将子节点插入 JTree TreeNode 并更新视图

Question

我得到以下代码 [减少到最低限度]：

public class MainWindow extends JFrame {

    private static String StrBenutzer;
    private JPanel contentPane;

    TreeNode TreeNodeRoot = createInitTree();
    JTree tree = new JTree(TreeNodeRoot);


    static DefaultMutableTreeNode NodeRoot;
    static DefaultMutableTreeNode NodeProjekte;
    static DefaultMutableTreeNode NodeAllgemein;



    /**
     * Launch the application.
     */
    public static void initWindow() {



        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MainWindow frame = new MainWindow();
                    frame.setExtendedState(JFrame.MAXIMIZED_BOTH); 
                    frame.setUndecorated(false);
                    frame.setVisible(true);
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public MainWindow() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 1160, 679);


        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        SpringLayout sl_contentPane = new SpringLayout();
        contentPane.setLayout(sl_contentPane);



        sl_contentPane.putConstraint(SpringLayout.NORTH, tree, 0, SpringLayout.NORTH, contentPane);
        tree.setEditable(true);
        contentPane.add(tree);

        JButton btnAdd = new JButton("Add");
        sl_contentPane.putConstraint(SpringLayout.WEST, tree, 0, SpringLayout.WEST, btnAdd);
        sl_contentPane.putConstraint(SpringLayout.SOUTH, tree, -11, SpringLayout.NORTH, btnAdd);
        sl_contentPane.putConstraint(SpringLayout.WEST, btnAdd, 0, SpringLayout.WEST, contentPane);
        sl_contentPane.putConstraint(SpringLayout.SOUTH, btnAdd, -10, SpringLayout.SOUTH, contentPane);
        contentPane.add(btnAdd);

        JButton btnDelete = new JButton("Delete");
        sl_contentPane.putConstraint(SpringLayout.NORTH, btnDelete, 0, SpringLayout.NORTH, btnAdd);
        sl_contentPane.putConstraint(SpringLayout.WEST, btnDelete, 6, SpringLayout.EAST, btnAdd);
        contentPane.add(btnDelete);

        JButton btnInfo = new JButton("Info");
        sl_contentPane.putConstraint(SpringLayout.EAST, tree, 1, SpringLayout.EAST, btnInfo);
        sl_contentPane.putConstraint(SpringLayout.NORTH, btnInfo, 0, SpringLayout.NORTH, btnAdd);
        sl_contentPane.putConstraint(SpringLayout.WEST, btnInfo, 6, SpringLayout.EAST, btnDelete);
        sl_contentPane.putConstraint(SpringLayout.EAST, btnInfo, 59, SpringLayout.EAST, btnDelete);
        contentPane.add(btnInfo);

        JPanel panel = new JPanel();
        sl_contentPane.putConstraint(SpringLayout.NORTH, panel, 0, SpringLayout.NORTH, tree);
        sl_contentPane.putConstraint(SpringLayout.WEST, panel, 16, SpringLayout.EAST, tree);
        sl_contentPane.putConstraint(SpringLayout.SOUTH, panel, 565, SpringLayout.NORTH, contentPane);
        sl_contentPane.putConstraint(SpringLayout.EAST, panel, 39, SpringLayout.EAST, contentPane);
        contentPane.add(panel);
    }




    private static TreeNode createInitTree(){


        NodeRoot = new DefaultMutableTreeNode("User");
        NodeProjekte = new DefaultMutableTreeNode( "Projekte");
        NodeAllgemein = new DefaultMutableTreeNode( "Allgemein" );

        DefaultMutableTreeNode projectA = new DefaultMutableTreeNode("Projekt A");
        DefaultMutableTreeNode projectB = new DefaultMutableTreeNode("Projekt B");

        DefaultMutableTreeNode LinkProjectA = new DefaultMutableTreeNode("Öffnen");
        DefaultMutableTreeNode LinkProjektB = new DefaultMutableTreeNode("Öffnen");

        DefaultMutableTreeNode NotizProjektA = new DefaultMutableTreeNode("Notiz");
        DefaultMutableTreeNode NoitzProjektB = new DefaultMutableTreeNode("Notiz");

        DefaultMutableTreeNode Zeitstrahl = new DefaultMutableTreeNode("Zeitplan");
        DefaultMutableTreeNode ToDo = new DefaultMutableTreeNode("ToDo");

        NodeProjekte.add( projectA );
        NodeProjekte.add( projectB );

        projectA.add(LinkProjectA);
        projectA.add(NotizProjektA);

        projectB.add(LinkProjektB);
        projectB.add(NoitzProjektB);

        NodeAllgemein.add(Zeitstrahl);
        NodeAllgemein.add(ToDo);

        NodeRoot.add( NodeProjekte );
        NodeRoot.add( NodeAllgemein );

        return NodeRoot;
    }




    private static void addItem(String StrProjektLink, String StrProjektName){

        DefaultMutableTreeNode NodeNewProject = new DefaultMutableTreeNode(StrProjektName);
        DefaultMutableTreeNode NodeNewProjectLink = new DefaultMutableTreeNode("Link");
        DefaultMutableTreeNode NodeNewProjectNotiz = new DefaultMutableTreeNode("Notiz");

        NodeProjekte.add(NodeNewProject);
        NodeNewProject.add(NodeNewProjectLink);
        NodeNewProject.add(NodeNewProjectNotiz);






    }


    private static void deleteItem(){

    }

    private static void updateTree(){


    }




    private void addProjectFolder()
    {

    addItem("C:/Users/", "User-Directory"a);

    }




}

现在我想在从树中添加或删除一个孩子之后更新 JTree 模型。但是 Eclipse 说，我所有的变量和函数都必须是静态的，所以我不能更新元素。更新 JTree 最简单的方法是什么？

Answer 1

您的问题看起来与 Swing 或 JTree 无关，而与静态与实例字段和方法的使用和滥用有关。在我看来，最好的解决方案是将所有字段设为私有实例字段，并将所有方法设为实例方法之上，除了 initWindow() 方法。那么解决方案就会失效。

// !! make everything private and nothing static
// also follow Java naming conventions
private TreeNode treeNodeRoot = createInitTree();
private JTree tree = new JTree(treeNodeRoot);
private DefaultMutableTreeNode nodeRoot;
private DefaultMutableTreeNode nodeProjekte;
private DefaultMutableTreeNode nodeAllgemein;


private class AddAction implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        String message = "Enter node name:";
        String nodeName = JOptionPane.showInputDialog(MainWindow.this, message);

        // ...

        DefaultMutableTreeNode parentNode = null;
        TreePath parentPath = tree.getSelectionPath();

        // ....

        DefaultMutableTreeNode childNode = new DefaultMutableTreeNode(nodeName);
        int index = parentNode.getChildCount();
        DefaultTreeModel treeModel = (DefaultTreeModel) tree.getModel();
        treeModel.insertNodeInto(childNode, parentNode, index);
    }
}