为 FileExplorerApplication 创建树，但加载速度太慢：<（JAVA、NETBEAN、JTREE、文件资源管理器）

Question

So I want to make Tree for File Explorer, But my code is very slow:< I want to increase Perform of this application (sr My English is not very good):

This is What i Want but it's load too slow 1-2min

This is design view

So this is my code: (I remove initcomponent b/c it's not needed)

public class TreePanel extends javax.swing.JPanel {

    DefaultMutableTreeNode root;
    File[] drives;
    File copyfile,movefile;
    public TreePanel() {
        initComponents();
        drives = GetDrive();
        CreateJtree(drives);
        //ChangeIconNode();

    }
private javax.swing.JTree MyTree;
private javax.swing.JScrollPane jScrollPane1;

private void CreateJtree(File[] drives1) {
    root = new DefaultMutableTreeNode("This PC");

    DefaultTreeModel tree = new DefaultTreeModel(root);
    MyTree.setModel(tree);
    if (drives1 != null) {
        for (File file : drives1) {
            DefaultMutableTreeNode tmp = new DefaultMutableTreeNode(file.getAbsolutePath());
            root.add(tmp);
            AddNodeByRecursive(tmp, file.listFiles());
        }

    }
}

//Image

private Icon ImageResize(ImageIcon imageIcon) {
    int size = 15;
    Image t = imageIcon.getImage().getScaledInstance(size, size, Image.SCALE_SMOOTH);
    return new ImageIcon(t);
}

private void ChangeIconNode() {
    // Change the default JTree icons
    DefaultTreeCellRenderer renderer = (DefaultTreeCellRenderer) MyTree.getCellRenderer();

    Icon closedIcon = ImageResize(new ImageIcon("src/ImagePackages/closed.png"));
    Icon openIcon = ImageResize(new ImageIcon("src/ImagePackages/open.png"));
    Icon leafIcon = ImageResize(new ImageIcon("src/ImagePackages/leaf.png"));
    renderer.setClosedIcon(closedIcon);
    renderer.setOpenIcon(openIcon);
    renderer.setLeafIcon(leafIcon);
    //end of change
}

private File[] GetDrive() {
    return File.listRoots();
}

private void AddNodeByRecursive(DefaultMutableTreeNode root, File[] drives1) {
    if (drives1 == null) {
        return;
    } else {
        for (File file : drives1) {
            DefaultMutableTreeNode tempnode = new DefaultMutableTreeNode(file.getName());
            System.out.println(file.getName());
            root.add(tempnode);
            File[] tempfilearr = file.listFiles();
            AddNodeByRecursive(tempnode, tempfilearr);
        }

    }
}

private void RefreshTree() {
    
    DefaultTreeModel tree = new DefaultTreeModel(root);
    MyTree.setModel(tree);
}

Answer 1

but it's load too slow 1-2min

Sounds like you are trying to build the tree for the entire drive up front. Don't.

Instead, you can dynamically build the tree as the user clicks to expand a node by adding a TreeWillExpand listener to the tree.

Simple example:

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.nio.file.*;

public class TreeFileSystem extends JPanel
    implements ActionListener, TreeWillExpandListener
{
    private int fileIndex;

    private JTree tree;
    private DefaultTreeModel model;

    private JTextField textField;

    public TreeFileSystem()
    {
        super(new BorderLayout());

        textField = new JTextField("c:\\");
        textField.addActionListener( this );
        add(textField, BorderLayout.NORTH);

        tree = new JTree( new DefaultMutableTreeNode() );
        JScrollPane scrollPane = new JScrollPane( tree );
        add(scrollPane);

        tree.addTreeWillExpandListener( this );

        textField.postActionEvent();
    }

    public void actionPerformed(ActionEvent e)
    {
        File file = new File( textField.getText() );

        if (file.exists())
        {
            DefaultMutableTreeNode root = new DefaultMutableTreeNode( file );
            model = new DefaultTreeModel( root );
            addNodes(root, true);
            tree.setModel( model );
        }
    }

    private void addNodes(DefaultMutableTreeNode root, boolean addChildNodes)
    {
        File file = (File)root.getUserObject();
        System.out.println(file);

        if (!file.isDirectory()) return;

        File[] files = file.listFiles(f -> !f.isHidden());

        if (files == null) return;

        int directoryInsert = 0;

        for (int i = 0; i < files.length; i++)
        {
            file = files[i];

            DefaultMutableTreeNode node = new MyDefaultMutableTreeNode( file );

            if (file.isDirectory())
                root.insert(node, directoryInsert++);
            else
                root.insert(node, i);

            if (addChildNodes)
                addNodes(node, false);
        }
    }

    public void treeWillExpand(TreeExpansionEvent e) throws ExpandVetoException
    {
        System.out.println("will expand");
        if (tree.hasBeenExpanded(e.getPath())) return;

        TreePath path = e.getPath();
        System.out.println(path);

        if (path.getPathCount() == 2) return;
        System.out.println(path.getPathCount());

        DefaultMutableTreeNode node = (DefaultMutableTreeNode)path.getPathComponent( path.getPathCount() - 1);
        addNodes(node, false);
    }

    public void treeWillCollapse(TreeExpansionEvent e) {}

    class MyDefaultMutableTreeNode extends DefaultMutableTreeNode
    {
        public MyDefaultMutableTreeNode(Object node)
        {
            super(node);
        }

        public boolean isLeaf()
        {
            File file = (File)getUserObject();

            return file.isFile();
        }
    }

    public static void main(String[] args)
    {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.getContentPane().add( new TreeFileSystem() );
        frame.setSize(300, 400);
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
    }
}