树(Tree)的使用与介绍

使用JTree组件：
   java.lang.Object
     --java.awt.Component
      --java.awt.Container
       --javax.swing.JComponent
        --javax.swing.JTree
JTree构造函数:
JTree():建立一棵系统默认的树。
JTree(Hashtable value):利用Hashtable建立树，不显示root node(根节点).
JTree(Object[] value):利用Object Array建立树，不显示root node.
JTree(TreeModel newModel):利用TreeModel建立树。
JTree(TreeNode root):利用TreeNode建立树。
JTree(TreeNode root,boolean asksAllowsChildren):利用TreeNode建立树，并决定是否允许子节点的存在.
JTree(Vector value):利用Vector建立树，不显示root node.

范例:
InitalTree.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class InitalTree{
  public InitalTree(){
  JFrame f=new JFrame("TreeDemo");
  Container contentPane=f.getContentPane();
 
  JTree tree=new JTree();
  JScrollPane scrollPane=new JScrollPane();
  scrollPane.setViewportView(tree);
 
  contentPane.add(scrollPane);
  f.pack();
  f.setVisible(true);
  f.addWindowListener(new WindowAdapter(){
  public void windowClosing(WindowEvent e){
     System.exit(0);
  }
  });
  }
  public static void main(String[] args){
  new InitalTree();
  }
}

10-2:以Hashtable构造JTree:
   上面的例子对我们并没有裨的帮助，因为各个节点的数据均是java的默认值，而非我们自己设置的。因此我们需利用其他JTree
构造函数来输入我们想要的节点数据。以下范例我们以Hashtable当作JTree的数据输入:
范例：TreeDemo1.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class TreeDemo1{
  public TreeDemo1(){
    JFrame f=new JFrame("TreeDemo1");
    Container contentPane=f.getContentPane();
   
    String[] s1={"公司文件","个人信件","私人文件"};
    String[] s2={"本机磁盘(C:)","本机磁盘(D:)","本机磁盘(E:)"};
    String[] s3={"奇摩站","职棒消息","网络书店"};
   
    Hashtable hashtable1=new Hashtable();
    Hashtable hashtable2=new Hashtable();
    hashtable1.put("我的公文包",s1);
    hashtable1.put("我的电脑",s2);
    hashtable1.put("收藏夹",hashtable2);
    hashtable2.put("网站列表",s3);
   
    Font font = new Font("Dialog", Font.PLAIN, 12);
    Enumeration keys = UIManager.getLookAndFeelDefaults().keys();
   /**定义widnows界面**/
    while (keys.hasMoreElements()) {
         Object key = keys.nextElement();
         if (UIManager.get(key) instanceof Font) {
             UIManager.put(key, font);
         }
   }
   try{
      UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); 
   }catch(Exception el){
      System.exit(0); 
   }
   /**定义widnows界面**/
    JTree tree=new JTree(hashtable1);
    JScrollPane scrollPane=new JScrollPane();
    scrollPane.setViewportView(tree);
  contentPane.add(scrollPane);
  f.pack();
  f.setVisible(true);
  f.addWindowListener(new WindowAdapter(){
  public void windowClosing(WindowEvent e){
     System.exit(0);
  }
  });
  }
  public static void main(String[] args){
  new TreeDemo1();
  }
}

纯XP界面的设置：

10-3:以TreeNode构造JTree:
   JTree上的每一个节点就代表一个TreeNode对象，TreeNode本身是一个Interface,里面定义了7个有关节点的方法，例如判断是否
为树叶节点、有几个子节点(getChildCount())、父节点为何(getparent())等等、这些方法的定义你可以在javax.swing.tree的
package中找到，读者可自行查阅java api文件。在实际的应用上，一般我们不会直接实作此界面，而是采用java所提供的
DefaultMutableTreeMode类，此类是实作MutableTreeNode界面而来，并提供了其他许多实用的方法。MutableTreeNode本身也是一
个Interface,且继承了TreeNode界面此类主要是定义一些节点的处理方式，例如新增节点(insert())、删除节点(remove())、设置
节点(setUserObject())等。整个关系如下图:
    TreeNode----extends--->MutableTreeNode---implements---DefaultMutableTreeNode

  接下来我们来看如何利DefaultMutableTreeNode来建立JTree,我们先来看DefaultMutableTreeNode的构造函数:

