从结构化为路径的字符串数组填充 JTree答案

【问题标题】：Populate JTree from String array Structured as Paths从结构化为路径的字符串数组填充 JTree
【发布时间】：2020-06-29 10:35:58
【问题描述】：

我的 Java 项目需要帮助。如何从模式化为路径的字符串数组动态填充我的 JTree？比如，字符串

paths[][]={{"Animals", "Birds","Non_flying" ,"Chicken"},
{"Animals","Birds","Non_flying","Ostrich"}, 
{"Animals","Birds","Flying","Eagle"},
{"Animals","Birds","Flying","Crow"},
{"Animals","Reptiles","Lizard"},
{"Plants"," Fruit Bearing","Fruits","Mango"},
{"Plants"," Fruit Bearing","Vegetable","Eggplant"},
{"Plants"," Non-fruit Bearing","Sunflower"}};

Like this 我尝试了下面的代码，但它没有合并相似的节点。一定是treeify()方法里面的条件：

import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;

public class TreeTest extends javax.swing.JFrame{
    static JTree tree; 
    public static void setTree(){
        String paths[][]={{"Animals", "Birds","Non_flying" ,"Chicken"},
                         {"Animals","Birds","Non_flying","Ostrich"},    
                         {"Animals","Birds","Flying","Eagle"},
                         {"Animals","Birds","Flying","Crow"},
                         {"Animals","Reptiles","Lizard"},
                         {"Plants"," Fruit Bearing","Fruits","Mango"},
                         {"Plants"," Fruit Bearing","Vegetable","Eggplant"}, 
                         {"Plants"," Non-fruit Bearing","Sunflower"}};
        tree = new JTree(treeify(paths)); 
    }

    public static <T> DefaultMutableTreeNode treeify(String[][] paths) {
        DefaultMutableTreeNode root = null;
        DefaultMutableTreeNode subRoot = null;
        for ( String[] parent : paths)
        for ( String value : parent){
            if (root == null) {
                root = new DefaultMutableTreeNode(value);
            } else if (subRoot == null){
                subRoot = new DefaultMutableTreeNode(value);
                root.add(subRoot);
            } else {
                DefaultMutableTreeNode child = new DefaultMutableTreeNode(value);
                subRoot.add(child);
                subRoot = child;
            }
        }
        return root; 
    }

    public static void main(String[] args) {
        TreeTest test = new TreeTest();
        setTree();
        test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        test.add(new JScrollPane(tree));
        test.setSize(500,400);
        test.setLocationRelativeTo(null);
        test.setVisible(true); 
    }
}

【问题讨论】：

您必须搜索您正在构建的模型才能知道新节点适合的位置。假设您正在尝试添加{"Animals", "Birds","Non_flying" ,"Chicken"}。从根作为您的“当前”节点开始，并寻找一个名为"Animals" 的子节点；如果你没有找到它，添加一个空的"Animals" 节点作为“当前”的子节点。现在，将找到或添加的 "Animals" 节点设为您的新“当前”节点，并在其子节点中查找 "Birds" 节点，必要时添加它，依此类推...
任何可以在这里给我代码的人。我是 JTree 的新手。花了 2 周时间解决问题，但没有任何效果。

标签： java swing jtree

【解决方案1】：

这是treeify() 的一个版本，它实现了我在评论中概述的策略。这不是有史以来最优雅的事情，但它完成了工作：

public static DefaultMutableTreeNode treeify(String[][] paths) {
    DefaultMutableTreeNode root = new DefaultMutableTreeNode();
    for ( String[] path : paths) {
        DefaultMutableTreeNode curr = root;
        for ( String value : path){
            DefaultMutableTreeNode next = null;
            Enumeration ce = curr.children();
            while (ce.hasMoreElements()){
                DefaultMutableTreeNode kid = 
                    (DefaultMutableTreeNode) ce.nextElement();
                if (((String)kid.getUserObject()).equals(value)){
                    next = kid;
                    break;
                }
            }
            if (next == null){
                next = new DefaultMutableTreeNode(value);
                curr.add(next);
            }
            curr = next;
        }
    }
    return root; 
}

【讨论】：