Javafx TreeView Directory Listing

Question

I'm trying to create a TreeView which displays directory contents such as:

ABC
    BCD
    123.php

Where ABC and BCD are both directories. I feel like I'm missing something as the TreeView works fine before I strip out the full directory location but once I strip it, it won't display like the above.

public void displayTreeView(String inputDirectoryLocation, CheckBoxTreeItem<String> mainRootItem) {

    // Creates the root item.
    CheckBoxTreeItem<String> rootItem = new CheckBoxTreeItem<>(inputDirectoryLocation);

    // Hides the root item of the tree view.
    treeView.setShowRoot(false);

    // Creates the cell factory.
    treeView.setCellFactory(CheckBoxTreeCell.<String>forTreeView());

    // Get a list of files.
    File fileInputDirectoryLocation = new File(inputDirectoryLocation);
    File fileList[] = fileInputDirectoryLocation.listFiles();

    // Loop through each file and directory in the fileList.
    for (int i = 0; i < fileList.length; i++) {

        // Check if fileList[i] is a file or a directory.
        if (fileList[i].isDirectory()) {

            // Re-iterate through as is directory.
            displayTreeView(fileList[i].toString(), rootItem);

        } else {

            // Check the file type of the file.
            String fileType = Util.retrieveFileType(fileList[i].toString());

            // Check if the file type is the same file type we are searching for. In the future we just add the or symbol to support other file types.
            if (fileType.equals(".php")) {

                // Creates the item.
                CheckBoxTreeItem<String> fileCheckBoxTreeItem = new CheckBoxTreeItem<>(fileList[i].getName());

                // Adds to the treeview.
                rootItem.getChildren().add(fileCheckBoxTreeItem);
            }
        }
    }

    // Check if the mainRootItem has been specified.
    if (mainRootItem == null) {

        // Sets the tree view root item.
        treeView.setRoot(rootItem);
    } else {

        // Creates the root item.
        CheckBoxTreeItem<String> dirCheckBoxTreeItem = new CheckBoxTreeItem<>(fileInputDirectoryLocation.getName());

        // Sets the sub-root item.
        mainRootItem.getChildren().add(dirCheckBoxTreeItem);
    }
}

Answer 1

Sorry for bumping an old question but I ran into a problem on implementing fabian's answer and I think this might be useful.

Browsing a large directory (e.g. root) can cause a performance issue. I resolved it by making it continue the recursive only after TreeItem is expanded.

private void createTree(File root_file, TreeItem parent) {
    if (root_file.isDirectory()) {
        TreeItem node = new TreeItem(root_file.getName());
        parent.getChildren().add(node);
        for (File f: root_file.listFiles()) {

            TreeItem placeholder = new TreeItem(); // Add TreeItem to make parent expandable even it has no child yet.
            node.getChildren().add(placeholder);

            // When parent is expanded continue the recursive
            node.addEventHandler(TreeItem.branchExpandedEvent(), new EventHandler() {
                @Override
                public void handle(Event event) {
                    createTree(f, node); // Continue the recursive as usual
                    node.getChildren().remove(placeholder); // Remove placeholder
                    node.removeEventHandler(TreeItem.branchExpandedEvent(), this); // Remove event
                }
            });

        }
    } else {
        parent.getChildren().add(new TreeItem(root_file.getName()));
    }
}

Apart from modifying the for loop. I used TreeItem instead of CheckBoxTreeItem and some variable name, the rest is the same.

---

I also ran into another problem with Windows folder/files which's read-only or protected such as $RECYCLE.BIN and System Volume Information. I resolved the issue by checking if the file is system file or hidden or read-only or not. If yes ignore that file/folder.

try {
    DosFileAttributes attr = Files.readAttributes(root_file.toPath(), DosFileAttributes.class);
    if(attr.isSystem() || attr.isHidden() || attr.isReadOnly()) {
        // Do nothing
    } else { ... }
} catch (IOException ex) {
    Logger.getLogger(FXMLMainController.class.getName()).log(Level.SEVERE, null, ex);
}

More info about checking file attributes

Answer 2

By combining the initialisation of the TreeView and a recursive method for constructing the tree you created messy code.

Better create a new method just for creating the tree:

public static void createTree(File file, CheckBoxTreeItem<String> parent) {
    if (file.isDirectory()) {
        CheckBoxTreeItem<String> treeItem = new CheckBoxTreeItem<>(file.getName());
        parent.getChildren().add(treeItem);
        for (File f : file.listFiles()) {
            createTree(f, treeItem);
        }
    } else if (".php".equals(Util.retrieveFileType(file.toString()))) {
        parent.getChildren().add(new CheckBoxTreeItem<>(file.getName()));
    }
}

and use it in your displayTreeView method

public void displayTreeView(String inputDirectoryLocation) {
    // Creates the root item.
    CheckBoxTreeItem<String> rootItem = new CheckBoxTreeItem<>(inputDirectoryLocation);

    // Hides the root item of the tree view.
    treeView.setShowRoot(false);

    // Creates the cell factory.
    treeView.setCellFactory(CheckBoxTreeCell.<String>forTreeView());

    // Get a list of files.
    File fileInputDirectoryLocation = new File(inputDirectoryLocation);
    File fileList[] = fileInputDirectoryLocation.listFiles();

    // create tree
    for (File file : fileList) {
        createTree(file, rootItem);
    }

    treeView.setRoot(rootItem);
}

---

BTW: Your issue is caused by creating the tree structure and ignoring it for every node but the root (for non-root items the only node added to rootItem; for items other than the root you add is the "flat" dirCheckBoxTreeItem to the parent instead).