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几天来，我一直在用头撞砖墙JTree！

我想创建一个JTree在运行时动态获取其内容的 mp3 标签。到目前为止一切顺利，除了我在填充 JTree 时非常头疼。经过大量的实验，我终于放弃并寻求帮助。我一直在使用我在下面创建的类来试验将子节点添加到JTree. 我遇到的问题在 try 块内，类型不兼容。我收到的错误是：

error: incompatible types: `TreeNode` cannot be converted to `MutableTreeNode`

treeModel.insertNodeInto需要MutableTreeNode它的第二个参数。我用来获取第二个参数的父节点的方法rootNode.getChildAt()返回TreeNode。

有没有办法解决？？？现在有没有人为什么getChildAt()返回一个TreeNode对象而不是DefaulMutableTreeNode，对象类型rootNode被初始化为？？？

package jtreeex;

import java.util.Enumeration;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeSelectionModel;

/**
 *
 * @author david
 */
public class JTreeEx implements Runnable
{

    public JTreeEx()
    {
        JFrame jfrm = new JFrame();  
        JPanel panel = new JPanel();
        JTree tree;

        DefaultMutableTreeNode rootNode;
        rootNode = new DefaultMutableTreeNode("Audio");
        DefaultTreeModel treeModel = new DefaultTreeModel(rootNode);
        treeModel.addTreeModelListener(new MyTreeModelListener());

        tree = new JTree(treeModel);
        tree.setEditable(true);
        tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
        tree.setShowsRootHandles(true);
        String [] anArray = {"Dogs", "Cats"};


        // Inserts new root nodes from anArray
        for(int i = 0; i < anArray.length; i++)
        {
            treeModel.insertNodeInto(new DefaultMutableTreeNode(anArray[i]), 
                    rootNode, rootNode.getChildCount());

        }

        // Get enumeration of children of rootNode
        Enumeration eNum = rootNode.children();

        try
        {
            while(eNum.hasMoreElements() == true)
            {
                treeModel.insertNodeInto(new DefaultMutableTreeNode("Toby"), 
                        rootNode.getChildAt(1), rootNode.getChildCount());
            }
        }
        catch (Exception e)
        {
            System.out.println("no enums left");
        }

        panel.add(tree);

        jfrm.add(panel);
        jfrm.setSize(400,200);
        jfrm.setVisible(true);
        jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here

        (new Thread(new JTreeEx())).start();
    }

    public void run()
    {

    }

}
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1 回答 1

1

treeModel.insertNodeInto 的第二个参数需要 MutableTreeNode。我用来获取第二个参数的父节点的方法，rootNode.getChildAt() 返回 TreeNode。

您正在构建树，并且您知道将 DefaultMutableTreeNodes 插入到树中，因此只需将 TreeNode 转换为 DefaultMutableTreeNode：

treeModel.insertNodeInto(new DefaultMutableTreeNode("Toby"), 
    (DefaultMutableTreeNode)rootNode.getChildAt(1), rootNode.getChildCount());
于 2014-06-19T14:48:03.353 回答