JTree用法及JTree使用经验总结

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();
	}
}

在实际开发过程中会经常使用JTree组件，平时会遇到这样或那样的问题，在此将偶得一点经验写下来，与大家共享，希望对大家有所帮助。

private JTree jtNetDevice;//数组件申明
private JScrollPane jspTree;//滚动面板申明


1、初始化
    DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("root");
    jtNetDevice = new JTree(rootNode);
    jtNetDevice.setAutoscrolls(true);
    getTreeSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);//设置单选模式
    jspTree = new JScrollPane();
    jspTree.getViewport().add(jtNetDevice, null);

2、三个经常使用的取值函数
  private DefaultTreeModel getTreeModel(){
    return (DefaultTreeModel)jtNetDevice.getModel();
  }

  private DefaultMutableTreeNode getRootNode(){
    return (DefaultMutableTreeNode)getTreeModel().getRoot();
  }

  private TreeSelectionModel getTreeSelectionModel(){
    return jtNetDevice.getSelectionModel();
  }


3、根据node得到path：
  TreePath visiblePath = new TreePath(getTreeModel().getPathToRoot(node));

4、根据Path展开到该节点
  jtNetDevice.makeVisible(visiblePath);

5、根据path设定该节点选定
  jtNetDevice.setSelectionPath(visiblePath);

6、选中节点的方法
  首先，根据节点得到树路径，其中chosen为需要选中的节点
  TreePath visiblePath = new TreePath( ( (DefaultTreeModel) jtNetDevice.getModel()).
                                        getPathToRoot(chosen));
  然后根据Path选中该节点
  jtNetDevice.setSelectionPath(visiblePath);

7、滚动到可见位置
  jtNetDevice.scrollPathToVisible(visiblePath);

8、给JTree添加右键弹出菜单
  void jtNetDevice_mouseReleased(MouseEvent e) {
    if (e.isPopupTrigger()) {
      jPopupMenu1.show(e.getComponent(), e.getX(), e.getY());//弹出右键菜单
    }
  }

9、关于JTree的展开
   // If expand is true, expands all nodes in the tree.
   // Otherwise, collapses all nodes in the tree.
   public void expandAll(JTree tree, boolean expand) {
       TreeNode root = (TreeNode)tree.getModel().getRoot();
 
       // Traverse tree from root
       expandAll(tree, new TreePath(root), expand);
   }
   private void expandAll(JTree tree, TreePath parent, boolean expand) {
       // Traverse children
       TreeNode node = (TreeNode)parent.getLastPathComponent();
       if (node.getChildCount() >= 0) {
           for (Enumeration e=node.children(); e.hasMoreElements(); ) {
               TreeNode n = (TreeNode)e.nextElement();
               TreePath path = parent.pathByAddingChild(n);
               expandAll(tree, path, expand);
           }
       }
 
       // Expansion or collapse must be done bottom-up
       if (expand) {
           tree.expandPath(parent);
       } else {
           tree.collapsePath(parent);
       }
   }


10、如何遍历JTree
   // 创建树
   JTree tree = new JTree();
 
   // 添加树节点......
 
   // 遍历所有节点
   visitAllNodes(tree);
 
   // 仅遍历展开的节点
   visitAllExpandedNodes(tree);
 
   // Traverse all nodes in tree
   public void visitAllNodes(JTree tree) {
       TreeNode root = (TreeNode)tree.getModel().getRoot();
       visitAllNodes(root);
   }
   public void visitAllNodes(TreeNode node) {
       // node is visited exactly once
       process(node);
 
       if (node.getChildCount() >= 0) {
           for (Enumeration e=node.children(); e.hasMoreElements(); ) {
               TreeNode n = (TreeNode)e.nextElement();
               visitAllNodes(n);
           }
       }
   }
 
   // Traverse all expanded nodes in tree
   public void visitAllExpandedNodes(JTree tree) {
       TreeNode root = (TreeNode)tree.getModel().getRoot();
       visitAllExpandedNodes(tree, new TreePath(root));
   }
   public void visitAllExpandedNodes(JTree tree, TreePath parent) {
       // Return if node is not expanded
       if (!tree.isVisible(parent)) {
           return;
       }
 
       // node is visible and is visited exactly once
       TreeNode node = (TreeNode)parent.getLastPathComponent();
       process(node);
 
       // Visit all children
       if (node.getChildCount() >= 0) {
           for (Enumeration e=node.children(); e.hasMoreElements(); ) {
               TreeNode n = (TreeNode)e.nextElement();
               TreePath path = parent.pathByAddingChild(n);
               visitAllExpandedNodes(tree, path);
           }
       }
   }


摘自：http://www.blogjava.net/wangxinsh55/archive/2006/04/04/39219.html