java - 使用 `nodeChanged` 更新树节点是否合适

Question

我有一个 JTree 和一个 JTextField。当我在树上选择一个节点时，文本字段将显示该节点的值。然后我可以编辑文本并保存它以更改所选节点的值。我使用 DefaultTreeModel 的 nodeChanged 方法来更新树。

这是告诉树模型更新其节点的正确方法吗？对我来说，它看起来很难看，因为我正在显式访问树的模型并告诉它发生了什么事。

这是一些代码

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.ScrollPaneConstants;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;

public class TextPaneTest extends JFrame {

    private JTextField textBox = null;
    private JTree tree = null;
    private JButton button = null;

    public static void main(String args[]) {
        new TextPaneTest();
    }

    public TextPaneTest() {

        // Main panel
        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());

        // Panel holding tree
        JPanel treePanel = new JPanel();
        treePanel.setLayout(new BorderLayout());

        // Panel holding text field and button

        JPanel editPanel = new JPanel();
        editPanel.setLayout(new BorderLayout());

        // My textbox
        textBox = new JTextField();

        // button
        button = new JButton();
        button.setText("Save changes");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e)
            {
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();
                String text = textBox.getText();
                node.setUserObject(text);
                DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
                model.nodeChanged(node);
            }
        });

        // My Tree
        DefaultMutableTreeNode top = new DefaultMutableTreeNode("Root");
        tree = new JTree(top);
        tree.addTreeSelectionListener(new TreeSelectionListener() {
            public void valueChanged(javax.swing.event.TreeSelectionEvent evt) {
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();
                textBox.setText(node.getUserObject().toString());
        }
        });

        JScrollPane scrollPane = new JScrollPane(tree);
        scrollPane.setHorizontalScrollBarPolicy(
            ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);

        // Add tree
        treePanel.add(scrollPane);
        panel.add(treePanel, BorderLayout.CENTER);

        // Add box and button to edit panel
        editPanel.add(textBox, BorderLayout.CENTER);
        editPanel.add(button, BorderLayout.SOUTH);

        // Add edit panel
        panel.add(editPanel, BorderLayout.SOUTH);

        // Add everything to the frame
        this.add(panel);
        this.setSize(300, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }
}

Answer 1

只是为了完整性:如果您仅通过模型 api 更新节点，它可能看起来稍微不那么难看

TreePath selected = tree.getSelectionPath();
tree.getModel().valueForPathChanged(selected, textBox.getText());