Programa para Descargar archivos desde un FTP

Como estoy haciendo un proyecto de una aplicación para el móvil que descarga directorios de un FTP
he decidido publicar mis avances y si alguno lo lee y sabe quizás puede alguien me ayude.

Aquí esta la librería que lista y descarga el directorio
//    DOwnload Gui User 0.5
//
//
//    This file is part of Dogu.
//    Dogu is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    at your option) any later version.
//
//    Foobar is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with Foobar.  If not, see .
//    
//
//    Jaime Velasco Garcia << Salajadin98@gmail.com >>
//  
//    








public class FTPUtil {

public static void downloadDirectory(FTPClient ftpClient, String parentDir,
        String currentDir, String saveDir) throws IOException {
    String dirToList = parentDir;
    if (!currentDir.equals("")) {
        dirToList += "/" + currentDir;
    }

    FTPFile[] subFiles = ftpClient.listFiles(dirToList);

    if (subFiles != null && subFiles.length > 0) {
        for (FTPFile aFile : subFiles) {
            String currentFileName = aFile.getName();
            if (currentFileName.equals(".") || currentFileName.equals("..")) {
                continue;
            }
            String filePath = parentDir + "/" + currentDir + "/"
                    + currentFileName;
            if (currentDir.equals("")) {
                filePath = parentDir + "/" + currentFileName;
            }

            String newDirPath = saveDir + parentDir + File.separator
                    + currentDir + File.separator + currentFileName;
            if (currentDir.equals("")) {
                newDirPath = saveDir + parentDir + File.separator
                          + currentFileName;
            }

            if (aFile.isDirectory()) {
                File newDir = new File(newDirPath);
                boolean created = newDir.mkdirs();
                if (created) {
                    System.out.println("Creado el directorio: " + newDirPath);
                } else {
                    System.out.println("No se pudo crear el directorio: " + newDirPath);
                }

                downloadDirectory(ftpClient, dirToList, currentFileName,
                        saveDir);
            } else {
                boolean success = downloadSingleFile(ftpClient, filePath,
                        newDirPath);
                if (success) {
                    System.out.println("Archivo descargado: " + filePath);
                } else {
                    System.out.println("Error al descargar Archivo: "
                            + filePath);
                }
            }
        }
}

public static boolean downloadSingleFile(FTPClient ftpClient,
        String remoteFilePath, String savePath) throws IOException {
    File downloadFile = new File(savePath);
     
    File parentDir = downloadFile.getParentFile();
    if (!parentDir.exists()) {
        parentDir.mkdir();
    }
         
    OutputStream outputStream = new BufferedOutputStream(
            new FileOutputStream(downloadFile));
    try {
        ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
        return ftpClient.retrieveFile(remoteFilePath, outputStream);
    } catch (IOException ex) {
        throw ex;
    } finally {
        if (outputStream != null) {
            outputStream.close();
        }
    }
}

Y aquí el Main:



//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.

//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//
//  Jaime Velasco Garcia << Salajadin98@gmail.com >>

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see .
import java.io.IOException;

import org.apache.commons.net.ftp.FTPClient;

public class Dogu {

    public static void main(String[] args) {
        String server = "ponerserver";
        int port = 21;
        String user = "poneruser";
        String pass = "ponerpass";
        String codigo;
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);
        System.out.print(“Escribe El Codigo Proporcionado: “);
        codigo = br.readLine();
        FTPClient ftpClient = new FTPClient();

        try {
            ftpClient.connect(server, port);
            ftpClient.login(user, pass);

            ftpClient.enterLocalPassiveMode();

            System.out.println("Conectado");

            String remoteDirPath = "Poner Raiz" + codigo;
            String saveDirPath = "Raiz donde Descargar";

            FTPUtil.downloadDirectory(ftpClient, remoteDirPath, "", saveDirPath);

            ftpClient.logout();
            ftpClient.disconnect();

            System.out.println("Desconectado");
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}




Ahora estoy aprendiendo a hacer la GUI de android