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JAVA Swing: Load text files into text areas from jTree selection [duplicate]

I am working on developing a GUI using Swing. The GUI is implemented in such a way that the when the user wants to load a set of text files, then the filechooser dialog should open and the user selects the directory in which all the files are present. Now, I want to list all the files in the selected directory into a JScrollPane using JTree. I am using this example to implement JTree in my code:
http://www.java2s.com/Code/Java/File-Input-Output/FileTreeDemo.htm
However, the JTree is not displayed in the JPanel after I select the directory. I have placed the JTree code in the actionPerformed() method. I am not sure if this is the right way.
Here is the code:
public void actionPerformed(ActionEvent e) {
//Handle open button action.
if (e.getSource() == OpenFileButton) {
int returnVal = fc.showOpenDialog(GUIMain.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
file = fc.getSelectedFile();
System.out.println(file);
File[] filesInDirectory = file.listFiles();
SortFile sf = new SortFile();
// Calls sortByNumber method in class SortFile to list the files number wise
filesInDirectory = sf.sortByNumber(filesInDirectory);
FileTreeModel model = new FileTreeModel(file);
tree = new JTree();
tree.setModel(model);
spectralFilesScrollPane = new JScrollPane(tree);
// add(BorderLayout.CENTER, spectralFilesScrollPane);
spectralFilesScrollPane.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
spectralFilesScrollPane.setPreferredSize(new Dimension(250, 145));
spectralFilesScrollPane.setMinimumSize(new Dimension(10, 10));
spectralFilesScrollPane.setBorder(
BorderFactory.createCompoundBorder(
BorderFactory.createTitledBorder("Spectral Files"),
BorderFactory.createEmptyBorder(5, 5, 5, 5)));
content.add(spectralFilesScrollPane);
spectralFilesScrollPane.setVisible(true);
}
}
}
FileTreeModel.java class
import javax.swing.event.TreeModelListener;
import javax.swing.tree.TreeModel;
import javax.swing.*;
import javax.swing.tree.TreePath;
import java.io.File;
/**
* The methods in this class allow the JTree component to traverse
* the file system tree, and display the files and directories.
**/
class FileTreeModel implements TreeModel {
// We specify the root directory when we create the model.
protected File root;
public FileTreeModel(File root) {
System.out.println("I am in FileTree Model");
this.root = root; }
// The model knows how to return the root object of the tree
public Object getRoot() { return root; }
// Tell JTree whether an object in the tree is a leaf or not
public boolean isLeaf(Object node) { return ((File)node).isFile(); }
// Tell JTree how many children a node has
public int getChildCount(Object parent) {
String[] children = ((File)parent).list();
if (children == null) return 0;
System.out.println("printing child length:" + children.length);
return children.length;
}
// Fetch any numbered child of a node for the JTree.
// Our model returns File objects for all nodes in the tree. The
// JTree displays these by calling the File.toString() method.
public Object getChild(Object parent, int index) {
String[] children = ((File)parent).list();
if ((children == null) || (index >= children.length)) return null;
return new File((File) parent, children[index]);
}
// Figure out a child's position in its parent node.
public int getIndexOfChild(Object parent, Object child) {
String[] children = ((File)parent).list();
if (children == null) return -1;
String childname = ((File)child).getName();
for(int i = 0; i < children.length; i++) {
if (childname.equals(children[i])) return i;
}
return -1;
}
// This method is only invoked by the JTree for editable trees.
// This TreeModel does not allow editing, so we do not implement
// this method. The JTree editable property is false by default.
public void valueForPathChanged(TreePath path, Object newvalue) {}
// Since this is not an editable tree model, we never fire any events,
// so we don't actually have to keep track of interested listeners.
public void addTreeModelListener(TreeModelListener l) {}
public void removeTreeModelListener(TreeModelListener l) {}
}
After revalidating the content container, the GUI looks like this:

You haven't revalidated the containing content Container. At the end of your actionPerformed method, add the lines
//content.invalidate();
content.revalidate();
content.repaint();