DefaultMutableTreeNode构造函数:
DefaultMutableTreeNode():建立空的DefaultMutableTreeNode对象。
DefaultMutableTreeNode(Object userObject):建立DefaultMutableTreeNode对象，节点为userObject对象。
DefaultMutableTreeNode(Object userObject,Boolean allowsChildren):建立DefaultMutableTreeNode对象，节点为userObject对
                                象并决定此节点是否允许具有子节点。
  以下为利用DefaultMutableTreeNode建立JTree的范例:TreeDemo2.java
    此程序"资源管理器"为此棵树的根节点.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
public class TreeDemo2{
  public TreeDemo2(){
    JFrame f=new JFrame("TreeDemo2");
    Container contentPane=f.getContentPane();
   
    DefaultMutableTreeNode root=new DefaultMutableTreeNode("资源管理器");
    DefaultMutableTreeNode node1=new DefaultMutableTreeNode("我的公文包");
    DefaultMutableTreeNode node2=new DefaultMutableTreeNode("我的电脑");
    DefaultMutableTreeNode node3=new DefaultMutableTreeNode("收藏夹");
    DefaultMutableTreeNode node4=new DefaultMutableTreeNode("Readme");
    root.add(node1);
    root.add(node2);
    root.add(node3);
    root.add(node4);
   
    DefaultMutableTreeNode leafnode=new DefaultMutableTreeNode("公司文件");
    node1.add(leafnode);
    leafnode=new DefaultMutableTreeNode("私人文件");
    node1.add(leafnode);
    leafnode=new DefaultMutableTreeNode("个人信件");
   
    leafnode=new DefaultMutableTreeNode("本机磁盘(C:)");
    node2.add(leafnode);
    leafnode=new DefaultMutableTreeNode("本机磁盘(D:)");
    node2.add(leafnode);
    leafnode=new DefaultMutableTreeNode("本机磁盘(E:)");
    node2.add(leafnode);
   
    DefaultMutableTreeNode node31=new DefaultMutableTreeNode("网站列表");
    node3.add(node31);
   
    leafnode=new DefaultMutableTreeNode("奇摩站");
    node31.add(leafnode);
    leafnode=new DefaultMutableTreeNode("职棒消息");
    node31.add(leafnode);
    leafnode=new DefaultMutableTreeNode("网络书店");
    node31.add(leafnode);
   
    JTree tree=new JTree(root);
    JScrollPane scrollPane=new JScrollPane();
    scrollPane.setViewportView(tree);
   
    contentPane.add(scrollPane);
  f.pack();
  f.setVisible(true);
  f.addWindowListener(new WindowAdapter(){
  public void windowClosing(WindowEvent e){
     System.exit(0);
  }
  });
  }
  public static void main(String[] args){
  new TreeDemo2();
  } 
}

10-4:以TreeModel构造JTree.
   除了以节点的观念(TreeNode)建立树之外，你可以用data model的模式建立树。树的data model称为TreeModel,用此模式的好处
是可以触发相关的树事件，来处理树可能产生的一些变动。TreeModel是一个interface,里面定义了8种方法;如果你是一个喜欢自己
动手做的人，或是你想显示的数据格式很复杂，你可以考虑直接实作TreeModel界面中所定义的方法来构造出JTree.TreeModel界面
的方法如下所示:
TreeModel方法:
void      addTreeModelListener(TreeModelListener l):增加一个TreeModelListener来监控TreeModelEvent事件。
Object    getChild(Object parent,int index):返回子节点。
int       getChildCount(Object parent):返回子节点数量.
int       getIndexOfChild(Object parent,Object child):返回子节点的索引值。
Object    getRoot():返回根节点。
boolean   isLeaf(Object node):判断是否为树叶节点。
void      removeTreeModelListener(TreeModelListener l):删除TreeModelListener。
void      valueForPathChanged(TreePath path,Object newValue):当用户改变Tree上的值时如何应对。

   你可以实作出这8种方法，然后构造出自己想要的JTree,不过在大部份的情况下我们通常不会这样做，毕竟要实作出这8种方法不
是件很轻松的事，而且java本身也提供了一个默认模式，叫做DefaultTreeModel,这个类已经实作了TreeModel界面，也另外提供许
多实用的方法。利用这个默认模式，我们便能很方便的构造出JTree出来了。下面为DefaultTreeModel的构造函数与范例:
DefaultTreeModel构造函数:
DefaultTreeModel(TreeNode root):建立DefaultTreeModel对象，并定出根节点。
DefaultTreeModel(TreeNode root,Boolean asksAllowsChildren):建立具有根节点的DefaultTreeModel对象，并决定此节点是否允
                       许具有子节点。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import com.incors.plaf.alloy.*;//组件的下载网址http://www.incors.com/lookandfeel/
/*将alloy.jar放在c:\j2sdk1.4.0\jre\lib\ext\目录下.
*/
public class TreeDemo3
{
    public TreeDemo3()
    {
        JFrame f = new JFrame("TreeDemo");
        Container contentPane = f.getContentPane();
       
