[英]How do I auto-expand a JTree when setting a new TreeModel?
我有一個自定義JTree
和一個自定義JModel
; 當我給它一個新模型時,我希望 JTree 能夠“自動擴展”。 目前,它只是將所有節點折疊到根節點。
下面是一個例子:
private class CustomTree extends JTree {
@Override
public boolean isExpanded(TreePath path) {
return ((Person) path.getLastPathComponent).hasChildren();
}
private class CustomTreeModel extends TreeModel {
// ... omitting various implementation details
@Override
public boolean isLeaf(Object object) {
return !((Person) object).hasChildren();
}
}
Model model = new Model();
Person bob = new Person();
Person alice = new Person();
bob.addChild(alice);
model.setRoot(bob);
JTree tree = new CustomTree(new CustomTreeModel(model));
此時,樹正確顯示:
- BOB
- ALICE
其中 Alice 是 Bob 的孩子(在數據和可視化樹中)
但是,如果我打電話:
tree.setModel(new CustomTreeModel(model));
一切都崩潰了:
+ BOB
有沒有辦法在設置新模型時“自動擴展”樹中的所有內容?
以下對我有用(在設置新模型后調用):
for (int i = 0; i < tree.getRowCount(); i++) {
tree.expandRow(i);
}
我有一個類似的問題。
您的解決方案(如https://stackoverflow.com/a/15211697/837530發布)似乎僅適用於頂級樹節點。
但是我需要擴展所有的后代節點。 所以我用下面的遞歸方法解決了它:
private void expandAllNodes(JTree tree, int startingIndex, int rowCount){
for(int i=startingIndex;i<rowCount;++i){
tree.expandRow(i);
}
if(tree.getRowCount()!=rowCount){
expandAllNodes(tree, rowCount, tree.getRowCount());
}
}
這是用
expandAllNodes(tree, 0, tree.getRowCount());
其中, tree
是JTree
。
除非有人有更好的解決方案。
還有這個非遞歸版本。
private void expandAllNodes(JTree tree) {
int j = tree.getRowCount();
int i = 0;
while(i < j) {
tree.expandRow(i);
i += 1;
j = tree.getRowCount();
}
}
這對我有用..
import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeNode;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.util.Enumeration;
public class JTreeNodeAutoExpandCollapse extends JFrame {
public JTreeNodeAutoExpandCollapse() throws HeadlessException {
initializeUI();
}
private void initializeUI() {
setSize(200, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
DefaultMutableTreeNode chapter1 = new DefaultMutableTreeNode("Chapter 1");
DefaultMutableTreeNode sub1 = new DefaultMutableTreeNode("1.1");
DefaultMutableTreeNode sub2 = new DefaultMutableTreeNode("1.2");
DefaultMutableTreeNode sub3 = new DefaultMutableTreeNode("1.3");
DefaultMutableTreeNode sub31 = new DefaultMutableTreeNode("1.3.1");
DefaultMutableTreeNode sub32 = new DefaultMutableTreeNode("1.3.2");
root.add(chapter1);
chapter1.add(sub1);
chapter1.add(sub2);
chapter1.add(sub3);
sub3.add(sub31);
sub3.add(sub32);
final JTree tree = new JTree(root);
expandTree(tree, false);
JScrollPane pane = new JScrollPane(tree);
pane.setPreferredSize(new Dimension(200, 200));
JPanel buttonPanel = new JPanel(new BorderLayout());
JButton expandAll = new JButton("Expand All");
expandAll.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
expandTree(tree, true);
}
});
JButton collapseAll = new JButton("Collapse All");
collapseAll.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
expandTree(tree, false);
}
});
buttonPanel.add(expandAll, BorderLayout.WEST);
buttonPanel.add(collapseAll, BorderLayout.EAST);
getContentPane().setLayout(new BorderLayout());
getContentPane().add(pane, BorderLayout.CENTER);
getContentPane().add(buttonPanel, BorderLayout.SOUTH);
}
private void expandTree(JTree tree, boolean expand) {
TreeNode root = (TreeNode) tree.getModel().getRoot();
expandAll(tree, new TreePath(root), expand);
}
private void expandAll(JTree tree, TreePath path, boolean expand) {
TreeNode node = (TreeNode) path.getLastPathComponent();
if (node.getChildCount() >= 0) {
Enumeration enumeration = node.children();
while (enumeration.hasMoreElements()) {
TreeNode n = (TreeNode) enumeration.nextElement();
TreePath p = path.pathByAddingChild(n);
expandAll(tree, p, expand);
}
}
if (expand) {
tree.expandPath(path);
} else {
tree.collapsePath(path);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new JTreeNodeAutoExpandCollapse().setVisible(true);
}
});
}
}
由於我無法編輯或評論接受OP的最后一個問題的接受答案:
在設置新模型時,有沒有辦法“自動擴展”樹中的所有內容?
要在分配新模型后(根據OP的請求)展開樹,請覆蓋自定義樹中的treeDidChange()
:
@Override
public void treeDidChange() {
super.treeDidChange();
expandAllNodes(this, 0, getRowCount());
}
public void expandTree(){
int row = 1;
while (row++ < tree.getRowCount()){
tree.expandRow(row);
}
public void collapseTree(){
int row = tree.getRowCount() - 1;
while (row-- > 0){
tree.collapseRow(row);
}
}
TreeUtils.expandAll(tree, true);
您將從jidesoft獲得TreeUtils。 這不是開源庫,但如果你有它,你可以簡單地擴展所有的treenode。
http://www.jidesoft.com/javadoc/com/jidesoft/tree/TreeUtils.html
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