Android: How do I change the file name of downloaded files?

Question

I want to change the filename of the files I'm downloading from the internet with the help of an xml file:

<?xml version="1.0" encoding="ISO-8859-1" ?> 
<Phonebook>
    <PhonebookEntry>
        <firstname>Michael</firstname> 
        <lastname>De Leon</lastname> 
        <Address>5, Cat Street</Address> 
        <FileURL>http://www.technobuzz.net/wp-content/uploads/2009/09/Android-Emulator.jpg</FileURL> 
    </PhonebookEntry>
    <PhonebookEntry>
        <firstname>John</firstname> 
        <lastname>Smith</lastname> 
        <Address>6, Dog Street</Address> 
        <FileURL>http://www.cellphonehits.net/uploads/2008/10/android_openmoko.jpg</FileURL> 
    </PhonebookEntry>
    <PhonebookEntry>
        <firstname>Jember</firstname> 
        <lastname>Dowry</lastname> 
        <Address>7, Monkey Street</Address> 
        <FileURL>http://www.techdigest.tv/android.jpg</FileURL> 
    </PhonebookEntry>
</Phonebook>

My program has the following codes:

package com.example.parsingxml;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Iterator;
import java.util.List;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.widget.TextView;
public class ParsingXML extends Activity {

    public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
    private ProgressDialog mProgressDialog;
    public String FileName = "";
    public String FileURL = "";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle) {
         super.onCreate(icicle);

         /* Create a new TextView to display the parsingresult later. */
         TextView tv = new TextView(this);
         tv.setText("This is the parsing program...");


         try {
              /* Create a URL we want to load some xml-data from. */
              URL url = new URL("http://cloud.eacomm.com/jm/sampleXML.xml");
              url.openConnection();
              /* Get a SAXParser from the SAXPArserFactory. */
              SAXParserFactory spf = SAXParserFactory.newInstance();
              SAXParser sp = spf.newSAXParser();

              /* Get the XMLReader of the SAXParser we created. */
              XMLReader xr = sp.getXMLReader();
              /* Create a new ContentHandler and apply it to the XML-Reader*/
              ExampleHandler myExampleHandler = new ExampleHandler();
              xr.setContentHandler(myExampleHandler);

              /* Parse the xml-data from our URL. */
              xr.parse(new InputSource(url.openStream()));
              /* Parsing has finished. */

              /* Our ExampleHandler now provides the parsed data to us. */
              List<ParsedExampleDataSet> parsedExampleDataSet = myExampleHandler.getParsedData();

              /* Set the result to be displayed in our GUI. */
              //tv.setText(parsedExampleDataSet.toString());
              Iterator i;
              i = parsedExampleDataSet.iterator();
              ParsedExampleDataSet dataItem;
              while(i.hasNext()){

                   dataItem = (ParsedExampleDataSet) i.next();
                   tv.append("\n" + dataItem.getfirstname());
                   tv.append("\n" + dataItem.getFileURL());
                   tv.append("\n" + dataItem.getAddress());
                   this.FileName = dataItem.getfirstname() + ".jpg";
                   this.FileURL = dataItem.getFileURL();
                   startDownload();

              }

         } catch (Exception e) {
              /* Display any Error to the GUI. */
              tv.setText("Error: " + e.getMessage());

         }
         /* Display the TextView. */
         this.setContentView(tv);
    }

    private void startDownload(){
        new DownloadFileAsync().execute(FileURL);
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
            case DIALOG_DOWNLOAD_PROGRESS:
                mProgressDialog = new ProgressDialog(this);
                mProgressDialog.setMessage("Downloading file..");
                mProgressDialog.setIndeterminate(false);
                mProgressDialog.setMax(100);
                mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
                mProgressDialog.setCancelable(true);
                mProgressDialog.show();
                return mProgressDialog;
            default:
                return null;
        }
    }


    class DownloadFileAsync extends AsyncTask<String, String, String>{

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            showDialog(DIALOG_DOWNLOAD_PROGRESS);
        }


        @Override
        protected String doInBackground(String... aurl) {

            try {
                File root = Environment.getExternalStorageDirectory();
                URL u = new URL(FileURL);
                HttpURLConnection c = (HttpURLConnection) u.openConnection();
                c.setRequestMethod("GET");
                c.setDoOutput(true);
                c.connect();

                int lenghtOfFile = c.getContentLength();

                FileOutputStream f = new FileOutputStream(new File(root + "/download/", FileName));

                InputStream in = c.getInputStream();

                byte[] buffer = new byte[1024];
                int len1 = 0;
                long total = 0;

                while ((len1 = in.read(buffer)) > 0) {
                    total += len1; //total = total + len1
                    publishProgress("" + (int)((total*100)/lenghtOfFile));
                    f.write(buffer, 0, len1);
                }
                f.close();
            } catch (Exception e) {
                Log.d("Downloader", e.getMessage());
            }

            return null;

        }


        protected void onProgressUpdate(String... progress) {
            Log.d("ANDRO_ASYNC",progress[0]);
            mProgressDialog.setProgress(Integer.parseInt(progress[0]));
       }

       @Override
       protected void onPostExecute(String unused) {
           dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
       }


    }

}

As you can see, the filename of downloaded file is supposedly .jpg, but when I look in my sdcard/download/, the only downloaded file is Jember.jpg. I do believe that it just overwrites the other two files. How can I output Michael.jpg, John.jpg and Jember.jpg?

Answer 1

Your problem is this...

while(i.hasNext()) {
    ...
    this.FileName = dataItem.getfirstname() + ".jpg";
    ...
    startDownload();
}

Basically, startDownload() simply starts an AsyncTask which means it returns immediately. Running through the while loop means the FileName will end up being the last one (most likely) before any of the AsyncTasks complete.

I'd pretty much relocate everything in the try/catch block of your onCreate() method into DownloadFileAsync doInBackground(), only create one instance and just let it handle the parsing and iteration.

Answer 2

Easy, because you're using the instance variables (FileUrl, FileName) to download/store the file, instead of the value that you're passing in to the AsyncTask. Do this when calling the AsyncTask:

  new DownloadFileAsync().execute(currentUrl, currentFile);

Then, inside the doInBackground:

  @Override
  protected String doInBackground(String... strings) {
    String url = strings[0];
    String fileName = strings[1];
    ...
  }