       
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("资源管理器");
        DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("我的公文包");
        DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("我的电脑");
        DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("收藏夹");
        DefaultMutableTreeNode node4 = new DefaultMutableTreeNode("Readme");
       
        DefaultTreeModel treeModel = new DefaultTreeModel(root);

        /*DefaultTreeModel类所提供的insertNodeInto()方法加入节点到父节点的数量.
         *利用DefaultMutableTreeNode类所提供的getChildCount()方法取得目前子节点的数量.
         */
        treeModel.insertNodeInto(node1, root, root.getChildCount());
        treeModel.insertNodeInto(node2, root, root.getChildCount());
        treeModel.insertNodeInto(node3, root, root.getChildCount());
        treeModel.insertNodeInto(node4, root, root.getChildCount());
       
        DefaultMutableTreeNode leafnode = new
                DefaultMutableTreeNode("公司文件");

        //DefaultTreeModel类所提供的insertNodeInto()方法加入节点到父节点的数量.
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("个人信件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("私人文件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
       
        leafnode = new DefaultMutableTreeNode("本机磁盘(C:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(D:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(E:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
       
        DefaultMutableTreeNode node31 = new DefaultMutableTreeNode("网站列表");
        treeModel.insertNodeInto(node31, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("奇摩站");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("职棒消息");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("网络书店");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        try {
           LookAndFeel alloyLnF = new AlloyLookAndFeel();   
           UIManager.setLookAndFeel(alloyLnF);
        } catch (UnsupportedLookAndFeelException ex) {
        // You may handle the exception here
        }
         // this line needs to be implemented in order to make JWS work properly
          UIManager.getLookAndFeelDefaults().put("ClassLoader", getClass().getClassLoader());
       
        //以TreeModel建立JTree。
        JTree tree = new JTree(treeModel);
        /*改变JTree的外观**/
          tree.putClientProperty("JTree.lineStyle","Horizontal");
        /*改变JTree的外观**/
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setViewportView(tree);
       
        contentPane.add(scrollPane);
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

    }

    public static void main(String args[]) {
   
        new TreeDemo3();
    }
}
10-5:改变JTree的外观:
你可以使用JComponent所提供的putClientProperty(Object key,Object value)方法来设置java默认的JTree外观，设置方式共有
3种:
1.tree.putClientProperty("JTree.lineStyle","None"):java默认值。
2.tree.putClientProperty("JTree.lineStyle","Horizontal"):使JTree的文件夹间具有水平分隔线。
3.tree.putClientProperty("JTree.lineStyle","Angled"):使JTree具有类似Windows文件管理器的直角连接线。
  具体怎样做，可看上例.

10-6:更换JTree节点图案:
  JTree利用TreeCellRenderer界面来运行绘制节点的工作，同样的，你不需要直接支实作这个界面所定义的方法，因为java本身提
供一个已经实作好的类来给我们使用，此类就是DefaultTreeCellRenderer,你可以在javax.swing.tree package中找到此类所提供
的方法。下面为使用DefaultTreeCellRenderer更改节点图案的一个例子:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import com.incors.plaf.alloy.*;

public class TreeDemo4{
   public TreeDemo4(){
     JFrame f=new JFrame("TreeDemo");
     Container contentPane=f.getContentPane();
    
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("资源管理器");
        DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("我的公文包");
        DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("我的电脑");
        DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("收藏夹");
        DefaultMutableTreeNode node4 = new DefaultMutableTreeNode("Readme");
        DefaultTreeModel treeModel = new DefaultTreeModel(root);
        treeModel.insertNodeInto(node1, root, root.getChildCount());
        treeModel.insertNodeInto(node2, root, root.getChildCount());
        treeModel.insertNodeInto(node3, root, root.getChildCount());
        treeModel.insertNodeInto(node4, root, root.getChildCount());
       
