学步园

import java.awt.Dimension;
import java.awt.Color;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.BoxLayout;
import javax.swing.tree.TreePath;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
/*
JTree的构造函数:
JTree()
JTree(Hashtable value)
JTree(Object[] value)//只有这个构造函数可以创建多个根结点
JTree(TreeModel newModel)
JTree(TreeNode root)
JTree(TreeNode root, boolean asksAllowsChildren)
JTree(Vector value)

*/
public class JTreeDemo
{
 public static void main (String[] args)
 {

  //构造函数：JTree()
  JTree example1 = new JTree();

 
  //构造函数：JTree(Object[] value)
  Object[] letters= {"a", "b", "c", "d", "e"};
  JTree example2 = new JTree (letters);

  //构造函数：JTree(TreeNode root)(TreeNode空)
  //用空结点创建树
  DefaultMutableTreeNode node1 = new DefaultMutableTreeNode();//定义树结点
  JTree example3 = new JTree (node1);//用此树结点做参数调用 JTree的构造函数创建含有一个根结点的树

  //构造函数：JTree(TreeNode root)(同上,只是TreeNode非空)
  //用一个根结点创建树
  DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Color");
  JTree example4 = new JTree (node2);//结点不可以颜色,默认为白面黑字
  example4.setBackground (Color.lightGray);

  //构造函数：JTree(TreeNode root, boolean asksAllowsChildren)(同上,只是TreeNode又有不同)
  //使用DefaultMutableTreeNode类先用一个根结点创建树，设置为可添加孩子结点,再添加孩子结点
  DefaultMutableTreeNode color = new DefaultMutableTreeNode("Color", true);
  DefaultMutableTreeNode gray = new DefaultMutableTreeNode ("Gray");
  color.add (gray);
  color.add (new DefaultMutableTreeNode ("Red"));
  gray.add (new DefaultMutableTreeNode ("Lightgray"));
  gray.add (new DefaultMutableTreeNode ("Darkgray"));
  color.add (new DefaultMutableTreeNode ("Green"));
  JTree example5 = new JTree (color);
 
 
 
 
  //构造函数：JTree(TreeNode root)(同上,只是TreeNode非空)
  //通过逐个添加结点创建树
  DefaultMutableTreeNode biology = new DefaultMutableTreeNode ("Biology");
  DefaultMutableTreeNode animal = new DefaultMutableTreeNode ("Animal");
  DefaultMutableTreeNode mammal = new DefaultMutableTreeNode ("Mammal");
  DefaultMutableTreeNode horse = new DefaultMutableTreeNode ("Horse");
  mammal.add (horse);
  animal.add (mammal);
  biology.add (animal);
  JTree example6 = new JTree (biology);
  horse.isLeaf();
  horse.isRoot();
 
 

  //构造函数:JTree(TreeModel newModel)
  //用DefaultMutableTreeNodel类定义一个结点再用这个结点做参数定义一个用DefaultTreeMode
  //创建一个树的模型,再用JTree的构造函数创建一个树
 
  DefaultMutableTreeNode root = new DefaultMutableTreeNode ("Root1");
  DefaultMutableTreeNode child1 = new DefaultMutableTreeNode ("Child1");
  DefaultMutableTreeNode child11 = new DefaultMutableTreeNode ("Child11");
  DefaultMutableTreeNode child111 = new DefaultMutableTreeNode ("Child111");
  root.add (child1); child1.add (child11); child11.add (child111);
 
 
 
  DefaultTreeModel model = new DefaultTreeModel (root);
 
  JTree example7 = new JTree (model);

  JPanel panel = new JPanel();
  panel.setLayout (new BoxLayout (panel, BoxLayout.X_AXIS));
  panel.setPreferredSize (new Dimension (700, 400));
  panel.add (new JScrollPane (example1));//JTree必须放在JScrollPane上
  panel.add (new JScrollPane (example2));
  panel.add (new JScrollPane (example3));
  panel.add (new JScrollPane (example4));
  panel.add (new JScrollPane (example5));
  panel.add (new JScrollPane (example6));
  panel.add (new JScrollPane (example7));
 

  JFrame frame = new JFrame ("JTreeDemo");
  frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
  frame.setContentPane (panel);
  frame.pack();
  frame.show();
 }
}