Java Swing: JTree DefaultMutableTreeNode not updating

I have recently been working on a Java Swing project and today I get stuck when modifying childrens of a DefaultMutableTreeNode.
The following SSCCE illustrates the problem:
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
public class Test
{
private static boolean executed = false;
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//
final DefaultMutableTreeNode root = new DefaultMutableTreeNode("root");
final JTree tree = new JTree(root);
tree.addMouseListener(new MouseAdapter()
{
#Override
public void mousePressed(MouseEvent ev)
{
if (ev.getClickCount() == 2)
{
root.removeAllChildren();
for (String s: get())
{
root.add(new DefaultMutableTreeNode(s));
System.out.println(s + " added");
}
System.out.println();
tree.expandPath(tree.getSelectionPath());
}
}
});
frame.add(tree);
frame.setSize(200,200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
static String[] get()
{
if (!executed)
{
executed = true;
return new String[]{"a","b","c"};
}
else return new String[]{"a","b","c","d"};
}
}
As you see, the first time the get() method is invoked it returns a 3-element array, and a 4-element one afterwards. When I double-click (actually press) the root node for the first time there should be three children nodes (a, b and c), and the program behaves as expected. When I double-click the root node again I suppose it would have four children nodes. However it doesn't. When you double-click for the second time there are still only three, not four children nodes.
Did I make a mistake? Thanks for help in advance.

you should notify the model about changes use reload() method
add this lines before expand path like bellow
DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
model.reload(root); // notify changes to model
tree.expandPath(tree.getSelectionPath());

JTree Edit Root Node?

I am trying to create a JTree I can edit later. So far I have the following code which generates the tree with root node as expected. But, when the button is clicked (triggering the action listener) it adds another node under the root node. What I would rather it do is modify the root node. Is there anyway to do this? I tried changing the various arguments; like a 0 to -1, (MutableTreeNode) treeModel.getRoot() to (MutableTreeNode) treeModel, etc.
Thanks for any help with this.
//Set first as Defualt Node
final DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("You must log in first.");
final DefaultTreeModel treeModel = new DefaultTreeModel(rootNode);
tree_folderList = new JTree(treeModel);
tree_folderList.setEditable(true);
tree_folderList.setBorder(new BevelBorder(BevelBorder.LOWERED));
treescrollPane = new JScrollPane(tree_folderList);
tree_folderList.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
tree_folderList.setShowsRootHandles(true);
//treeModel.addTreeModelListener(new MyTreeModelListener());
ActionListener btn_RefreshMail_Listener = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (sessionkey == null || sessionkey.contains("Invalid")) {
treeModel.insertNodeInto(new DefaultMutableTreeNode("Must be logged in first."), (MutableTreeNode) treeModel.getRoot(), 0);
}
else {
//txt_folderList.setText(DMD.getInbox(sessionkey));
treeModel.insertNodeInto(new DefaultMutableTreeNode("Logged in."), rootNode, 0);
}
}
};

I got it working with the following code. I hope this helps someone else struggling with the same problem. The secret was to create a new defaultnode and then use that with the setroot method.
ActionListener btn_RefreshMail_Listener = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (sessionkey == null || sessionkey.contains("Invalid")) {
DefaultMutableTreeNode rootNode2 = new DefaultMutableTreeNode("You must log in first.");
treeModel.setRoot(rootNode2);
treeModel.reload();
}
else {
//txt_folderList.setText(DMD.getInbox(sessionkey));
DefaultMutableTreeNode rootNode2 = new DefaultMutableTreeNode("Logged in.");
treeModel.setRoot(rootNode2);
treeModel.reload();
}
}
};

List files and directories with Jtree and File in Java

I want to create a very very simple file manager with JTree, but I only saw a very hard code and I want to create this script very clean and simple.
Can you help me? How do I List the directories of my computer in JTree?