        DefaultMutableTreeNode leafnode = new
                DefaultMutableTreeNode("公司文件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("个人信件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("私人文件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
       
        leafnode = new DefaultMutableTreeNode("本机磁盘(C:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(D:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(E:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
       
        DefaultMutableTreeNode node31 = new DefaultMutableTreeNode("网站列表");
        treeModel.insertNodeInto(node31, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("奇摩站");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("职棒消息");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("网络书店");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        try {
           LookAndFeel alloyLnF = new AlloyLookAndFeel();   
           UIManager.setLookAndFeel(alloyLnF);
        } catch (UnsupportedLookAndFeelException ex) {
        // You may handle the exception here
        }
         // this line needs to be implemented in order to make JWS work properly
          UIManager.getLookAndFeelDefaults().put("ClassLoader", getClass().getClassLoader());

        JTree tree = new JTree(treeModel);
        tree.setRowHeight(20);
        DefaultTreeCellRenderer cellRenderer=(DefaultTreeCellRenderer)tree.getCellRenderer();
        cellRenderer.setLeafIcon(new ImageIcon("..\\icons\\leaf.gif"));
        cellRenderer.setOpenIcon(new ImageIcon("..\\icons\\open.gif"));
        cellRenderer.setClosedIcon(new ImageIcon("..\\icons\\close.gif"));
       
        cellRenderer.setFont(new Font("宋体",Font.PLAIN,12));//设置字体.
        cellRenderer.setBackgroundNonSelectionColor(Color.white);
        cellRenderer.setBackgroundSelectionColor(Color.yellow);
        cellRenderer.setBorderSelectionColor(Color.red);
        /*设置选时或不选时，文字的变化颜色
         */
        cellRenderer.setTextNonSelectionColor(Color.black);
        cellRenderer.setTextSelectionColor(Color.blue);
       
        JScrollPane scrollPane=new JScrollPane();
        scrollPane.setViewportView(tree);
       
        contentPane.add(scrollPane);
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

    }

    public static void main(String args[]) {
   
        new TreeDemo4();
    }
}
Window Xp界面:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
import com.incors.plaf.alloy.*;
public class TreeDemo3
{
    public TreeDemo3()
    {
       //设置成Alloy界面样式
        try {
           AlloyLookAndFeel.setProperty("alloy.isLookAndFeelFrameDecoration", "true");
           LookAndFeel alloyLnF = new AlloyLookAndFeel(); 
           JFrame.setDefaultLookAndFeelDecorated(true); 
           UIManager.setLookAndFeel(alloyLnF);
        } catch (UnsupportedLookAndFeelException ex) {
        // You may handle the exception here
        }
         // this line needs to be implemented in order to make JWS work properly
        UIManager.getLookAndFeelDefaults().put("ClassLoader", getClass().getClassLoader());
         
         //JDialog.setDefaultLookAndFeelDecorated(true);
        JFrame f = new JFrame("firstTree");
      
        Container contentPane = f.getContentPane();
       // if (contentPane instanceof JComponent) {
        //   ((JComponent) contentPane).setMinimumSize(new Dimension(100, 100));
        //}
       // Container contentPane = f.getContentPane();
       
       
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("资源管理器");
        DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("我的公文包");
        DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("我的电脑");
        DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("收藏夹");
        DefaultMutableTreeNode node4 = new DefaultMutableTreeNode("Readme");
       
        DefaultTreeModel treeModel = new DefaultTreeModel(root);
        treeModel.insertNodeInto(node1, root, root.getChildCount());
        treeModel.insertNodeInto(node2, root, root.getChildCount());
        treeModel.insertNodeInto(node3, root, root.getChildCount());
        treeModel.insertNodeInto(node4, root, root.getChildCount());
       
        DefaultMutableTreeNode leafnode = new
                DefaultMutableTreeNode("公司文件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("个人信件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
        leafnode = new DefaultMutableTreeNode("私人文件");
        treeModel.insertNodeInto(leafnode, node1, node1.getChildCount());
       
        leafnode = new DefaultMutableTreeNode("本机磁盘(C:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(D:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
        leafnode = new DefaultMutableTreeNode("本机磁盘(E:)");
        treeModel.insertNodeInto(leafnode, node2, node2.getChildCount());
       
        DefaultMutableTreeNode node31 = new DefaultMutableTreeNode("网站列表");
        treeModel.insertNodeInto(node31, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("奇摩站");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("职棒消息");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());
        leafnode = new DefaultMutableTreeNode("网络书店");
        treeModel.insertNodeInto(leafnode, node3, node3.getChildCount());

