Java ArrayList中的JTree不显示节点
我有一个自定义数据结构,它基本上只是ArrayList中的一个命名ArrayList。类似于XML (删除了联合国的内塞卡里代码)Java ArrayList中的JTree不显示节点,java,swing,jtree,Java,Swing,Jtree,我有一个自定义数据结构,它基本上只是ArrayList中的一个命名ArrayList。类似于XML (删除了联合国的内塞卡里代码) 公共类元素扩展了ArrayList{ 私有字符串名称; 公共元素(字符串n){ name=n; } @凌驾 公共字符串toString(){ 返回名称; } } 我试图使用一个定制的TreeModel类在JTree中显示它。但是,JTree无法正确显示。分支末端仅显示一个节点,选择子节点时显示最后一个子节点,而取消选择时显示第一个子节点,但仍在分支末端 从广泛的
公共类元素扩展了ArrayList{
私有字符串名称;
公共元素(字符串n){
name=n;
}
@凌驾
公共字符串toString(){
返回名称;
}
}
我试图使用一个定制的TreeModel类在JTree中显示它。但是,JTree无法正确显示。分支末端仅显示一个节点,选择子节点时显示最后一个子节点,而取消选择时显示第一个子节点,但仍在分支末端
从广泛的反窃听中,我可以看到它读取所有子节点并正确计数,只是没有显示它们。我怀疑他们都被展示在彼此的上面,但不知道为什么或者怎么做
多谢你的好意
public class TestModel implements TreeModel{
Element data;
TestModel(){
data = new Element("data");
data.add(new Element("One"));
data.add(new Element("Two"));
data.add(new Element("Three"));
data.add(new Element("Four"));
data.add(new Element("Five"));
}
@Override
public Object getRoot() {
return data;
}
@Override
public Object getChild(Object parent, int index) {
if(parent instanceof Element){
Element p = (Element)parent;
Element child = p.get(index);
return child;
}
return null;
}
@Override
public int getChildCount(Object parent) {
if(parent instanceof Element){
Element e = (Element)parent;
return e.size();
}
return 0;
}
@Override
public int getIndexOfChild(Object parent, Object child) {
if(parent instanceof Element){
Element e = (Element)parent;
return e.indexOf(child);
}
return -1;
}
@Override
public boolean isLeaf(Object node) {
//List<? super ArrayList> d = (List<? super ArrayList>) node;
if(node instanceof Element){
Element e = (Element)node;
return e.isEmpty();
}
return true;
}
}
public类TestModel实现TreeModel{
元素数据;
TestModel(){
数据=新元素(“数据”);
数据。添加(新元素(“一”);
添加(新元素(“两”));
数据。添加(新元素(“三”);
添加(新元素(“四”));
数据。添加(新元素(“五”);
}
@凌驾
公共对象getRoot(){
返回数据;
}
@凌驾
公共对象getChild(对象父对象,int索引){
if(元素的父实例){
元素p=(元素)父元素;
元素子元素=p.get(索引);
返回儿童;
}
返回null;
}
@凌驾
public int getChildCount(对象父对象){
if(元素的父实例){
元素e=(元素)父元素;
返回e.size();
}
返回0;
}
@凌驾
public int getIndexOfChild(对象父对象、对象子对象){
if(元素的父实例){
元素e=(元素)父元素;
返回e.indexOf(儿童);
}
返回-1;
}
@凌驾
公共布尔isLeaf(对象节点){
//List问题在于如何使用元素
类并从ArrayList
扩展它。这归结为如何从ArrayList
计算hashcode
(或者更准确地说,AbstractList
)
hashcode
是基于ArrayList
中的元素来计算的,对于所有子元素0
,导致所有子元素hashcode
的1
,这导致列表查找和唯一标识元素出现问题
就我个人而言,我会创建一个节点
类,其中包含一个列表
成员,并提供额外的功能,可以使用树模型
或只使用
例如
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.MutableTreeNode;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
public class TestTree {
public static void main(String[] args) {
new TestTree();
}
public TestTree() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JTree tree = new JTree(new TestModel());
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new JScrollPane(tree));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestModel implements TreeModel {
Element data;
TestModel() {
data = new Element("data");
data.add(new Element("One"));
data.add(new Element("Two"));
data.add(new Element("Three"));
data.add(new Element("Four"));
data.add(new Element("Five"));
}
@Override
public Object getRoot() {
return data;
}
@Override
public Object getChild(Object parent, int index) {
System.out.println("GetChild from " + parent + " @ " + index);
if (parent instanceof Element) {
Element p = (Element) parent;
Object child = p.getChildAt(index);
System.out.println("child = " + child);
