Download any file from URL and save in storage with loader in notification

👉 AndroidManifest.xml :

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.INTERACT_ACROSS_USERS" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />


👉 DownloadSingleTask :

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Environment;
import android.os.Handler;
import android.support.v4.app.NotificationCompat;
import android.util.Log;
import android.widget.Toast;

import com.evoli.sanghvi.sanghvi.R;
import com.evoli.sanghvi.sanghvi.common.ServerSettings;
import com.evoli.sanghvi.sanghvi.interfaces.AsyncResponse;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Calendar;

public class DownloadSingleTask {

   private static final String TAG = "Download Task";
   public AsyncResponse delegate = null;
   private Context context;
   private String downloadUrl;

   public DownloadSingleTask(AsyncResponse asyncResponse, Context context, String downloadUrl) {
       this.context = context;
       this.downloadUrl = ServerSettings.Main_URL + downloadUrl;
       delegate = asyncResponse;

       //Start Downloading Task
       new DownloadSingleTask.DownloadingTask().execute();
   }

   private class DownloadingTask extends AsyncTask<String, Integer, Void> {

       private int PROGRESS_MAX = 100;
       private int PROGRESS_CURRENT = 0;
       private NotificationManager mNotificationManager;
       private NotificationCompat.Builder mBuilder;
       private int notificationID_;
       private File apkStorage = null;
       private File outputFile = null;

       @Override
       protected void onPreExecute() {
           super.onPreExecute();

           notificationID_ = Application_shangvi.NotificationID.getID();
           mBuilder = new NotificationCompat.Builder(context, "notify_001");

           mBuilder.setSmallIcon(android.R.drawable.stat_sys_download);
           mBuilder.setContentTitle(context.getResources().getString(R.string.downloadInProgress));
           mBuilder.setPriority(Notification.PRIORITY_MAX);
           mBuilder.setColor(context.getResources().getColor(R.color.colorLogo));
           mBuilder.setOnlyAlertOnce(true);
           mBuilder.setProgress(0, 0, true);
           mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

           if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
               NotificationChannel channel = new NotificationChannel("notify_001", "Channel human readable title", NotificationManager.IMPORTANCE_DEFAULT);
               mNotificationManager.createNotificationChannel(channel);
           }

       }

       @Override
       protected void onPostExecute(Void result) {
           try {
               mBuilder.setSmallIcon(android.R.drawable.stat_sys_download_done);
               if (outputFile != null) {
                   new Handler().postDelayed(new Runnable() {
                       @Override
                       public void run() {

                           mBuilder.setContentTitle(context.getResources().getString(R.string.downloadCompleted));
                           mBuilder.setProgress(0, 0, false);
                           mNotificationManager.notify(notificationID_, mBuilder.build());
                       }
                   }, 2000);
               } else {
                   new Handler().postDelayed(new Runnable() {
                       @Override
                       public void run() {
                           mBuilder.setContentTitle(context.getResources().getString(R.string.downloadAgain));
                           mBuilder.setProgress(0, 0, false);
                           mNotificationManager.notify(notificationID_, mBuilder.build());
                       }
                   }, 2000);
                   Log.e(TAG, "Download Failed");
               }
           } catch (Exception e) {
               e.printStackTrace();
               //Change button text if exception occurs
               new Handler().postDelayed(new Runnable() {
                   @Override
                   public void run() {
                       mBuilder.setContentTitle(context.getResources().getString(R.string.downloadAgain));
                       mBuilder.setProgress(0, 0, false);
                       mNotificationManager.notify(notificationID_, mBuilder.build());
                   }
               }, 2000);
               Log.e(TAG, "Download Failed with Exception - " + e.getLocalizedMessage());
           }

           try {
               delegate.processFinish(true);
           } catch (UnsupportedEncodingException e) {
               e.printStackTrace();
           }
           super.onPostExecute(result);
       }

       protected void onProgressUpdate(Integer... progress) {

           mBuilder.setProgress(PROGRESS_MAX, progress[0], true);
           // Displays the progress bar on notification
           mNotificationManager.notify(notificationID_, mBuilder.build());
       }

