本文共 6947 字，大约阅读时间需要 23 分钟。
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 [Page] 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 /" ); [Page] 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); [Page] 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(); [Page] // 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(); [Page] 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(); [Page] TreePath path = parent.pathByAddingChild(n); visitAllExpandedNodes(tree, path); } }
转载地址：http://xkxbi.baihongyu.com/