanel);
        topFrame.setVisible(true);
    }

    public static void addExperimentEvents(JTree tree) {
        MouseAdapter ma = new MouseAdapter() {
            private void myPopupEvent(MouseEvent e) {
                int x = e.getX();
                int y = e.getY();
                final JTree tree = (JTree) e.getSource();
                TreePath path = tree.getPathForLocation(x, y);
                if (path == null) {
                    return;
                }

                tree.setSelectionPath(path);

                Object obj = (Object) path.getLastPathComponent();

                String label = "Add:";// + obj.toString();
                JPopupMenu popup = new JPopupMenu("Menu");

                JMenu sectionsMenu = new JMenu("Sections");
                JMenuItem menuItem1 = new JMenuItem("Item1");
                sectionsMenu.add(menuItem1);
                JMenuItem menuItem2 = new JMenuItem("Item2");
                sectionsMenu.add(menuItem2);

                JMenuItem item = new JMenuItem(label);
                item.addActionListener(new ActionListener() {

                    @Override
                    public void actionPerformed(ActionEvent ae) {
                        System.out.println("Editing the tree");
                        DefaultMutableTreeNode selNode = (DefaultMutableTreeNode) tree
                                .getLastSelectedPathComponent();
                        TreeNode root = (TreeNode) tree.getModel().getRoot();
                        DefaultTreeModel model = new DefaultTreeModel(root);

                        if (selNode != null) {
                            DefaultMutableTreeNode newNode = new DefaultMutableTreeNode("New Node" + (selNode.getChildCount() + 1));
                            model.insertNodeInto(newNode, selNode, selNode.getChildCount());//
                            //model.insertNodeInto(newNode, (MutableTreeNode) root, root.getChildCount());
                            tree.expandPath(new TreePath(model.getPathToRoot(newNode.getParent())));

                            TreeNode[] nodes = model.getPathToRoot(newNode);
                            TreePath path = new TreePath(nodes);

                            System.out.println(selNode.getChildCount() + ", " + path);
                            tree.scrollPathToVisible(path);
                            tree.setSelectionPath(path);
                            tree.startEditingAtPath(path);
                            model.reload((TreeNode) model.getRoot());
                        }else{
                            System.out.println("selNode is null");
                        }
                    }
                });
                //addHoverAction(item);//
                //item.add(new JMenuItem("page"));

                popup.add(item);
                popup.add(new JMenuItem("Move: "));
                popup.add(sectionsMenu);
                popup.show(tree, x, y);
            }

            public void mousePressed(MouseEvent e) {
                if (e.isPopupTrigger()) {
                    myPopupEvent(e);
                }
            }

            public void mouseReleased(MouseEvent e) {
                if (e.isPopupTrigger()) {
                    myPopupEvent(e);
                }
            }
        };
        tree.addMouseListener(ma);
    }

    public static void addHoverAction(final JComponent com) {

        MouseAdapter adapter = new MouseAdapter() {
            public void mouseEntered(java.awt.event.MouseEvent evt) {
                System.out.println("mouse Entered: ");
                if (true) {
                    JPopupMenu pop = new JPopupMenu();
                    pop.add(new JMenuItem("Node"));

                    pop.show(com.getParent(), com.getWidth(), com.getHeight());
                }
            }
        };
        com.addMouseListener(adapter);
    }
}

首先感谢您提供解决方案和问题描述。

Answer 1

使用以下行

DefaultTreeModel model = (DefaultTreeModel) tree.getModel();

而不是

DefaultTreeModel model = new DefaultTreeModel(root);

最后展开所需的节点。

以下是关于How to expand or collapse all JTree nodes?

的示例代码

Answer 2

有一个Swing tutorial that does exactly that。您可以看到它们用于动态添加，删除和编辑树的完整代码。他们的代码很短。

动态添加节点到非叶节点不工作| JTree的

2 个答案: