Develop Reference

Download Multiple Files Using Async

I am trying to download multiple files using asyc but for some reason it only downloads one file successfully while all the other files are 0 bytes.
Only the file that is added first to the string array is downloaded successfully, the rest are written as 0 bytes on the SD card.
class DownloadFileFromFTP extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Bar Dialog
* */
#Override
protected void onPreExecute() {
super.onPreExecute();
//showDialog(progress_bar_type);
}
/**
* Downloading file in background thread
* */
#Override
protected String doInBackground(String... f_url) {
//code
//Read SharedPref
String str_dirRestoredImage_open = sharedPref.getString("SharedPref_dirRestoredImage_open", "");
int count;
OutputStream output = null;
try {
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
int lenghtOfFile = conection.getContentLength();
// download the file
InputStream input = new BufferedInputStream(url.openStream(), 8192);
int totalFilesChecked = arrListStr_Files_Checked.size();
for (int i=0;i<totalFilesChecked;i++)
{
// Output stream
file_name_remote_abs = stringArr_Files_Checked[i];
file_name_remote = file_name_remote_abs.substring(file_name_remote_abs.lastIndexOf('/') + 1);
output = new FileOutputStream(str_dirRestoredImage_open+"/"+file_name_remote);
Log.d("LOG", "zzz_i: "+i +" :"+file_name_remote);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress("" + (int) ((total * 100) / lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
runOnUiThread(new Runnable() {
#Override
public void run() {
// Stuff that updates the UI
Toast.makeText(getApplicationContext(), "File Restored: "+file_name_remote, Toast.LENGTH_LONG).show();
}
});
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("Error: ", e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
// Stuff that updates the UI
Toast.makeText(getApplicationContext(), "Failed To Restore: "+file_name_remote, Toast.LENGTH_LONG).show();
}
});
}
return null;
}
/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
//pDialog.setProgress(Integer.parseInt(progress[0]));
}
/**
* After completing background task Dismiss the progress dialog
* **/
#Override
protected void onPostExecute(String file_url) {
// dismiss the dialog after the file was downloaded
//dismissDialog(progress_bar_type);
}
}
This is how I am calling it, where stringArr_Files_Checked is a string array of absolute URLs of files.
new DownloadFileFromFTP().execute(stringArr_Files_Checked);

ProgressBar get Stucked at 0% while downloading file from server?

I am creating an Android application to download an mp3 file from
server. The downloading is working fine. But the ProgressBar is
stuck at 0% while downloading...
MainActivity.java
public class MainActivity extends Activity {
// button to show progress dialog
Button btnShowProgress;
// Progress Dialog
private ProgressDialog pDialog;
ImageView my_image;
// Progress dialog type (0 - for Horizontal progress bar)
public static final int progress_bar_type = 0;
// File url to download
private static String file_url = "http://eecindia.co.in/up/01%20-%20Pretham%20-%20Oruthikku%20Pinnil%20[Maango.me].mp3";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// show progress bar button
btnShowProgress = (Button) findViewById(R.id.btnProgressBar);
// Image view to show image after downloading
my_image = (ImageView) findViewById(R.id.my_image);
/**
* Show Progress bar click event
* */
btnShowProgress.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// starting new Async Task
new DownloadFileFromURL().execute(file_url);
}
});
}
/**
* Showing Dialog
* */
#Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case progress_bar_type:
pDialog = new ProgressDialog(this);
pDialog.setMessage("Downloading file. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setMax(100);
pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pDialog.setCancelable(false);
pDialog.show();
return pDialog;
default:
return null;
}
}
/**
* Background Async Task to download file
* */
class DownloadFileFromURL extends AsyncTask<String, String, String> {
/**
* Before starting background thread
* Show Progress Bar Dialog
* */
#Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(progress_bar_type);
}
/**
* Downloading file in background thread
* */
#Override
protected String doInBackground(String... f_url) {
int count;
try {
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
InputStream input = new BufferedInputStream(url.openStream(), 8192);
// Output stream to write file
OutputStream output = new FileOutputStream("/sdcard/downloadedfile.mp3");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress(""+(int)((total*100)/lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("Error: ", e.getMessage());
}
return null;
}
/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
pDialog.setProgress(Integer.parseInt(progress[0]));
}
/**
* After completing background task
* Dismiss the progress dialog
* **/
#Override
protected void onPostExecute(String file_url) {
// dismiss the dialog after the file was downloaded
dismissDialog(progress_bar_type);
// Displaying downloaded image into image view
// Reading image path from sdcard
// String imagePath = Environment.getExternalStorageDirectory().toString() + "/downloadedfile.mp3";
// setting downloaded into image view
Toast.makeText(MainActivity.this, "Downloaded Succesfully.. check SD card 2 see file...", Toast.LENGTH_SHORT).show();
//my_image.setImageDrawable(Drawable.createFromPath(imagePath));
}
}
}

