诚恳请教关于JTree的实时更新问题!(可以追加给分!急!!非常感谢) 想做实时更新的树形结构,但是遇到下次更新时候,上次展开节点不能不能保留的问题。这样刷新后的树就又复原了。请教各位是否有什么办法解决这个问题!!万分感谢! 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 to cuij7718:添加或者删除了节点后,重新画了一颗树,树的状态就是关闭的,也就是说树没有展开刚才展开的节点。to dulang200x:没有重建对象。有人说把原先打开的treepath保存起来,下次刷新的时候展开。谁用过这种办法吗?怎么用啊? 我们都在jtree上遇到问题了,帮你顶一下吧 谢谢帮忙顶的TX,只是感觉现在对JTree研究的比较透彻的人怎么越来越少了。好多天了,都还没有解决~~~ 更新模型中的数据后,只要用tree.updateUI()就可以刷新树,还会保留刷新前的展开状态。 添加不需要重画树就可以自动更新,删除需要重画树,不过重画还是算了吧,耗资源而且不能保持状态。如果确实需要刷新的就使用updateUI吧 用treeModel.nodeStructureChanged(node)也不会重绘整棵树。 package com.test;import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;import javax.swing.tree.*;public class test implements ActionListener,TreeModelListener{ JLabel label = null; JTree tree = null; DefaultTreeModel treeModel = null; String nodeName = null; //原有节点名称 public test() { JFrame f = new JFrame("TreeDemo"); 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); 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); } }); } 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(); parentNode = (DefaultMutableTreeNode) (parentPath.getLastPathComponent()); treeModel.insertNodeInto(newNode,parentNode,parentNode.getChildCount()); tree.scrollPathToVisible(new TreePath(newNode.getPath())); label.setText("新增节点成功"); } } 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 inserted"); } 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 test(); } 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){} } }} 好好看看这个例子。实在不明白查查API 升序函数 GUI高手请进来帮忙 java程序转成EXE能脱离JRE么 麻烦问一下谁能告诉我,java 连接oracle 的方法有几种,分别是什么? 有个问题不太明白,望高手解答。 关于uri的问题,请理解的同志指点 swing 的一个令人不思意的问题,不会SUN公司一个BUG吧(dialog不能控制大小)?---高手请进 请问下面这段代码是怎么输出的,为什么 我想给程序写进度条,大家给点意见 No buffer space available (maximum connections reached?): recv failed java main 有没有写正则表达式的高手
添加或者删除了节点后,重新画了一颗树,树的状态就是关闭的,也就是说树没有展开刚才展开的节点。to dulang200x:
没有重建对象。有人说把原先打开的treepath保存起来,下次刷新的时候展开。谁用过这种办法吗?怎么用啊?
package com.test;import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;public class test implements ActionListener,TreeModelListener
{
JLabel label = null;
JTree tree = null;
DefaultTreeModel treeModel = null;
String nodeName = null; //原有节点名称 public test()
{
JFrame f = new JFrame("TreeDemo");
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); 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);
}
}); } 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(); parentNode = (DefaultMutableTreeNode)
(parentPath.getLastPathComponent()); treeModel.insertNodeInto(newNode,parentNode,parentNode.getChildCount());
tree.scrollPathToVisible(new TreePath(newNode.getPath())); label.setText("新增节点成功");
} } 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 inserted");
}
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 test();
} 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){}
}
}
}