        JTree tree = new JTree(treeModel);
        /*改变JTree的外观**/
        //  tree.putClientProperty("JTree.lineStyle","Horizontal");
        /*改变JTree的外观**/
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setViewportView(tree);
       
        contentPane.add(scrollPane);
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

    }

    public static void main(String args[]) {
   
        new TreeDemo3();
    }
}


10-7:JTree的事件处理模式:
    在此节中，我们将详细介绍JTree两个常用的事件与处理，分别是TreeModeEvent与TreeSelectionEvent.
10-7-1:处理TreeModeEvent事件：
  当树的结构上有任何改变时，例如节点值改变了、新增节点、删除节点等，都会TreeModelEvent事件，要处理这样的事件必须实
作TreeModelListener界面，此界面定义了4个方法，如下所示:
TreeModelListener方法:
Void              treeNodesChanged(TreeModelEvent e):当节点改变时系统就会云调用这个方法。
Void              treeNodesInserted(TreeModelEvent e):当新增节时系统就会去调用这个方法。
Void              treeNodesRemoved(TreeModeEvent e):当删除节点时系统就会去调用这个方法。
Void              treeStructureChanged(TreeModelEvent e):当树结构改变时系统就会去调用这个方法。

  TreeModelEvent类本身提供了5个方法，帮我们取得事件的信息，如下所示:

TreeModelEvent方法：
int[]                getChildIndices():返回子节点群的索引值。
Object[]             getChildren():返回子节点群.
Object[]             getPath():返回Tree中一条path上(从root nod到leaf node)的节点。
TreePath             getTreePath():取得目前位置的Tree Path.
String               toString()：取得蝗字符串表示法.
 
    由TreeModelEvent的getTreePath()方法就可以得到TreePath对象，此对象就能够让我们知道用户目前正选哪一个节点，
TreePath类最常用的方法为：
     public  Object getLastPathComponent():取得最深（内）层的节点。
     public int    getPathCount():取得此path上共有几个节点.
    我们来看下面这个例子，用户可以在Tree上编辑节点，按下[Enter]键后就可以改变原有的值，并将改变的值显示在下面的
JLabel中:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import com.incors.plaf.alloy.*;
import com.incors.plaf.alloy.themes.bedouin.*;

public class TreeDemo5 implements TreeModelListener
{
    JLabel label = null;
    String nodeName = null; //原有节点名称
   
    public TreeDemo5()
    {
        try {
        AlloyLookAndFeel.setProperty("alloy.isLookAndFeelFrameDecoration", "true");
        AlloyTheme theme = new BedouinTheme();//设置界面的外观，手册中共有5种样式
        LookAndFeel alloyLnF = new AlloyLookAndFeel(theme);
            UIManager.setLookAndFeel(alloyLnF);
        } catch (UnsupportedLookAndFeelException ex) {
        // You may handle the exception here
        }
         // this line needs to be implemented in order to make JWS work properly
        UIManager.getLookAndFeelDefaults().put("ClassLoader", getClass().getClassLoader());
        JFrame f = new JFrame("TreeDemo");
        Container contentPane = f.getContentPane();
       
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("资源管理器");
        DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("文件夹");
        DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("我的电脑");
        DefaultMutableTreeNode node3 = new DefaultMutableTreeNode("收藏夹");
        DefaultMutableTreeNode node4 = new DefaultMutableTreeNode("Readme");
        root.add(node1);
        root.add(node2);
        root.add(node3);
        root.add(node4);
       
        DefaultMutableTreeNode leafnode = new DefaultMutableTreeNode("公司文件");
        node1.add(leafnode);
        leafnode = new DefaultMutableTreeNode("个人信件");
        node1.add(leafnode);
        leafnode = new DefaultMutableTreeNode("私人文件");
        node1.add(leafnode);
       
        leafnode = new DefaultMutableTreeNode("本机磁盘(C:)");
        node2.add(leafnode);
        leafnode = new DefaultMutableTreeNode("本机磁盘(D:)");
        node2.add(leafnode);
        leafnode = new DefaultMutableTreeNode("本机磁盘(E:)");
        node2.add(leafnode);
       
