Java Swing JTree : how to change the focus on the last created node

Question

我的项目中有一个 Swing Jtree。我有一个 addNewItem 方法，它允许创建一个新节点。问题是如何在创建新节点后自动将焦点从当前元素更改为最后创建的节点，如图所示？

public void addNewItem(){
        DefaultMutableTreeNode node = ((DefaultMutableTreeNode)getTree().getLastSelectedPathComponent());
        if(node==null) return;
        Holder h_node   = (Holder) node.getUserObject();
        String key = h_node.getData().getClass().getSimpleName();
        BaseNodeAdapter adp = BaseNodeAdapter.of(key, h_node.getData());
        while(adp==null && node!=null){
            node = (DefaultMutableTreeNode) node.getParent();
            h_node   = (Holder) node.getUserObject();
            key = h_node.getData().getClass().getSimpleName();
            adp = BaseNodeAdapter.of(key, h_node.getData());
        }
        if(adp==null) return; // no adapter

        System.out.println("addNewItem: adapter "+adp.getClass().getSimpleName());

        String[] selectable = adp.getSelectable();
        if(selectable.length==0) return; // no selectable
        String strPath = Tools.getPath(node);
        String type = (String)JOptionPane.showInputDialog(this,L("Create_a_new_item_for")+" "+key+":",strPath,JOptionPane.QUESTION_MESSAGE,null,selectable,null);
        if(type!=null){
            int res = adp.addItem(type);
            System.out.println("add item : "+res);
            if(res==BaseNodeAdapter.FAILED) return; // nothing
            if(res==BaseNodeAdapter.PARENT) rebuildNode((DefaultMutableTreeNode) node.getParent());
            else rebuildNode(node);
        }

    }

Answer 1

类似于:

TreePath current = new TreePath(nodeYouJustCreated.getPath());
tree.setSelectionPath( current );

编辑:

只需单击按钮即可添加更多节点:

import java.awt.*;
import java.util.*;
import javax.swing.*;
import javax.swing.tree.*;

public class TreeInsertMRE extends JPanel
{
    private JTree tree;
    private Random random = new Random();
    private int tableNumber = 20;

    public TreeInsertMRE()
    {
        super(new BorderLayout());

        //Create the nodes.
        DefaultMutableTreeNode top = new DefaultMutableTreeNode("Database");
        getDatabases(top);

        tree = new JTree(top);
        JScrollPane scrollPane = new JScrollPane(tree);
        add(scrollPane);

        JButton button = new JButton("Add Table to Database 1");
        add(button, BorderLayout.PAGE_END);

        button.addActionListener(e ->
        {
            DefaultTreeModel model = (DefaultTreeModel)tree.getModel();
            DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
            DefaultMutableTreeNode child = (DefaultMutableTreeNode)model.getChild(root, 1);

            String tableText = "Table " + tableNumber++;
            DefaultMutableTreeNode tableNode = new DefaultMutableTreeNode( tableText );
            child.add(tableNode);
            model.reload(child);

            TreePath current = new TreePath(tableNode.getPath());
            tree.setSelectionPath( current );
        });
    }

    private void getDatabases(DefaultMutableTreeNode top)
    {
        for (int i = 0; i < 5; i++)
        {
            String databaseName = "Database" + i;
            DefaultMutableTreeNode databaseNode = new DefaultMutableTreeNode(databaseName);
            top.add(databaseNode);
            getTables(databaseName, databaseNode);
        }
    }

    private void getTables(String databaseName, DefaultMutableTreeNode databaseNode)
    {
        for (int i = 0; i < 5; i++)
        {
            String tableName = "Table" + i;
            DefaultMutableTreeNode tableNode = new DefaultMutableTreeNode(tableName);
            databaseNode.add(tableNode);
            getColumns(tableName, tableNode);
        }
    }

    private void getColumns(String tableName, DefaultMutableTreeNode tableNode)
    {
        for (int i = 0; i < 5; i++)
        {
            String columnName = "Column" + i;
            DefaultMutableTreeNode columnNode = new DefaultMutableTreeNode(columnName);
            tableNode.add(columnNode);
        }
    }

    private static void createAndShowGUI()
    {
        JFrame frame = new JFrame("TreeInsertMRE");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new TreeInsertMRE());
        frame.setSize(300, 300);
        frame.setVisible(true);
    }

    public static void main(String[] args)
    {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}