public class DownloadService extends IntentService
{
public static final int NOTIFY_ID = 108;
NotificationCompat.Builder builder;
NotificationManagerCompat notificationManager;
boolean isProgress;
public DownloadService()
{
    super("DownloadService");
}

@Override
protected void onHandleIntent(Intent intent)
{
    String urlToDownload = intent.getStringExtra("url");
    String fileName = intent.getStringExtra("fileName");
    try
    {
        URL url = new URL(urlToDownload);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.connect();
        int fileLength = connection.getContentLength();
        InputStream input = new BufferedInputStream(connection.getInputStream());
        OutputStream output = new FileOutputStream(Environment.getExternalStorageDirectory() + "/" + Environment.DIRECTORY_DOWNLOADS + "/" + fileName);

        byte data[] = new byte[1024];
        long total = 0;
        int count;
        showNotification(fileName, 0);
        int progress = 0;
        while ((count = input.read(data)) != -1)
        {
            total += count;
            int newProgress = (int) total * 100 / fileLength;
            if(newProgress >= progress + 20){
            progress = newProgress;
            showNotification(fileName, progress);
            }
            output.write(data, 0, count);
        }
        output.flush();
        output.close();
        input.close();
    }
    catch (IOException e)
    {

    }
    finally{

    }
}

public void showNotification(String fileName, int progress)
{
    builder = new NotificationCompat.Builder(this);
    builder.setTicker("Загрузка");
    builder.setContentTitle(fileName);
    if(progress >= 100){
        builder.setSmallIcon(R.drawable.done);
        builder.setContentText("Загрузка завершена");
    }
    else{
    builder.setSmallIcon(android.R.drawable.stat_sys_download);
    builder.setProgress(100, progress, false);
    }
    Notification notification = builder.build();

    notificationManager = NotificationManagerCompat.from(this);
    notificationManager.notify(NOTIFY_ID, notification);}
}