10例子16.txt

这是一本java基础教程 对新手上路有很大帮助

import javax.swing.*; 
import javax.swing.tree.*;	
import java.awt.*;
import javax.swing.event.*;
public class Example10_16{
    public static void main(String args[]){
        new TreeWin(); 
    } 
}
class Student{
    String name;
    double score;
    Student(String name,double score){
       this.name=name;
       this.score=score;
    }
    public String toString(){
       return name;
    }
}
class TreeWin extends JFrame implements TreeSelectionListener{
    JTree tree;
    JTextArea showText;
    TreeWin(){
       DefaultMutableTreeNode root=new DefaultMutableTreeNode("大学");  //根节点
       DefaultMutableTreeNode node=new DefaultMutableTreeNode("学生"); //节点
       DefaultMutableTreeNode nodeson1=
       new DefaultMutableTreeNode(new Student("张三",99));            //节点
       DefaultMutableTreeNode nodeson2=
       new DefaultMutableTreeNode(new Student("李四",88));            //节点
       DefaultMutableTreeNode nodeson3=
       new DefaultMutableTreeNode(new Student("刘五",77));           //节点
       root.add(node);                                            //确定节点之间的关系
       node.add(nodeson1);                                        //确定节点之间的关系
       node.add(nodeson2);
       node.add(nodeson3);
       tree=new JTree(root);                                      //用root做根的树组件
       tree.addTreeSelectionListener(this);                          //监视树组件上的事件
       showText=new JTextArea();
       setLayout(new GridLayout(1,2)); 
       add(new JScrollPane(tree));
       add(new JScrollPane(showText));
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       setVisible(true);
       setBounds(80,80,300,300);
       validate();
    }
    public void valueChanged(TreeSelectionEvent e){
       DefaultMutableTreeNode node=
       (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
       if(node.isLeaf()){
           Student s=(Student)node.getUserObject();                //得到节点中存放的对象
           showText.append(s.name+","+s.score+"\n");  
       }
       else{
           showText.setText(null);
       }   
    }
}