return child;
}
return null;
}
@Override
public int getChildCount(Object parent) {
if (parent instanceof Element) {
Element e = (Element) parent;
System.out.println("childCount = " + parent + "; " + e.getChildCount());
return e.getChildCount();
}
return 0;
}
@Override
public int getIndexOfChild(Object parent, Object child) {
if (parent instanceof Element && child instanceof Element) {
Element e = (Element) parent;
System.out.println("indexOf " + child + " in " + parent + " is " + e.getIndex((Element)child));
return e.getIndex((Element)child);
}
return -1;
}
@Override
public boolean isLeaf(Object node) {
//List<? super ArrayList> d = (List<? super ArrayList>) node;
if (node instanceof Element) {
Element e = (Element) node;
System.out.println("isLeaf " + e + "; " + (e.getChildCount() == 0));
return e.getChildCount() == 0;
}
return true;
}
@Override
public void valueForPathChanged(TreePath path, Object newValue) {
}
@Override
public void addTreeModelListener(TreeModelListener l) {
}
@Override
public void removeTreeModelListener(TreeModelListener l) {
}
}
public static class Element implements TreeNode {
private List<Element> nodes;
private Element parent;
private String name;
public Element(String n) {
nodes = new ArrayList<>(25);
name = n;
}
@Override
public String toString() {
return name;
}
protected void setParent(Element parent) {
this.parent = parent;
}
public void add(Element node) {
node.setParent(this);
nodes.add(node);
}
public void remove(Element node) {
node.setParent(null);
nodes.remove(node);
}
@Override
public TreeNode getChildAt(int childIndex) {
return nodes.get(childIndex);
}
@Override
public int getChildCount() {
return nodes.size();
}
@Override
public TreeNode getParent() {
return parent;
}
@Override
public int getIndex(TreeNode node) {
return nodes.indexOf(node);
}
@Override
public boolean getAllowsChildren() {
return true;
}
@Override
public boolean isLeaf() {
return nodes.isEmpty();
}
@Override
public Enumeration children() {
return Collections.enumeration(nodes);
}
}
}
导入java.awt.BorderLayout;
导入java.awt.EventQueue;
导入java.util.ArrayList;
导入java.util.Collections;
导入java.util.Enumeration;
导入java.util.List;
导入javax.swing.JFrame;
导入javax.swing.JScrollPane;
导入javax.swing.JTree;
导入javax.swing.UIManager;
导入javax.swing.UnsupportedLookAndFeelException;
导入javax.swing.event.TreeModelListener;
导入javax.swing.tree.DefaultMutableTreeNode;
导入javax.swing.tree.MutableTreeNode;
导入javax.swing.tree.TreeModel;
导入javax.swing.tree.TreeNode;
导入javax.swing.tree.TreePath;
公共类测试树{
公共静态void main(字符串[]args){
新的TestTree();
}
公共测试树(){
invokeLater(新的Runnable(){
@凌驾
公开募捐{
试一试{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}catch(ClassNotFoundException |实例化Exception | IllegalacessException |不支持ookandfeelException ex){
}
JTree-tree=newjtree(newtestmodel());
JFrame=新JFrame(“测试”);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(新的BorderLayout());
frame.add(新的JScrollPane(树));
frame.pack();
frame.setLocationRelativeTo(空);
frame.setVisible(true);
}
});
}
公共静态类TestModel实现TreeModel{
元素数据;
TestModel(){
数据=新元素(“数据”);
数据。添加(新元素(“一”);
添加(新元素(“两”));
数据。添加(新元素(“三”);
添加(新元素(“四”));
数据。添加(新元素(“五”);
}
@凌驾
公共对象getRoot(){
返回数据;
}
@凌驾
公共对象getChild(对象父对象,int索引){
System.out.println(“GetChild from”+parent+“@”+index);
if(元素的父实例){
元素p=(元素)父元素;
对象子对象=p.getChildAt(索引);
