jtree 父亲节点未展开是可以点击Button添加节点（create(jtree tree,string name)),当展开后就不行了。

include<stdio.h>int main()

{ int N,r

long double sum=0

long double a,b

scanf("%d",&N)

for(r=0r<Nr++){

scanf("%lf%lf",&a,&b)

//先选中节点才能增加节点

import java.awt.*

import java.awt.event.*

import javax.swing.*

import javax.swing.event.*

import javax.swing.tree.*

public class TreeTest implements ActionListener,TreeModelListener{

JLabel label=null

JTree tree=null

DefaultTreeModel treeModel=null

String nodeName=null//原有节点名称

public TreeTest(){

JFrame f=new JFrame("TreeTest")

Container contentPane=f.getContentPane()

DefaultMutableTreeNode root=new DefaultMutableTreeNode("资源管理器")

tree=new JTree(root)

tree.setEditable(true)

tree.addMouseListener(new MouseHandle())

treeModel=(DefaultTreeModel)tree.getModel()

treeModel.addTreeModelListener(this)

JScrollPane scrollPane=new JScrollPane()

scrollPane.setViewportView(tree)

JPanel panel=new JPanel()

JButton b=new JButton("新增节点")

b.addActionListener(this)

panel.add(b)

b=new JButton("删除节点")

b.addActionListener(this)

panel.add(b)

b=new JButton("清除所有节点")

b.addActionListener(this)

panel.add(b)

label=new JLabel("Action")

contentPane.add(panel,BorderLayout.NORTH)

contentPane.add(scrollPane,BorderLayout.CENTER)

contentPane.add(label,BorderLayout.SOUTH)

f.pack()

f.setVisible(true)

f.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e){

System.exit(0)

}

})

}

//本方法运行新增、删除、清除所有节点的程序代码.

public void actionPerformed(ActionEvent ae){

if (ae.getActionCommand().equals("新增节点")){

DefaultMutableTreeNode parentNode=null

DefaultMutableTreeNode newNode=new DefaultMutableTreeNode("新节点")

newNode.setAllowsChildren(true)

TreePath parentPath=tree.getSelectionPath()

//取得新节点的父节点

parentNode=(DefaultMutableTreeNode)(parentPath.getLastPathComponent())

//由DefaultTreeModel的insertNodeInto（）方法增加新节点

treeModel.insertNodeInto(newNode,parentNode,parentNode.getChildCount())

//tree的scrollPathToVisible()方法在使Tree会自动展开文件夹以便显示所加入的新节点。若没加这行则加入的新节点

//会被 包在文件夹中，你必须自行展开文件夹才看得到。

tree.scrollPathToVisible(new TreePath(newNode.getPath()))

label.setText("新增节点成功")

}

if (ae.getActionCommand().equals("删除节点")){

TreePath treepath=tree.getSelectionPath()

if (treepath!=null){

//下面两行取得选取节点的父节点.

DefaultMutableTreeNode selectionNode=(DefaultMutableTreeNode)treepath.getLastPathComponent()

TreeNode parent=(TreeNode)selectionNode.getParent()

if (parent!=null) {

//由DefaultTreeModel的removeNodeFromParent()方法删除节点，包含它的子节点。

treeModel.removeNodeFromParent(selectionNode)

label.setText("删除节点成功")

}

}

}

if (ae.getActionCommand().equals("清除所有节点")){

//下面一行，由DefaultTreeModel的getRoot()方法取得根节点.

DefaultMutableTreeNode rootNode=(DefaultMutableTreeNode)treeModel.getRoot()

//下面一行删除所有子节点.

rootNode.removeAllChildren()

//删除完后务必运行DefaultTreeModel的reload() *** 作，整个Tree的节点才会真正被删除.

treeModel.reload()

label.setText("清除所有节点成功")

}

}

public void treeNodesChanged(TreeModelEvent e){

TreePath treePath=e.getTreePath()

DefaultMutableTreeNode node=(DefaultMutableTreeNode)treePath.getLastPathComponent()

try{

int[] index=e.getChildIndices()

node=(DefaultMutableTreeNode)node.getChildAt(index[0])

}catch(NullPointerException exc){}

label.setText(nodeName+"更改数据为:"+(String)node.getUserObject())

}

public void treeNodesInserted(TreeModelEvent e){

System.out.println("new node insered")

}

public void treeNodesRemoved(TreeModelEvent e){

System.out.println("node deleted")

}

public void treeStructureChanged(TreeModelEvent e){

System.out.println("Structrue changed")

}

public static void main(String[] args){

new TreeTest()

}

class MouseHandle extends MouseAdapter{

public void mousePressed(MouseEvent e){

try{

JTree tree=(JTree)e.getSource()

int rowLocation=tree.getRowForLocation(e.getX(),e.getY())

TreePath treepath=tree.getPathForRow(rowLocation)

TreeNode treenode=(TreeNode)treepath.getLastPathComponent()

nodeName=treenode.toString()

}catch(NullPointerException ne){}

}

}

}

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