JTree是不是有问题?(在JTree中删除一个节点时)

Question

高手都到哪里去了?
我想只要用 Java开发的人都会遇到这个问题的?
怎么会没人回答???!!!

Answer 1

使用JTree默认的构造方法建立的JTree,上面的那段程序确实没有错,但是我自己建了一棵树:
    
   //Construct the User Tree root Node.
    DefaultMutableTreeNode root = new DefaultMutableTreeNode("权限管理");
    jTreeUser = new JTree(root);
    nodeGroup = new DefaultMutableTreeNode("用户组");
    root.add(nodeGroup);
    nodeRole = new DefaultMutableTreeNode("角色");
    root.add(nodeRole);     getAllGroupAndRole();  //一个函数,用来取用户组,用户和角色
    for(int i = 0;i < UserGroup.size();i++) {
        //添加用户组
        //Leaf是自己写的一个类
        Leaf leafGroup = (Leaf)UserGroup.get(i);
        DefaultMutableTreeNode childGroup = new DefaultMutableTreeNode  (leafGroup);
        nodeGroup.add(childGroup);
        //添加每个用户组下的用户
        for (int j =0;j<UserInGroup[i].length;j++){
          Leaf leafUser = (Leaf)UserInGroup[i][j];
          DefaultMutableTreeNode grandChild = new DefaultMutableTreeNode(leafUser);
          childGroup.add(grandChild);
        }
        //添加角色
        Leaf leafRole = (Leaf)Roles.get(i);
        DefaultMutableTreeNode childRole = new DefaultMutableTreeNode(leafRole);
        nodeRole.add(childRole);
    }按照这个方法建立的JTree,就会出现问题!如果那位高手感兴趣,告诉我E-mail,我把代码发过来!
多谢了!急啊!

Answer 2

这不是推荐的用法
用Model的
insertNodeInto方法
或
removeNodeFromParent方法

Answer 3

可是JTree.java中,JTree.getDefaultTreeModel中用的就是我上面的方法.另外,我删除节点时,用的就是你说的removeNodeFromParent方法.

Answer 4

wolfsquare,我把代码给你发过去了!
Thanks a lot!
我用的是JBuilder3.0.

Answer 5

在删除了节点后,我用了validate方法仍然没有效果!

Answer 6

不会吧?怎么又没有消息了?
这个问题该不是大家都没有遇到吧?
faint!

Answer 7

你可以用这种方法试一试：
model.reLoad();

Answer 8

这是我修改过后的代码:
package UserManage;import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import java.util.*;public class UserManageFrame extends JFrame
       implements ActionListener,MenuListener{
  private JPopupMenu popup;
  private MouseAdapter msAdapter;
  private JTree jTreeUser;
  private JTree jTreeTest;
  private static DefaultTreeModel model;
  private TreeSelectionModel selectionModel;
  private DefaultMutableTreeNode nodeChoosed; //记录当前被选中的节点的信息
  private DefaultMutableTreeNode nodeGroup;
  private DefaultMutableTreeNode nodeRole;
  private Vector UserGroup;                   //记录所有用户组的信息
  private Object[][] UserInGroup;             //记录用户组中所有用户
  private Vector Roles;                       //记录所有角色的信息
  private JMenuItem addGroup;
  private JMenuItem delGroup;
  private JMenuItem modifyGroup;
  private JMenuItem addUser;
  private JMenuItem delUser;
  private JMenuItem modifyUser;
  private JMenuItem addRole;
  private JMenuItem delRole;
  private JMenuItem modifyRole;
  private JMenuItem setRights;
  public UserManageFrame() {    setTitle("权限管理系统");
    setSize(400,300);
    addWindowListener(new WindowAdapter(){
      public void windowClosing(WindowEvent e){
        System.exit(0);
      }
    });
    //Construct the User Tree root Node.
    DefaultMutableTreeNode root = new DefaultMutableTreeNode("权限管理");
    jTreeUser = new JTree(root);
    nodeGroup = new DefaultMutableTreeNode("用户组");
    root.add(nodeGroup);
    nodeRole = new DefaultMutableTreeNode("角色");
    root.add(nodeRole);
    jTreeUser = new JTree(root);
    model = (DefaultTreeModel)jTreeUser.getModel();
    selectionModel = jTreeUser.getSelectionModel();
    selectionModel.setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
    getAllGroupAndRole();
    for(int i = 0;i < UserGroup.size();i++) {
        //添加用户组
        Leaf leafGroup = (Leaf)UserGroup.get(i);
        DefaultMutableTreeNode childGroup = new DefaultMutableTreeNode(leafGroup);
        nodeGroup.add(childGroup);
        //添加每个用户组下的用户
        for (int j =0;j<UserInGroup[i].length;j++){
          Leaf leafUser = (Leaf)UserInGroup[i][j];
          DefaultMutableTreeNode grandChild = new DefaultMutableTreeNode(leafUser);
          childGroup.add(grandChild);
        }
        //添加角色
        Leaf leafRole = (Leaf)Roles.get(i);
        DefaultMutableTreeNode childRole = new DefaultMutableTreeNode(leafRole);
        nodeRole.add(childRole);
    }    //Initialize the Popup Menu
    //按照这种方法建立的菜单不能设定禁用
    //popup = makePopupMenu(new Object[]{"添加新用户组","删除选中用户组","修改用户组属性",
    //                                   "添加新用户","删除用户","修改用户属性",
    //                                   "添加角色","删除角色","修改角色属性" ,
    //                                   null,"设置权限"},this);    popup = new JPopupMenu();
    addGroup = new JMenuItem("添加新用户组");
    delGroup = new JMenuItem("删除选中用户组");
    modifyGroup = new JMenuItem("修改用户组属性");
    addUser = new JMenuItem("添加新用户");
    delUser = new JMenuItem("删除用户");
    modifyUser = new JMenuItem("修改用户属性");
    addRole = new JMenuItem("添加角色");
    delRole = new JMenuItem("删除角色");
    modifyRole = new JMenuItem("修改角色属性");
    setRights = new JMenuItem("设置权限");    addGroup.addActionListener(this);
    delGroup.addActionListener(this);
    modifyGroup.addActionListener(this);
    addUser.addActionListener(this);
    delUser.addActionListener(this);
    modifyUser.addActionListener(this);
    addRole.addActionListener(this);
    delRole.addActionListener(this);
    modifyRole.addActionListener(this);
    setRights.addActionListener(this);    popup.add(addGroup);
    popup.add(delGroup);
    popup.add(modifyGroup);
    popup.add(addUser);
    popup.add(delUser);
    popup.add(modifyUser);
    popup.add(addRole);
    popup.add(delRole);
    popup.add(modifyRole);
    popup.addSeparator();
    popup.add(setRights);    //Set the Interface components.
    JSplitPane jSplitPane = new JSplitPane();
    JPanel jPanelLeft = new JPanel();
    JPanel jPanelRight = new JPanel();
    JScrollPane jScrollPaneLeft = new JScrollPane();
    JScrollPane jScrollPaneRight = new JScrollPane();    Container contentPane = getContentPane();
    GridBagLayout gbl1 = new GridBagLayout();
    contentPane.setLayout(gbl1);
    contentPane.add(jSplitPane,new GridBagConstraints(0,0,1,1,1.0,1.0,
                    GridBagConstraints.CENTER,GridBagConstraints.BOTH,
                    new Insets(10,10,10,10),70,-50));
    jSplitPane.add(jPanelLeft,jSplitPane.LEFT);
    jSplitPane.add(jPanelRight,jSplitPane.RIGHT);    jPanelLeft.setLayout(new BorderLayout());
    jPanelLeft.add(jScrollPaneLeft,BorderLayout.CENTER);    jPanelRight.setLayout(new BorderLayout());
    jPanelRight.add(jScrollPaneRight,BorderLayout.CENTER);    jScrollPaneLeft.getViewport().add(jTreeUser, null);    jScrollPaneRight.getViewport().add(jTreeTest,null);    //Pop up the Popup Menu
    jTreeUser.addMouseListener(new MouseAdapter(){
      public void mousePressed(MouseEvent evt){      }
      public void mouseReleased(MouseEvent evt){
          if(nodeChoosed==null)return;
          if (!nodeChoosed.isRoot()){
            if (evt.isPopupTrigger()){
               if (nodeChoosed==nodeGroup){
                 addGroup.setEnabled(true);
                 delGroup.setEnabled(false);
                 modifyGroup.setEnabled(false);
                 addUser.setEnabled(false);
                 delUser.setEnabled(false);
                 modifyUser.setEnabled(false);
                 addRole.setEnabled(false);
                 delRole.setEnabled(false);
                 modifyRole.setEnabled(false);
                 setRights.setEnabled(false);
               }
               else if (nodeChoosed==nodeRole){
                 addGroup.setEnabled(false);
                 delGroup.setEnabled(false);
                 modifyGroup.setEnabled(false);
                 addUser.setEnabled(false);
                 delUser.setEnabled(false);
                 modifyUser.setEnabled(false);
                 addRole.setEnabled(true);
                 delRole.setEnabled(false);
                 modifyRole.setEnabled(false);
                 setRights.setEnabled(false);
               }
               else if (nodeChoosed.getParent()==nodeGroup){
                 addGroup.setEnabled(false);
                 delGroup.setEnabled(true);
                 modifyGroup.setEnabled(true);
                 addUser.setEnabled(true);
                 delUser.setEnabled(false);
                 modifyUser.setEnabled(true);
                 addRole.setEnabled(false);
                 delRole.setEnabled(false);
                 modifyRole.setEnabled(false);
                 setRights.setEnabled(true);
               }
               else if (nodeChoosed.getParent().getParent()==nodeGroup){
                 addGroup.setEnabled(false);
                 delGroup.setEnabled(false);
                 modifyGroup.setEnabled(false);
                 addUser.setEnabled(false);
                 delUser.setEnabled(true);
                 modifyUser.setEnabled(true);
                 addRole.setEnabled(false);
                 delRole.setEnabled(false);
                 modifyRole.setEnabled(false);
                 setRights.setEnabled(true);
               }
               else if (nodeChoosed.getParent()==nodeRole){
                 addGroup.setEnabled(false);
                 delGroup.setEnabled(false);
                 modifyGroup.setEnabled(false);
                 addUser.setEnabled(false);
                 delUser.setEnabled(false);
                 modifyUser.setEnabled(false);
                 addRole.setEnabled(false);
                 delRole.setEnabled(true);
                 modifyRole.setEnabled(true);
                 setRights.setEnabled(true);
               }
              popup.show(evt.getComponent(),evt.getX(),evt.getY());
            }
          }
      }
    });    //TreeSelectionListener
    jTreeUser.addTreeSelectionListener(new TreeSelectionListener(){
      public void valueChanged(TreeSelectionEvent e){
        TreePath path = e.getNewLeadSelectionPath();
        if(path==null)return;
        nodeChoosed = (DefaultMutableTreeNode)path.getLastPathComponent();
        if(nodeChoosed==null)return;
        Leaf leaf = (Leaf)nodeChoosed.getUserObject();
        if(leaf==null)return;
        if(!(leaf instanceof Leaf))return; 
        String [] str = {leaf.groupOrRoleID,leaf.groupOrRoleName};
        JOptionPane.showMessageDialog(UserManageFrame.this,str[0]+"--"+str[1],
                                      "TreeSelected",JOptionPane.INFORMATION_MESSAGE);
       }
    });   model.addTreeModelListener(new TreeModelListener() {
public void treeNodesInserted(TreeModelEvent e) {
showInsertionOrRemoval(e, " added to ");
}
public void treeNodesRemoved(TreeModelEvent e) {
showInsertionOrRemoval(e, " removed from ");
}
private void showInsertionOrRemoval(TreeModelEvent e,
String s) {
Object[] parentPath = e.getPath();
int[] indexes = e.getChildIndices();
Object[] children = e.getChildren();
Object parent = parentPath[parentPath.length-1]; JOptionPane.showMessageDialog(UserManageFrame.this,
   "Node \"" + children[0].toString() +
   "\"" + s + parent.toString() +
   " at index " + indexes[0],
   "Node Added or Removed",
   JOptionPane.INFORMATION_MESSAGE);
}
public void treeNodesChanged(TreeModelEvent e) {}
public void treeStructureChanged(TreeModelEvent e) {}
});
  }  //Function to make Popup menu
  public static JPopupMenu makePopupMenu(Object[] items,Object target){
    JPopupMenu m= new JPopupMenu();
    for (int i=0;i<items.length;i++){
      if (items[i]==null)
        m.addSeparator();
      else
        m.add(makeMenuItem(items[i],target));
    }
    return m;
  }
  //Function to make menuItems
  public static JMenuItem makeMenuItem(Object item,Object target){
    JMenuItem r = null;
    if (item instanceof String)
      r = new JMenuItem((String)item);
    else if (item instanceof JMenuItem)
      r = (JMenuItem)item;
    else
      return null;
    if (target instanceof ActionListener)
      r.addActionListener((ActionListener)target);
    return r;
  }
  //Function actionPerformed
  public void actionPerformed(ActionEvent evt){
    if (evt.getSource() instanceof JMenuItem){
      String arg = evt.getActionCommand();
      if (arg.equals("添加新用户组")){
        JOptionPane.showMessageDialog(UserManageFrame.this,
        "Add new Group","Add",JOptionPane.INFORMATION_MESSAGE);
        String sgroupID = JOptionPane.showInputDialog(UserManageFrame.this,"请输入用户组id号",
        "New Group Node",JOptionPane.QUESTION_MESSAGE);
        String sgroupName = JOptionPane.showInputDialog(UserManageFrame.this,"请输入用户组名称",
        "New Group Node",JOptionPane.QUESTION_MESSAGE);
        Leaf leaf = new Leaf(sgroupID,sgroupName);
        DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(leaf);
        int index = nodeChoosed.getIndex(nodeChoosed)+1;
        model.insertNodeInto(newNode,nodeChoosed,index);
      }
      else if (arg.equals("删除选中用户组")){
        JOptionPane.showMessageDialog(UserManageFrame.this,
        "Delete Selected Group","Del",JOptionPane.INFORMATION_MESSAGE);
        TreePath path = selectionModel.getSelectionPath();
        DefaultMutableTreeNode node = (DefaultMutableTreeNode)path.getLastPathComponent();
        //model.removeNodeFromParent(node);
        node.removeFromParent();
        jTreeUser.updateUI();
      }
      else if (arg.equals("修改用户组属性")){      }
      else if (arg.equals("添加新用户")){
        JOptionPane.showMessageDialog(UserManageFrame.this,
                                      "Add new User","Add User",JOptionPane.INFORMATION_MESSAGE);
        String sgroupID = JOptionPane.showInputDialog(UserManageFrame.this,"请输入用户id号",
                                      "New User Node",JOptionPane.QUESTION_MESSAGE);
        String sgroupName = JOptionPane.showInputDialog(UserManageFrame.this,"请输入用户名称",
                                      "New User Node",JOptionPane.QUESTION_MESSAGE);
        Leaf leaf = new Leaf(sgroupID,sgroupName);
        MutableTreeNode newNode = new DefaultMutableTreeNode(leaf);
        int index = nodeChoosed.getIndex(nodeChoosed)+1;
        model.insertNodeInto(newNode,nodeChoosed,index);
      }
      else if (arg.equals("删除用户")){
        JOptionPane.showMessageDialog(UserManageFrame.this,
                                      "Delete Selected User","Del",JOptionPane.INFORMATION_MESSAGE);
        TreePath path = selectionModel.getSelectionPath();
        JOptionPane.showMessageDialog(UserManageFrame.this,
                                      path.toString(),"Del",JOptionPane.INFORMATION_MESSAGE);        MutableTreeNode node = (MutableTreeNode)path.getLastPathComponent();
        //model.removeNodeFromParent(node);
        node.removeFromParent();
        jTreeUser.updateUI();
      }
      else if (arg.equals("修改用户属性")){      }
      else if (arg.equals("添加角色")){      }
      else if (arg.equals("删除角色")){      }
      else if (arg.equals("修改角色属性")){      }
      else if (arg.equals("设置权限")){      }
    }
  }  public void menuSelected(MenuEvent evt){
    //JOptionPane.showMessageDialog(UserManageFrame.this,"OK","OK",JOptionPane.INFORMATION_MESSAGE);
    //if (nodeChoosed.getParent()==nodeGroup)
    //  addGroup.setEnabled(false);
  }
  public void menuDeselected(MenuEvent evt){  }
  public void menuCanceled(MenuEvent evt){  }  class Leaf {                      //记录所选用户组/角色的ID号和名称
    String groupOrRoleID;           //用户组/角色ID号
    String groupOrRoleName;         //用户组/角色名称
    public Leaf(String grID,String grName) {
      groupOrRoleID = grID;
      groupOrRoleName = grName;
    }
    public String toString() {
      return groupOrRoleName;
    }
  }  //获得所有用户组的信息,并将其存储在Vector--UserGroup和Roles中
  void getAllGroupAndRole() {
    int len = 10;
    UserGroup = new Vector(len,1);   //构建用户组空矢量
    Roles = new Vector(len,1);       //构建角色空矢量
    UserInGroup = new Object[len][]; //构建二维数组存放所有用户    for (int i =0;i<len;i++)
      UserInGroup[i] = new Object[i+1];    for(int i = 0;i < len;i ++ ){
      Leaf leafGroup = new Leaf("Group" + i,"用户组" + i);
      UserGroup.add(leafGroup);
      Leaf leafRole = new Leaf("Role"+ i,"角色"+ i);
      Roles.add(leafRole);
      for (int j = 0;j<UserInGroup[i].length;j++){
        Leaf leafUser = new Leaf("User"+i+j,"用户"+i+j);
        UserInGroup[i][j]=leafUser;
      }
    }
  }
}

