java - 如何在 JTree 中显示完整的文件路径?
问题描述
当我单击文件树中的文件时,我想打印出整个文件路径。当我点击一个文件时,它只打印出该行的路径名System.out.println( tree.getLastSelectedPathComponent());
我试图File file = (File) tree.getPath();
获取完整路径,但出现错误(java.lang.ClassCastException:javax.swing.tree.DefaultMutableTreeNode 无法转换为 java.io.File)。
我的完整代码如下
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class NewerFileTree extends JPanel implements Runnable {
protected static final String File = null;
private DefaultMutableTreeNode root;
private DefaultTreeModel treeModel;
private JTree tree;
public void run() {
JFrame frame = new JFrame("File Browser");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
File fileRoot = new File("C://");
root = new DefaultMutableTreeNode(new FileNode(fileRoot));
treeModel = new DefaultTreeModel(root);
tree = new JTree(treeModel);
tree.setShowsRootHandles(true);
JScrollPane scrollPane = new JScrollPane(tree);
tree.addTreeSelectionListener(new TreeSelectionListener() {
public void valueChanged(TreeSelectionEvent event) {
File file = (File) tree.getLastSelectedPathComponent();
System.out.println(tree.getLastSelectedPathComponent());
}
});
frame.add(scrollPane);
frame.setLocationByPlatform(true);
frame.setSize(640, 480);
frame.setVisible(true);
CreateChildNodes ccn
= new CreateChildNodes(fileRoot, root);
new Thread(ccn).start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new NewerFileTree());
}
public class CreateChildNodes implements Runnable {
private DefaultMutableTreeNode root;
private File fileRoot;
public CreateChildNodes(File fileRoot,
DefaultMutableTreeNode root) {
this.fileRoot = fileRoot;
this.root = root;
}
public void run() {
createChildren(fileRoot, root);
}
private void createChildren(File fileRoot,
DefaultMutableTreeNode node) {
File[] files = fileRoot.listFiles();
if (files == null) {
return;
}
for (File file : files) {
DefaultMutableTreeNode childNode
= new DefaultMutableTreeNode(new FileNode(file));
DefaultMutableTreeNode childNodes = new DefaultMutableTreeNode("hello");
node.add(childNode);
if (file.isDirectory()) {
createChildren(file, childNode);
}
}
}
}
public class FileNode {
private File file;
public FileNode(File file) {
this.file = file;
}
@Override
public String toString() {
String name = file.getName();
if (name.equals("")) {
return file.getAbsolutePath();
} else {
return name;
}
}
}
}```
I am working in the `tree.addTreeSelectionListener`.
解决方案
此处看到的修复分为两部分,由 标记/* new */
。基本上:
- 更改
FileNode
以添加一个getFile()
方法(不是绝对必要的,但良好的封装)。 FileNode
从 中获取DefaultMutableTreeNode
,然后File
从那里获取。
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class NewerFileTree extends JPanel implements Runnable {
protected static final String File = null;
private DefaultMutableTreeNode root;
private DefaultTreeModel treeModel;
private JTree tree;
public void run() {
JFrame frame = new JFrame("File Browser");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
File fileRoot = new File("C://");
root = new DefaultMutableTreeNode(new FileNode(fileRoot));
treeModel = new DefaultTreeModel(root);
tree = new JTree(treeModel);
tree.setShowsRootHandles(true);
JScrollPane scrollPane = new JScrollPane(tree);
tree.addTreeSelectionListener(new TreeSelectionListener() {
public void valueChanged(TreeSelectionEvent event) {
/* new */
DefaultMutableTreeNode dmtn = (DefaultMutableTreeNode)
tree.getLastSelectedPathComponent();
FileNode fileNode = (FileNode)dmtn.getUserObject();
File file = fileNode.getFile();
System.out.println(file);
}
});
frame.add(scrollPane);
frame.setLocationByPlatform(true);
frame.setSize(640, 480);
frame.setVisible(true);
CreateChildNodes ccn = new CreateChildNodes(fileRoot, root);
new Thread(ccn).start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new NewerFileTree());
}
public class CreateChildNodes implements Runnable {
private DefaultMutableTreeNode root;
private File fileRoot;
public CreateChildNodes(File fileRoot,
DefaultMutableTreeNode root) {
this.fileRoot = fileRoot;
this.root = root;
}
public void run() {
createChildren(fileRoot, root);
}
private void createChildren(File fileRoot,
DefaultMutableTreeNode node) {
File[] files = fileRoot.listFiles();
if (files == null) {
return;
}
for (File file : files) {
DefaultMutableTreeNode childNode
= new DefaultMutableTreeNode(new FileNode(file));
DefaultMutableTreeNode childNodes = new DefaultMutableTreeNode("hello");
node.add(childNode);
if (file.isDirectory()) {
createChildren(file, childNode);
}
}
}
}
public class FileNode {
private File file;
public FileNode(File file) {
this.file = file;
}
/* new */
public File getFile() {
return file;
}
@Override
public String toString() {
String name = file.getName();
if (name.equals("")) {
return file.getAbsolutePath();
} else {
return name;
}
}
}
}
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