Java Swing JTree：如何將焦點更改在最后創建的節點上

Question

我的項目中有一個 Swing Jtree。 我有一個 addNewItem 方法，它允許創建一個新節點。 問題是如何在自動創建新節點后立即將焦點從當前元素更改為最后創建的節點，如圖所示？

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

就像是：

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

編輯：

只需單擊按鈕即可添加更多節點：

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();
            }
        });
    }
}