the above process works fine for image files but gets stuck for large files then you have to change this code in doinbackground method and see ..it works :)
HttpURLConnection connection = (HttpURLConnection)url.openConnection(); connection.setRequestMethod("HEAD");
connection.connect();
int length = connection.getContentLength();

Same file with same name getting downloaded even when provided with different URLs

I have a activity that contains a listview and sends different url when different list item is clicked via intent in onitemclicklistener
In the singleitemview activity which is opened when list item is clicked i have a button to download images
The problem is only 1 image is getting downloaded even different URLs are provided through different list item clicks
I think this is happening because of providing only 1 outputstream like this
OutputStream output = new FileOutputStream("/sdcard/download/loadedfile.png");
how to change this so each different image gets downloaded with its own file name
onitemclicklistener of listview
public void onItemClick(AdapterView<?> p1, View view, int position, long p4)
{
Intent intent = new Intent(ProActivity.this, SingleItemView.class);
intent.putExtra("download",
(codelist.get(position).getDownloadCode()));
staetActivity(intent);
}
My download class
class DownloadFileFromURL extends AsyncTask<String, String, String>
{
/**
* Before starting background thread
* Show Progress Bar Dialog
* */
#Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(progress_bar_type);
}
/**
* Downloading file in background thread
* */
#Override
protected String doInBackground(String... f_url) {
int count;
try{
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
// this will be useful so that you can show a tipical 0-100% progress bar
int lenghtOfFile = conection.getContentLength();
// download the file
InputStream input = new BufferedInputStream(url.openStream(), 8192);
// Output stream
OutputStream output = new FileOutputStream("/sdcard/download/loadedfile.png");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress(""+(int)((total*100)/lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
//e.printStackTrace();
Log.e("Error: ","Error Message ::" + e.getMessage());
}
return null;
}
/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
pDialog.setProgress(Integer.parseInt(progress[0]));
}
/**
* After completing background task
* Dismiss the progress dialog
* **/
#Override
protected void onPostExecute(String downurl) {
// dismiss the dialog after the file was downloaded
dismissDialog(progress_bar_type);
Toast.makeText(SingleItemView.this,
getString(R.string.download_complete),
Toast.LENGTH_SHORT).show();
}
}
1
onclick method for my download button in singlitemview activity
Intent i = getIntent();
file_url = i.getStringExtra("download");
public void downloadnow(){
// different url is recived from different list item click via intent
String downurl = file_url;
new DownloadFileFromURL().execute(downurl);
}

Try to change file name loadedfile.png to downloaded file name.
Something like:
String fileName = url.substring( url.lastIndexOf('/')+1, url.length() );
OutputStream output = new FileOutputStream("/sdcard/download/" + filename);