Answer 9

wolfsquare!!!
谢谢!
你是只加了一句jTreeUser.updateUI()吗?
真是四两拨千金啊!
哎,这么个问题,我搞了n长时间都没搞定,好羡慕你的功力啊!
我把分数给你加上了!
再次表示感谢!

Answer 10

原来这里还有这么多变化!!wolfsquare还有点问题!当我在TreeSelection 中的valueChanged方法中,使用了nodeChoosed.getUserObject(),当我点击展开树时,后台会出现异常!如果不用它,就没有,为什么呢?        TreePath path = e.getNewLeadSelectionPath();
        if(path==null)return;
        nodeChoosed = (DefaultMutableTreeNode)path.getLastPathComponent();
        if(nodeChoosed==null)return;
        Leaf leaf = (Leaf)nodeChoosed.getUserObject();
        if(leaf==null)return;
        if(!(leaf instanceof Leaf))return;
        String [] str = {leaf.groupOrRoleID,leaf.groupOrRoleName};
        JOptionPane.showMessageDialog(UserManageFrame.this,str[0]+"--"+str[1],
                              "TreeSelected",JOptionPane.INFORMATION_MESSAGE);
错误如下:
Exception occurred during event dispatching:
java.lang.ClassCastException: java.lang.String
at UserManage.UserManageFrame$3.valueChanged(UserManageFrame.java:220)
at javax.swing.JTree.fireValueChanged(JTree.java:2053)
at javax.swing.JTree$TreeSelectionRedirector.valueChanged(JTree.java:2353)
at javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:583)
at javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:899)
at javax.swing.tree.DefaultTreeSelectionModel.setSelectionPaths(DefaultTreeSelectionModel.java:245)
at javax.swing.tree.DefaultTreeSelectionModel.setSelectionPath(DefaultTreeSelectionModel.java:140)
at javax.swing.JTree.setSelectionPath(JTree.java:977)
at javax.swing.plaf.basic.BasicTreeUI.selectPathForEvent(BasicTreeUI.java:2006)
at javax.swing.plaf.basic.BasicTreeUI$MouseHandler.mousePressed(BasicTreeUI.java:2549)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:220)
at java.awt.Component.processMouseEvent(Compiled Code)
at java.awt.Component.processEvent(Compiled Code)
at java.awt.Container.processEvent(Compiled Code)
at java.awt.Component.dispatchEventImpl(Compiled Code)
at java.awt.Container.dispatchEventImpl(Compiled Code)
at java.awt.Component.dispatchEvent(Compiled Code)
at java.awt.LightweightDispatcher.retargetMouseEvent(Compiled Code)
at java.awt.LightweightDispatcher.processMouseEvent(Compiled Code)
at java.awt.LightweightDispatcher.dispatchEvent(Compiled Code)
at java.awt.Container.dispatchEventImpl(Compiled Code)
at java.awt.Window.dispatchEventImpl(Compiled Code)
at java.awt.Component.dispatchEvent(Compiled Code)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:258)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:68)

Answer 11

这是你的节点的UserObject不是Leaf类,缺省是String.可能是因为组节点没有设置UserObject造成的.