I ran into trouble while writing a piece of code to transfer a bunch of images to my server from a custom app. People recommended Apache FTP for Java. But it can't be used as is since Honeycomb. It needs the task to run on a different thread. This makes the UI far more responsive and is a forced better way to write programs for Android.

Step 1:
First download the zip file called Apache Commons Net from
http://commons.apache.org/net/download_net.cgi

Step 2:
Extract the zip file and copy the file called commons-net-xx.jar Into the libs folder of your Android eclipse project



Step 3: Create a new Java Class with the following code.


package com.example.technologyempoweredjanatainitiative;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.SocketException;
import java.net.UnknownHostException;

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

import android.os.AsyncTask;
import android.util.Log;


public class FTP_Uploader_AsyncTask extends AsyncTask {

//void FTP_DATA_UPLOAD(String FULL_PATH_TO_LOCAL_FILE)


protected Long doInBackground(String... FULL_PATH_TO_LOCAL_FILE ) {
// encapsulate FTP inside a A sync task

{
System.out.println("Entered FTP transfer function");

FTPClient ftpClient = new FTPClient();
int reply;
try {
System.out.println("Entered Data Upload loop!");
   ftpClient.connect("Ftp.example.com",21);
   ftpClient.login("username", "password");
   ftpClient.changeWorkingDirectory("/directory/");
   System.out.println("Entered Data Upload loop!");
 

   reply = ftpClient.getReplyCode();

 
  if(FTPReply.isPositiveCompletion(reply)){
  System.out.println("Connected Success");
  }else {
  System.out.println("Connection Failed");
  ftpClient.disconnect();
  }
 
 
 
   if (ftpClient.getReplyString().contains("250")) {
       ftpClient.setFileType(org.apache.commons.net.ftp.FTP.BINARY_FILE_TYPE);
       BufferedInputStream buffIn = null;
       System.out.println("Created an input stream buffer");
       System.out.println(FULL_PATH_TO_LOCAL_FILE.toString());
     
       buffIn = new BufferedInputStream(new FileInputStream(FULL_PATH_TO_LOCAL_FILE[0]));
       ftpClient.enterLocalPassiveMode();
     
       System.out.println("Entered binary and passive modes");
       //Handler progressHandler=null;
//ProgressInputStream progressInput = new ProgressInputStream(buffIn, progressHandler);

       //Code to Extract name from the string.
       //http://stackoverflow.com/questions/10549504/obtain-name-from-absolute-path-substring-from-last-slash-java-android
       String Picture_File_name = new File(FULL_PATH_TO_LOCAL_FILE[0]).getName();
     
     
       boolean result = ftpClient.storeFile(Picture_File_name, buffIn); //localAsset.getFileName()
       //ProgressInputStream progressInput = new ProgressInputStream(buffIn, progressHandler);
     
       if (result){
        System.out.println("Success");
       }
     
       //boolean result = ftpClient.storeFile("TEST.jpg", progressInput);
       System.out.println("File saved");
     
     
       //buffIn.close();
       ftpClient.logout();
       ftpClient.disconnect();
   }

} catch (SocketException e) {
   Log.e("Citizen Cam FTP", e.getStackTrace().toString());
   System.out.println("Socket Exception!");
} catch (UnknownHostException e) {
   Log.e("Citizen Cam FTP", e.getStackTrace().toString());
} catch (IOException e) {
   Log.e("Citizen Cam FTP", e.getStackTrace().toString());
   System.out.println("IO Exception!");
}

return null;
}


}

}