I wrote the simplest example of a file browser I could think of. It lists all of the directories and files on the C: drive on a Windows computer.
Here's the result.
And here's the code. I put everything together in one class to make it easier to paste here. You should separate the classes.
package com.ggl.testing;
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class FileBrowser implements Runnable {
private DefaultMutableTreeNode root;
private DefaultTreeModel treeModel;
private JTree tree;
#Override
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);
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 FileBrowser());
}
public class CreateChildNodes implements Runnable {
private DefaultMutableTreeNode root;
private File fileRoot;
public CreateChildNodes(File fileRoot,
DefaultMutableTreeNode root) {
this.fileRoot = fileRoot;
this.root = root;
}
#Override
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));
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;
}
}
}
}

This is how I solved the problem when i encountered it for my project which involved a jtree to show results of my scan.
scanner function is used to initialise the parameters and call the displayDirectoryContents function
Here are some drawbacks of the method i used
It shows empty folders as leaf nodes instead of showing them as a
leaf with no children
The model should be manually cleared by right clicking on the properties and clearing the model
Function used
public void displayDirectoryContents(File dir, DefaultMutableTreeNode root2)
throws InterruptedException {
DefaultMutableTreeNode newdir = new DefaultMutableTreeNode();
// creates array of file type for all the files found
File[] files = dir.listFiles();
for (File file : files) {
if (file == null) {
System.out.println("NUll directory found ");
continue;
}
if (file.isDirectory()) {
// file is a directory that is a folder has been dound
if (file.listFiles() == null) {
// skips null files
continue;
}
// gets the current model of the jtree
DefaultTreeModel model = (DefaultTreeModel) result.getModel();
// gets the root
DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
// generates a node newdir using filename
newdir = new DefaultMutableTreeNode(file.getName());
// adds a node to the root of the jtree
root2.add(newdir);
// refresh the model to show the changes
model.reload();
// recursively calls the function again to explore the contents
// folder
displayDirectoryContents(file, newdir);
} else {
// Else part File is not a directory
// gets the current model of the tree
DefaultTreeModel model = (DefaultTreeModel) result.getModel();
// selected node is the position where the new node will be
// inserted
DefaultMutableTreeNode selectednode = root2;
DefaultMutableTreeNode newfile = new DefaultMutableTreeNode(file.getName());
// inserts a node newfile under selected node which is the root
model.insertNodeInto(newfile, selectednode, selectednode.getChildCount());
// refresh the model to show the changes
model.reload();
}
}
}
Scanner Function to initialise the above function
public void scanner() throws InterruptedException {
// creates a file with the location filename
String location = "C:\\Users\\Ashish Padalkar\\Documents";
File currentDir = new File(location);
// result is the variable name for jtree
DefaultTreeModel model = (DefaultTreeModel) result.getModel();
// gets the root of the current model used only once at the starting
DefaultMutableTreeNode root = (DefaultMutableTreeNode) model.getRoot();
// function caled
displayDirectoryContents(currentDir, root);
}

Adding nodes to programmatically created JTrees in Java

I'm creating this app that creates tabs and JTrees on button click events. The problem is when I try to add ne node to a JTree it doesn't refresh the JTree ( or it doesn't add the node to it ... I don't really know).
This is the functions that creates the tabs and trees:
jTabbedPane1.add(st,jSplitpane10);
int count = jTabbedPane1.getTabCount();
jTabbedPane1.setSelectedIndex(count-1);
DefaultMutableTreeNode root = new DefaultMutableTreeNode("All Notebooks");
DefaultMutableTreeNode notebook1 = new DefaultMutableTreeNode("Notebook 1");
root.add(notebook1);
// Create tree
JTree tree = new JTree(root);
//Create Scroll Pane for the tree
JScrollPane sp = new JScrollPane(tree);
Global.trees.add(tree);
And this is the code that is supposed to add new node "Green" to a tree in the selected tab:
int i = jTabbedPane1.getSelectedIndex();
DefaultTreeModel model = (DefaultTreeModel)Global.trees.get(i).getModel();
// Find node to which new node is to be added
int startRow = 0;
String prefix = "J";
TreePath path = Global.trees.get(i).getNextMatch(prefix, startRow, Position.Bias.Forward);
MutableTreeNode node = (MutableTreeNode)path.getLastPathComponent();
// Create new node
MutableTreeNode newNode = new DefaultMutableTreeNode("green");
// Insert new node as last child of node
model.insertNodeInto(newNode, node, node.getChildCount());
model.reload(newNode);
Here's also the declaration of the global list of JTrees:
public class Global {
public java.util.List<JTree> trees = new ArrayList<JTree>();
}Global Global;
Any ideas why new nodes aren't showing in the trees???

