在實際開發過程中會經常使用JTree組件，平時會遇到這樣或那樣的問題，在此將偶得一點經驗寫下來，與大家共享，希望對大家有所幫助。
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在實際開發過程中會經常使用JTree組件，平時會遇到這樣或那樣的問題，在此將偶得一點經驗寫下來，與大家共享，希望對大家有所幫助。
程序代碼
private JTree jtNetDevice;//數組件申明
private JScrollPane jspTree;//滾動面板申明
1、初始化
程序代碼
DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("root");
jtNetDevice = new JTree(rootNode);
jtNetDevice.setAutoscrolls(true);
getTreeSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SelectION);//設置單選模式
jspTree = new JScrollPane();
jspTree.getViewport().add(jtNetDevice, null);
2、三個經常使用的取值函數
程序代碼
private DefaultTreeModel getTreeModel(){
return (DefaultTreeModel)jtNetDevice.getModel();
}
private DefaultMutableTreeNode getRootNode(){
return (DefaultMutableTreeNode)getTreeModel().getRoot();
}
private TreeSelectionModel getTreeSelectionModel(){
return jtNetDevice.getSelectionModel();
}
3、根據node得到path：
程序代碼
TreePath visiblePath = new TreePath(getTreeModel().getPathToRoot(node));
4、根據Path展開到該節點
程序代碼
jtNetDevice.makeVisible(visiblePath);
5、根據path設定該節點選定
程序代碼
jtNetDevice.setSelectionPath(visiblePath);
6、選中節點的方法
首先，根據節點得到樹路徑，其中chosen為需要選中的節點
程序代碼
TreePath visiblePath = new TreePath( ( (DefaultTreeModel) jtNetDevice.getModel()).
getPathToRoot(chosen));
然后根據Path選中該節點
程序代碼
jtNetDevice.setSelectionPath(visiblePath);
7、滾動到可見位置
程序代碼
jtNetDevice.scrollPathToVisible(visiblePath);
8、給JTree添加右鍵彈出菜單
程序代碼
void jtNetDevice_mouseReleased(MouseEvent e) {
if (e.isPopupTrigger()) {
jPopupMenu1.show(e.getComponent(), e.getX(), e.getY());//彈出右鍵菜單
}
}
9、關于JTree的展開
程序代碼
// 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
// 創建樹
程序代碼
JTree tree = new JTree();
// 添加樹節點......
// 遍歷所有節點
visitAllNodes(tree);
// 僅遍歷展開的節點
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);
}
}
}
文章來源:
http://www.ialvin.cn/blog/default.asp?id=74