How to list root file systems in Java ME

Overview

This article shows how to list currently mounted root file systems on a device. FileConnection API (JSR-75) has FileSystemRegistry.listRoots() method for this purpose.

The full source code for a test MIDlet:

Source code: RootMIDlet.java

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.Enumeration;
import javax.microedition.io.file.*;
 
public class RootMIDlet extends MIDlet implements CommandListener {
    private Form form;
    private Command exitCommand;
 
    public void startApp() {
        form = new Form("Root list");
        exitCommand = new Command("Exit", Command.EXIT, 1);
        form.addCommand(exitCommand);
        form.setCommandListener(this);
        Display.getDisplay(this).setCurrent(form);
        createRootList();
    }
 
    public void pauseApp() {
    }
 
    public void destroyApp(boolean unconditional) {
    }
 
    protected void createRootList() {
        form.append("Roots:\n");
        Enumeration drives = FileSystemRegistry.listRoots();
        while (drives.hasMoreElements()) {
            String driveString = drives.nextElement().toString();
            form.append(driveString + "\n");
        }
    }
 
    public void commandAction(Command c, Displayable d) {
        if (c == exitCommand) this.notifyDestroyed();
    }
}

See also

• How to write data to a file in Java ME
• How to read an image from Gallery in Java ME
• How to list files and folders in Java ME