Android : Convert XML Too String

I'm load a file from Internet , My Type of file is XML I'm use This Code And I Want Convert My XML To String For Use IN Next Activity . How Convert To0 String And Use In Next Activity ????
private ProgressDialog pDialog;
ImageView my_image;
// Progress dialog type (0 - for Horizontal progress bar)
public static final int progress_bar_type = 0;
// File url to download
private static String file_url = "http://linker.blogsky.com/rss";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loadingc);
// show progress bar button
btnShowProgress = (Button) findViewById(R.id.btnProgressBar);
// Image view to show image after downloading
my_image = (ImageView) findViewById(R.id.my_image);
/**
* Show Progress bar click event
* */
// starting new Async Task
new DownloadFileFromURL().execute(file_url);
}
/**
* Showing Dialog
* */
#Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case progress_bar_type:
pDialog = new ProgressDialog(this);
pDialog.setMessage("Downloading file. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setMax(100);
pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pDialog.setCancelable(true);
pDialog.show();
return pDialog;
default:
return null;
}
}
/**
* Background Async Task to download file
* */
class DownloadFileFromURL extends AsyncTask<String, String, String> {
/**
* Before starting background thread
* Show Progress Bar Dialog
* */
#Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(progress_bar_type);
}
/**
* Downloading file in background thread
* */
#Override
protected String doInBackground(String... f_url) {
int count;
try {
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
InputStream input = new BufferedInputStream(url.openStream(), 8192);
// Output stream to write file
OutputStream output = new FileOutputStream("/sdcard/rss.xml");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress(""+(int)((total*100)/lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("Error: ", e.getMessage());
}
return null;
}
/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
pDialog.setProgress(Integer.parseInt(progress[0]));
}
/**
* After completing background task
* Dismiss the progress dialog
* **/
#Override
protected void onPostExecute(String file_url) {
// dismiss the dialog after the file was downloaded
dismissDialog(progress_bar_type);
Intent intent = new Intent(Loader.this,
LinkerNews.class);
startActivity(intent);
}
}
}
Or i can in next activity Load XML From Sd Card And Convert To0 String But how ???

Handling exception when trying to download file from url with async in android

I am using a AsyncTask to download a file from a URL in Android.
This is the class to download the file in the background:
//-----------------------------ASYNC DOWNLOADER--------------------------------
/**
* Background Async Task to download file
* */
class DownloadFileFromURL extends AsyncTask<String, String, String> {
/**
* Before starting background thread
* Show Progress Bar Dialog
* */
#SuppressWarnings("deprecation")
#Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(progress_bar_type);
}
//TODO Zustzinfos für alle Methoden hinzufügen
/**
* This method is called for executing the background task in the AsyncTask.
* For this tutorial we are only sleeping the thread for the number of
* seconds passed as parameter of the function.
*
* #param numSeconds: life of the task
* #return the result of the background task
*/
#Override
protected String doInBackground(String... f_url) {
int count;
try {
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
// getting file length
int lenghtOfFile = conection.getContentLength();
// input stream to read file - with 8k buffer
InputStream input = new BufferedInputStream(url.openStream(), 8192);
// Output stream to write file
OutputStream output = new FileOutputStream("/sdcard/"+Name+".xml");
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress(""+(int)((total*100)/lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("ASYNC",e.getMessage());
}
return null;
}
/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
pDialog.setProgress(Integer.parseInt(progress[0]));
}
/**
* After completing background task
* Dismiss the progress dialog
* **/
#SuppressWarnings("deprecation")
#Override
protected void onPostExecute(String error) {
// dismiss the dialog after the file was downloaded
dismissDialog(progress_bar_type);
String xmlPath = Environment.getExternalStorageDirectory().toString() + "/"+Name+".xml";
Log.d("XMLDOWNLOADPATH", xmlPath);
Log.d("DOWNLOADXML","End Download XML file");
}
}
I want to be able to recognize in my main activity (the async class is a inner class of the main acticity) if there was a exception and show the error message in a Dialog or Toast.
I tried to return the value from doInBackground() to onPostExecute() and write this String to a global String variable like this:
protected String doInBackground(String... f_url) {
String error = null;
try {
}
catch(Exception e){
error = e.toString();
}
return error;
#Override
protected void onPostExecute(String error) {
globalStringvariable = error;
}
But this does not work properly, the dialog does not always show the exception message. Is this the best way to realize my problem?

e.getMessage();
That's what you're looking for.
Also note that if your getting null, it can be because you are catching Exception as a generic, you should always try to catch a specific Exception in order to get the message back.