jtree3.java

JAVA GUI图形界面设计 SWING 组建小用

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

public class JTree3 extends JFrame
{
  JPanel cp=new JPanel();
  JTree jtree;
  DefaultMutableTreeNode root;
  JSplitPane jspane1=new JSplitPane();
  JScrollPane jscrpane1=new JScrollPane();
  JScrollPane jscrpane2=new JScrollPane();
  JTextArea jta1=new JTextArea("tree selected:");

  public JTree3()
  {
   this.setSize(300,300);
   this.setTitle("try to use tree");
   cp=(JPanel)this.getContentPane();
   cp.setLayout(new BorderLayout());

   jspane1.setDividerSize(10);
   jspane1.setOneTouchExpandable(true);
   jspane1.setDividerLocation(150);

   root=new DefaultMutableTreeNode("school");
   createTree(root);
   jtree=new JTree(root);

   jscrpane1.getViewport().add(jtree);
   jspane1.add(jscrpane1,JSplitPane.LEFT);

   jscrpane2.getViewport().add(jta1);
   jspane1.setRightComponent(jscrpane2);
  // jspane1.add(jtree,JSplitPane.LEFT);
   cp.add(jspane1,BorderLayout.CENTER);

   jtree.addTreeSelectionListener(new TreeSelectionListener()
   {
    public void valueChanged(TreeSelectionEvent e)
    {
     DefaultMutableTreeNode node=new DefaultMutableTreeNode();
     node=(DefaultMutableTreeNode)jtree.getLastSelectedPathComponent();
     if(node==null) return;

     Object info=node.getUserObject();
     if(node.isLeaf())
     {
      jta1.append(info.toString()+"is selected,it is a leaf"+"\n");
     }
     else
     {
      jta1.append(info.toString()+"is selected,it is not a leaf"+"\n");
     }
    }
   });

  }

  public static void main(String[] args)
  {
    JTree3 JTree3 = new JTree3();
    JTree3.setVisible(true);
  }

  private void createTree(DefaultMutableTreeNode root)
  {
   DefaultMutableTreeNode classroom=null;
   DefaultMutableTreeNode number=null;

   classroom=new DefaultMutableTreeNode("classroom");
   root.add(classroom);

   for(int i=1;i<=8;i++)
   {
    number=new DefaultMutableTreeNode("No."+String.valueOf(i));

    if(i==4)
    {
     for(int j=1;j<=5;j++)
     {
      number.add(new DefaultMutableTreeNode("seat"+String.valueOf(j)));
     }
    }
   classroom.add(number);
   }
  }

  protected void processWindowEvent(WindowEvent e)
  {
   if(e.getID()==WindowEvent.WINDOW_CLOSING)
   {
    System.exit(0);
   }
  }
}