System.out.println(“child=“+child”);
返回儿童;
}
返回null;
}
@凌驾
public int getChildCount(对象父对象){
if(元素的父实例){
元素e=(元素)父元素;
System.out.println(“childCount=“+parent+”;“+e.getChildCount());
返回e.getChildCount();
}
返回0;
}
@凌驾
public int getIndexOfChild(对象父对象、对象子对象){
if(元素的父实例和元素的子实例){
元素e=(元素)父元素;
System.out.println(“inde
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.MutableTreeNode;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
public class TestTree {
public static void main(String[] args) {
new TestTree();
}
public TestTree() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JTree tree = new JTree(new TestModel());
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new JScrollPane(tree));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestModel implements TreeModel {
Element data;
TestModel() {
data = new Element("data");
data.add(new Element("One"));
data.add(new Element("Two"));
data.add(new Element("Three"));
data.add(new Element("Four"));
data.add(new Element("Five"));
}
@Override
public Object getRoot() {
return data;
}
@Override
public Object getChild(Object parent, int index) {
System.out.println("GetChild from " + parent + " @ " + index);
if (parent instanceof Element) {
Element p = (Element) parent;
Object child = p.getChildAt(index);
System.out.println("child = " + child);
return child;
}
return null;
}
@Override
public int getChildCount(Object parent) {
if (parent instanceof Element) {
Element e = (Element) parent;
System.out.println("childCount = " + parent + "; " + e.getChildCount());
return e.getChildCount();
}
return 0;
}
@Override
public int getIndexOfChild(Object parent, Object child) {
if (parent instanceof Element && child instanceof Element) {
Element e = (Element) parent;
System.out.println("indexOf " + child + " in " + parent + " is " + e.getIndex((Element)child));
return e.getIndex((Element)child);
}
return -1;
}
@Override
public boolean isLeaf(Object node) {
//List<? super ArrayList> d = (List<? super ArrayList>) node;
if (node instanceof Element) {
Element e = (Element) node;
System.out.println("isLeaf " + e + "; " + (e.getChildCount() == 0));
return e.getChildCount() == 0;
}
return true;
}
@Override
public void valueForPathChanged(TreePath path, Object newValue) {
}
@Override
public void addTreeModelListener(TreeModelListener l) {
}
@Override
public void removeTreeModelListener(TreeModelListener l) {
}
}
public static class Element implements TreeNode {
private List<Element> nodes;
private Element parent;
private String name;
public Element(String n) {
nodes = new ArrayList<>(25);
name = n;
}
@Override
public String toString() {
return name;
}
protected void setParent(Element parent) {
this.parent = parent;
}
public void add(Element node) {
node.setParent(this);
nodes.add(node);
}
public void remove(Element node) {
node.setParent(null);
nodes.remove(node);
}
@Override
public TreeNode getChildAt(int childIndex) {
return nodes.get(childIndex);
}
@Override
public int getChildCount() {
return nodes.size();
}
@Override
public TreeNode getParent() {
return parent;
}
@Override
public int getIndex(TreeNode node) {
return nodes.indexOf(node);
}
@Override
public boolean getAllowsChildren() {
return true;
}
@Override
public boolean isLeaf() {
return nodes.isEmpty();
}
@Override
public Enumeration children() {
return Collections.enumeration(nodes);
}
}
}