        DefaultMutableTreeNode node31 = new DefaultMutableTreeNode("网站列表");
        node3.add(node31);
       
        leafnode = new DefaultMutableTreeNode("天勤网站");
        node31.add(leafnode);
        leafnode = new DefaultMutableTreeNode("足球消息");
        node31.add(leafnode);
        leafnode = new DefaultMutableTreeNode("网络书店");
        node31.add(leafnode);
       
        JTree tree = new JTree(root);
        tree.setEditable(true);//设置JTree为可编辑的
        tree.addMouseListener(new MouseHandle());//使Tree加入检测Mouse事件，以便取得节点名称
        //下面两行取得DefaultTreeModel,并检测是否有TreeModelEvent事件.
        DefaultTreeModel treeModel = (DefaultTreeModel)tree.getModel();
        treeModel.addTreeModelListener(this);
       
        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setViewportView(tree);
       
        label = new JLabel("更改数据为: ");
        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);
            }
        });

    }
    /*本方法实作TreeModelListener接口，本接口共定义四个方法，分别是TreeNodesChanged()
     *treeNodesInserted()、treeNodesRemoved()、treeNodesRemoved()、
     *treeStructureChanged().在此范例中我们只针对更改节点值的部份，因此只实作
     *treeNodesChanged()方法.
     */
    public void treeNodesChanged(TreeModelEvent e) {
       
        TreePath treePath = e.getTreePath();
        System.out.println(treePath);
        //下面这行由TreeModelEvent取得的DefaultMutableTreeNode为节点的父节点，而不是用户点选
        //的节点，这点读者要特别注意。要取得真正的节点需要再加写下面6行代码.
        DefaultMutableTreeNode node = (DefaultMutableTreeNode)treePath.getLastPathComponent();
        try {
            //getChildIndices()方法会返回目前修改节点的索引值。由于我们只修改一个节点，因此节点索引值就放在index[0]
            //的位置，若点选的节点为root node,则getChildIndices()的返回值为null,程序下面的第二行就在处理点选root
            //node产生的NullPointerException问题.
            int[] index = e.getChildIndices();
              //由DefaultMutableTreeNode类的getChildAt()方法取得修改的节点对象.
            node = (DefaultMutableTreeNode)node.getChildAt(index[0]);
        } catch (NullPointerException exc) {}
        //由DefaultMutableTreeNode类getUserObject()方法取得节点的内容，或是写成node.toString()亦相同.
        label.setText(nodeName+"更改数据为: "+(String)node.getUserObject());
    }
    public void treeNodesInserted(TreeModelEvent e) {
    }
    public void treeNodesRemoved(TreeModelEvent e) {
    }
    public void treeStructureChanged(TreeModelEvent e) {
    }

    public static void main(String args[]) {
   
        new TreeDemo5();
    }
    //处理Mouse点选事件
    class MouseHandle extends MouseAdapter
    {
        public void mousePressed(MouseEvent e)
        {
            try{
              JTree tree = (JTree)e.getSource();
        //JTree的getRowForLocation()方法会返回节点的列索引值。例如本例中，“本机磁盘(D:)”的列索引值为4,此索引值
        //会随着其他数据夹的打开或收起而变支，但“资源管理器”的列索引值恒为0.
              int rowLocation = tree.getRowForLocation(e.getX(), e.getY());

             /*JTree的getPathForRow()方法会取得从root node到点选节点的一条path,此path为一条直线，如程序运行的图示
              *若你点选“本机磁盘(E:)”,则Tree Path为"资源管理器"-->"我的电脑"-->"本机磁盘(E:)",因此利用TreePath
              *的getLastPathComponent()方法就可以取得所点选的节点.
              */

              TreePath treepath = tree.getPathForRow(rowLocation);
              TreeNode treenode = (TreeNode) treepath.getLastPathComponent();
       
              nodeName = treenode.toString();
            }catch(NullPointerException ne){}
        }
    }
}

注:上面的程序MouseHandle中:
              int rowLocation = tree.getRowForLocation(e.getX(), e.getY());
              TreePath treepath = tree.getPathForRow(rowLocation);
   与：
              TreePath treepath=tree.getSelectionPath();
              等价，可互换。
 
