Java如何获取JTree的选定节点？
下面的示例演示如何使用该JTree.getSelectionPaths()方法来获取JTree组件的选定节点。此方法返回一个TreePath对象数组。如果要获取路径中的最后一个节点，我们可以调用TreePath.getLastPathComponent()。
在下面的代码中，当您按下按钮时，侦听器将获取选择路径并打印出所选节点的最后一个路径部分。
package org.nhooo.example.swing;
import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class JTreeGetSelectedNode extends JFrame {
public JTreeGetSelectedNode() throws HeadlessException {
initializeUI();
}
private void initializeUI() {
setSize(200, 400);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("Countries");
DefaultMutableTreeNode asia = new DefaultMutableTreeNode("Asia");
String[] countries = new String[] {"India", "Singapore", "Indonesia", "Vietnam"};
for (String country : countries) {
DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
asia.add(node);
}
DefaultMutableTreeNode northAmerica = new DefaultMutableTreeNode("North America");
countries = new String[] {"United States", "Canada"};
for (String country : countries) {
DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
northAmerica.add(node);
}
DefaultMutableTreeNode southAmerica = new DefaultMutableTreeNode("South America");
countries = new String[] {"Brazil", "Argetina", "Uruguay"};
for (String country : countries) {
DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
southAmerica.add(node);
}
DefaultMutableTreeNode europe = new DefaultMutableTreeNode("Europe");
countries = new String[] {"United Kingdom", "Germany", "Spain", "France", "Italy"};
for (String country : countries) {
DefaultMutableTreeNode node = new DefaultMutableTreeNode(country);
europe.add(node);
}
root.add(asia);
root.add(northAmerica);
root.add(southAmerica);
root.add(europe);
final JTree tree = new JTree(root);
JScrollPane pane = new JScrollPane(tree);
pane.setPreferredSize(new Dimension(200, 400));
JButton button = new JButton("Get Selected");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
TreePath[] paths = tree.getSelectionPaths();
for (TreePath path : paths) {
System.out.println("You've selected: " + path.getLastPathComponent());
}
}
});
getContentPane().setLayout(new BorderLayout());
getContentPane().add(pane, BorderLayout.CENTER);
getContentPane().add(button, BorderLayout.SOUTH);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new JTreeGetSelectedNode().setVisible(true);
}
});
}
}