JTree and JTable are the most complex Swing components.
I think is reloaded, but not expanded.
The JTree root node has many settings: how handler or not show root node or not and so on.
I am using a debug console listing where I dump the model data as text ( override the toString() in nodes too) and I can see easily,, what is there, but if you have just a few nodes not needed, it is enough with the Netbeans's debugger.
Also try to expand all rows in tree to have it visible.
Your code is good:
// Create new node
MutableTreeNode newNode = new DefaultMutableTreeNode("green");
// Insert new node as last child of node
model.insertNodeInto(newNode, node, node.getChildCount());
model.reload(newNode);
but probably it is not visible, you need to expand, how to do it, that is another question

Here is some code to add JTree programmatically:
Source:http://sickprogrammersarea.blogspot.in/2014/03/add-jtree-programmatically-in-java-swing.html
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
public class MyTree extends JApplet
{
JTree t;
JLabel l1;
String lang[]={"C","C++","JAVA","PYTHON","AJAX","PHP"};
public void init()
{
try
{
SwingUtilities.invokeAndWait(new Runnable() {
public void run()
{
makeGUI();
}
});
} catch(Exception e){
System.out.println("Sorry some error occured "+e);
}
}
private void makeGUI()
{
DefaultMutableTreeNode top=new DefaultMutableTreeNode("Language");
DefaultMutableTreeNode a=new DefaultMutableTreeNode("Programming");
top.add(a);
DefaultMutableTreeNode a1=new DefaultMutableTreeNode("C");
a.add(a1);
DefaultMutableTreeNode a2=new DefaultMutableTreeNode("Java");
a.add(a2);
DefaultMutableTreeNode b=new DefaultMutableTreeNode("Web Based");
top.add(b);
DefaultMutableTreeNode b1=new DefaultMutableTreeNode("PHP");
b.add(b1);
DefaultMutableTreeNode b2=new DefaultMutableTreeNode("JSP");
b.add(b2);
t=new JTree(top);
JScrollPane scr=new JScrollPane(t);
add(scr);
setLayout(new FlowLayout());
l1=new JLabel("Choose a language");
add(l1,BorderLayout.SOUTH);
t.addTreeSelectionListener(new TreeSelectionListener () {
public void valueChanged(TreeSelectionEvent ae) {
l1.setText(ae.getPath()+" is selected");
}
});
}
}

I produced a small example application to test your issue. I found that the node was being added correctly, but not expanding. Also, the call to model.reload seems unnecessary.
I added a call to expandPath on the tree to cause the display to show the new node. You may need to double check this doesn't expand too much of the tree:
public class Example extends JFrame {
private JTree tree;
public Example() {
DefaultMutableTreeNode root = new DefaultMutableTreeNode("All Notebooks");
DefaultMutableTreeNode notebook1 = new DefaultMutableTreeNode("Notebook 1");
root.add(notebook1);
tree = new JTree(root);
JScrollPane sp = new JScrollPane(tree);
setLayout(new BorderLayout());
add(sp, BorderLayout.CENTER);
add(new JButton("Go") {
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Example.this.addNode();
}
});
}}, BorderLayout.SOUTH);
setDefaultCloseOperation(EXIT_ON_CLOSE);
pack();
}
private void addNode() {
DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
// Find node to which new node is to be added
int startRow = 0;
String prefix = "N";
TreePath path = tree.getNextMatch(prefix, startRow,
Position.Bias.Forward);
MutableTreeNode node = (MutableTreeNode) path.getLastPathComponent();
// Create new node
MutableTreeNode newNode = new DefaultMutableTreeNode("green");
// Insert new node as last child of node
model.insertNodeInto(newNode, node, node.getChildCount());
tree.expandPath(path);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Example().setVisible(true);
}
});
}
}