java something

在實(shí)際開發(fā)過程中會經(jīng)常使用JTree組件，平時(shí)會遇到這樣或那樣的問題，在此將偶得一點(diǎn)經(jīng)驗(yàn)寫下來，與大家共享，希望對大家有所幫助。

private JTree jtNetDevice;//數(shù)組件申明
private JScrollPane jspTree;//滾動面板申明

1、初始化
    DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("root");
    jtNetDevice = new JTree(rootNode);
    jtNetDevice.setAutoscrolls(true);
    getTreeSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);//設(shè)置單選模式
    jspTree = new JScrollPane();
    jspTree.getViewport().add(jtNetDevice, null);

2、三個經(jīng)常使用的取值函數(shù)
  private DefaultTreeModel getTreeModel(){
    return (DefaultTreeModel)jtNetDevice.getModel();
  }

  private DefaultMutableTreeNode getRootNode(){
    return (DefaultMutableTreeNode)getTreeModel().getRoot();
  }
 
  private TreeSelectionModel getTreeSelectionModel(){
    return jtNetDevice.getSelectionModel();
  }
 

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

4、根據(jù)Path展開到該節(jié)點(diǎn)
  jtNetDevice.makeVisible(visiblePath);

5、根據(jù)path設(shè)定該節(jié)點(diǎn)選定
  jtNetDevice.setSelectionPath(visiblePath);

6、選中節(jié)點(diǎn)的方法
  首先，根據(jù)節(jié)點(diǎn)得到樹路徑，其中chosen為需要選中的節(jié)點(diǎn)
  TreePath visiblePath = new TreePath( ( (DefaultTreeModel) jtNetDevice.getModel()).
                                        getPathToRoot(chosen));
  然后根據(jù)Path選中該節(jié)點(diǎn)
  jtNetDevice.setSelectionPath(visiblePath);

7、滾動到可見位置
  jtNetDevice.scrollPathToVisible(visiblePath);

8、給JTree添加右鍵彈出菜單
  void jtNetDevice_mouseReleased(MouseEvent e) {
    if (e.isPopupTrigger()) {
      jPopupMenu1.show(e.getComponent(), e.getX(), e.getY());//彈出右鍵菜單
    }
  }

9、關(guān)于JTree的展開
   // 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、如何遍歷JTree
   // 創(chuàng)建樹
   JTree tree = new JTree();
  
   // 添加樹節(jié)點(diǎn)......
  
   // 遍歷所有節(jié)點(diǎn)
   visitAllNodes(tree);
  
   // 僅遍歷展開的節(jié)點(diǎn)
   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);
           }
       }
   }