  我们将“我的电脑”改成“网上领居”:
  我们再来看一个TreeModelEvent的例子，下面这个例子我们可以让用户自行增加、删除与修改节点：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import com.incors.plaf.alloy.*;
import com.incors.plaf.alloy.themes.bedouin.*;

public class TreeDemo6 implements ActionListener,TreeModelListener{
  JLabel label=null;
  JTree  tree=null;
  DefaultTreeModel treeModel=null;
  String nodeName=null;//原有节点名称
 
  public TreeDemo6(){
        try {
        AlloyLookAndFeel.setProperty("alloy.isLookAndFeelFrameDecoration", "true");
        AlloyTheme theme = new BedouinTheme();
        LookAndFeel alloyLnF = new AlloyLookAndFeel(theme);
            UIManager.setLookAndFeel(alloyLnF);
        } catch (UnsupportedLookAndFeelException ex) {
        // You may handle the exception here
        }
         // this line needs to be implemented in order to make JWS work properly
        UIManager.getLookAndFeelDefaults().put("ClassLoader", getClass().getClassLoader());
    JFrame f=new JFrame("TreeDemo6");
    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()操作，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 TreeDemo6();
    }
   
    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){}
      }
    }
}

10-7-2：处理TreeSelectionEvent事件：
    当我们在JTree上点选任何一个节点，都会触发TreeSelectionEvent事件，如果我们要处理这样的事件，必须实作
TreeSelectionListener界面，此界面只定义了一个方法，那就是valueChanged()方法。
    TreeSelectionEvent最常用在处理显示节点的内容，例如你在文件图标中点两下就可以看到文件的内容。在JTree中选择节点
的方式共有3种，这3种情况跟选择JList上的项目是一模一样的，分别是：
      DISCONTIGUOUS_TREE_SELECTION:可作单一选择，连续点选择（按住[Shift]键），不连续选择多个节点（按住[Ctrl]键）,
这是java默认值.
      CONTINUOUS_TREE_SELECTION:按住[Shift]键，可对某一连续的节点区间作选取。
      SINGLE_TREE_SELECTION:一次只能选一个节点。
   你可以自行实作TreeSelectionModel制作作更复杂的选择方式，但通常是没有必要的，因为java提供了默认的选择模式类供我们
使用，那就是DefaultTreeSelectionModel,利用这个类我们可以很方便的设置上面3种选择模式。
   下面这个范例，当用户点选了一个文件名时，就会将文件的内容显示出来。
TreeDemo7.java

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import com.incors.plaf.alloy.*;
import com.incors.plaf.alloy.themes.glass.*;

public class TreeDemo7 implements TreeSelectionListener
{
    JEditorPane editorPane;

    public TreeDemo7()
    {
        JFrame f = new JFrame("TreeDemo");
        Container contentPane = f.getContentPane();
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("资源管理器");
        DefaultMutableTreeNode node = new DefaultMutableTreeNode("TreeDemo1.java");
        root.add(node);
        node = new DefaultMutableTreeNode("TreeDemo2.java");
        root.add(node);
        node = new DefaultMutableTreeNode("TreeDemo3.java");
        root.add(node);
        node = new DefaultMutableTreeNode("TreeDemo4.java");
        root.add(node);
       
        JTree tree = new JTree(root);
        //设置Tree的选择模式为一次只能选择一个节点
        tree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
        //检查是否有TreeSelectionEvent事件。
        tree.addTreeSelectionListener(this);

        //下面五行，JSplitPane中，左边是放含有JTree的JScrollPane,右边是放JEditorPane.
        JScrollPane scrollPane1 = new JScrollPane(tree);
        editorPane = new JEditorPane();
        JScrollPane scrollPane2 = new JScrollPane(editorPane);
        JSplitPane splitPane = new JSplitPane(
        JSplitPane.HORIZONTAL_SPLIT,true, scrollPane1, scrollPane2);

        contentPane.add(splitPane);
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
    //本方法实作valueChanged()方法
    public void valueChanged(TreeSelectionEvent e)
    {
        JTree tree = (JTree) e.getSource();
        //利用JTree的getLastSelectedPathComponent()方法取得目前选取的节点.
        DefaultMutableTreeNode selectionNode =
            (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();

        String nodeName = selectionNode.toString();
       