       @Override
       protected Void doInBackground(String... params) {
           try {

               Calendar calendar = Calendar.getInstance();
               String date = fromInt(calendar.get(Calendar.MONTH))
                       + fromInt(calendar.get(Calendar.DAY_OF_MONTH))
                       + fromInt(calendar.get(Calendar.YEAR))
                       + fromInt(calendar.get(Calendar.HOUR_OF_DAY))
                       + fromInt(calendar.get(Calendar.MINUTE))
                       + fromInt(calendar.get(Calendar.SECOND));


               String[] subFileName = downloadUrl.split("/");
               String downloadFileName = date.toString() + subFileName[subFileName.length - 1];
               Log.e(TAG, downloadUrl);
               Log.e(TAG, downloadFileName);

               URL url = new URL(downloadUrl);//Create Download URl
               HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();//Open Url Connection
               httpURLConnection.setRequestMethod("GET");//Set Request Method to "GET" since we are grtting data
               httpURLConnection.connect();//connect the URL Connection

               //If Connection response is not OK then show Logs
               if (httpURLConnection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                   Log.e(TAG, "Server returned HTTP " + httpURLConnection.getResponseCode()
                           + " " + httpURLConnection.getResponseMessage());
               }

               //Get File if SD card is present
               if (new CheckForSDCard().isSDCardPresent()) {
                   apkStorage = new File(Environment.getExternalStorageDirectory(), "/" + context.getResources().getString(R.string.app_name));
               } else
                   Toast.makeText(context, "Oops!! There is no SD Card.", Toast.LENGTH_SHORT).show();

               //If File is not present create directory
               if (!apkStorage.exists()) {
                   apkStorage.mkdir();
                   Log.e(TAG, "Directory Created.");
               }

               outputFile = new File(apkStorage, downloadFileName);//Create Output file in Main File

               //Create New File if not present
               if (!outputFile.exists()) {
                   outputFile.createNewFile();
                   Log.e(TAG, "File Created");
               }

               FileOutputStream fos = new FileOutputStream(outputFile);//Get OutputStream for NewFile Location

               InputStream is = httpURLConnection.getInputStream();//Get InputStream for connection

               byte[] buffer = new byte[1024];//Set buffer type
               int len1 = 0;//init length
               while ((len1 = is.read(buffer)) != -1) {
                   fos.write(buffer, 0, len1);//Write new file
                   publishProgress(Math.min(PROGRESS_CURRENT * 10, 100));
                   PROGRESS_CURRENT++;
               }
               //Close all connection after doing task
               fos.close();
               is.close();
               scanPhoto(context, outputFile.toString());

           } catch (Exception e) {
               //Read exception if something went wrong
               e.printStackTrace();
               outputFile = null;
               Log.e(TAG, "Download Error Exception " + e.getMessage());
           }
           return null;
       }
   }

public static String fromInt(int val) {
   return String.valueOf(val);
}

public static void scanPhoto(Context context, String imageFileName) {
   Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
   File f = new File(imageFileName);
   Uri contentUri = Uri.fromFile(f);
   mediaScanIntent.setData(contentUri);
   context.sendBroadcast(mediaScanIntent);
}
}

👉 Call this class :

ConnectivityManager cn = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo nf = cn.getActiveNetworkInfo();
if (nf != null && nf.isConnected()) {

       new DownloadSingleTask(new AsyncResponse() {
           @Override
           public void processFinish(Object output) throws UnsupportedEncodingException {

           }
       }, this, url);

} else {
   Toast.makeText(Activity_Main.this, getResources().getString(R.string.NoInternet), Toast.LENGTH_LONG).show();
}


👉 strings.xml :

<string name="NoInternet">No Internet connection</string>