        //判断是否为树叶节点，若是则显示文件内容，若不是则不做任何事。
        if (selectionNode.isLeaf())
        {
           /*取得文件的位置路径,System.getProperty("user.dir")可以取得目前工作的路径，
            *System.getProperty("file.separator")是取得文件分隔符，例如在window环境的
            *文件分陋符是"\",而Unix环境的文件分隔符刚好相反，是"/".利用System.getProperty()
            *方法你可以取得下列的信息:
            java.version                             显示java版本
            java.endor                               显示java制造商
            java.endor.url                           显示java制造商URL
            java.home                                显示java的安装路径
            java.class.version                       显示java类版本
            java.class.path                          显示java classpath
            os.name                                  显示操作系统名称
            os.arch                                  显示操作系统结构，如x86
            os.version                               显示操作系统版本
            file.separator                           取得文件分隔符
            path.separator                           取得路径分隔符，如Unix是以“:”表示
            line.separator                           取得换行符号，如Unix是以"\n"表示
            user.name                                取得用户名称
            user.home                                取得用户家目录(home directory),如Windows中Administrator的家目
                                                     录为c:\Documents and Settings\Administrator
            user.dir                                 取得用户目前的工作目录.
            */
            String filepath = "file:"+System.getProperty("user.dir") +
                               System.getProperty("file.separator") +
                               nodeName;
                          
            try {
               //利用JEditorPane的setPage()方法将文件内容显示在editorPane中。若文件路径错误，则会产生IOException.
                 editorPane.setPage(filepath);
            } catch(IOException ex) {
                 System.out.println("找不到此文件");
            }
        }
    }
   
    public static void main(String[] args) {
    SwingUtil.setLookAndFeel();
        new TreeDemo7();       
    }
}             

class SwingUtil{
  public static final void setLookAndFeel() {
  try{
            Font font = new Font("JFrame", Font.PLAIN, 12);
            Enumeration keys = UIManager.getLookAndFeelDefaults().keys();

            while (keys.hasMoreElements()) {
               Object key = keys.nextElement();
               if (UIManager.get(key) instanceof Font) {
                  UIManager.put(key, font);
                }
            }
        AlloyLookAndFeel.setProperty("alloy.isLookAndFeelFrameDecoration", "true");
        AlloyTheme theme = new GlassTheme();
        LookAndFeel alloyLnF = new AlloyLookAndFeel(theme);
           JFrame.setDefaultLookAndFeelDecorated(true);
         
           UIManager.setLookAndFeel(alloyLnF);
  }catch(UnsupportedLookAndFeelException ex){
    ex.printStackTrace();
  }
}
}

10-8:JTree的其他操作:
     我们在之前小节中曾说到Tree中的每一个节点都是一个TreeNode,并可利用JTree的setEditable()方法设置节点是否可编辑，
若要在Tree中找寻节点的父节点或子节点，或判断是否为树节点，皆可由实作TreeNode界面做到，但要编辑节点呢？java将编辑
节点的任务交给TreeCellEditor,TreeCellEditor本身是一个界面，里面只定义了getTreeCellEditor Component()方法，你可以实
作此方法使节点具有编辑的效果。不过你不用这么辛苦去实作这个方法，java本身提供了DefaultTreeCellEditor类来实作此方法
，亦提供了其他许多方法，例如取得节点内容(getCellEditorValue()) 、设置节点字体(setFont())、决定节点是否可编辑
(isCellEditable())等等。除非你觉得DefaultTreeCellEditor所提供的功能不够，你才需要去实作TreeCellEditor界面。你可以利
用JTree的getCellEditor()方法取得DefaultTreeCellEditor对象。当我们编辑节点时会触发ChangeEvent事件，你可以实作
CellEditorListener界面来处理此事件，CellEditorListener界面包括两个方法，分别是editingStopped(ChangeEvent e)与
editingCanceled(ChangeEvent e).若你没有实作TreeCellEditor界面，系统会以默认的DefaultTreeCellEdtior类来处理掉这两个
方法(你可以在DefaultTreeCellEditor中找到这两个方法)，因此你无须再编写任何的程序。
     另外，JTree还有一种事件处理模式，那就是TreeExpansionEvent事件。要处理这个事件你必须实作TreeExpansionListener
界面，此界面定义了两个方法，分别是treeCollapsed(TreeExpansionEvent e)与treeExpanded(TreeExpansionEvent e).当节点展
开时系统就会自动调用treeExpanded()方法，当节点合起来时，系统就会自动调用treeCollapsed()方法。你可以在这两个方法中编
写所要处理事情的程序代码。处理事件的过程我们已在上面举过多次，这里就不再重复了，可参考下面的网站：
    http://javaalmanac.com/egs/index.html

评论

1 楼 fenger_chui 2012-09-19  

看你的JAVA SWING发表的比较多文章，老兄现在主要在做C/S呢？