DownloadTask.java

package com.myPack.networkCalls;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.widget.Toast;

import com.myPack.UmahroConstants;
import com.myPack.utils.AppCallBackListner;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class DownloadTask {
    private static final String TAG = "Download Task";
    private Context context;

    private String downloadUrl = "", downloadFileName = "";
    private ProgressDialog progressDialog;
    AppCallBackListner.ResultListener listener;
    public DownloadTask(Context context, String downloadUrl, AppCallBackListner.ResultListener listener) {
        this.context = context;

        this.listener = listener;

        this.downloadUrl = downloadUrl;


        downloadFileName = downloadUrl.substring(downloadUrl.lastIndexOf('/')+1, downloadUrl.lastIndexOf('.')-1);//Create file name by picking download file name from URL
        Log.e(TAG, downloadFileName);

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

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

        File apkStorage = null;
        File outputFile = null;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressDialog = new ProgressDialog(context);
            progressDialog.setMessage("Downloading...");
            progressDialog.setCancelable(false);
            progressDialog.show();
        }

        @Override
        protected void onPostExecute(Void result) {
            try {
                if (apkStorage != null) {
                    listener.onClick(apkStorage);
                    Toast.makeText(context, "Document Downloaded Successfully", Toast.LENGTH_SHORT).show();
                } else {
                    Log.e(TAG, "Download Failed");

                }
            } catch (Exception e) {
                e.printStackTrace();

            }
            finally {
                progressDialog.dismiss();
            }
            super.onPostExecute(result);
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            try {
               URL url = new URL(downloadUrl);//Create Download URl
                HttpURLConnection c = (HttpURLConnection) url.openConnection();//Open Url Connection
                c.setRequestMethod("GET");//Set Request Method to "GET" since we are grtting data

                c.connect();//connect the URL Connection

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

                File myDir = new File(UmahroConstants.FILE_PATH);
                myDir.mkdirs();

                final String name = UmahroConstants.FILE_PATH + "/" +downloadFileName + ".pdf";
                apkStorage = new File(name);

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

                InputStream is = c.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
                }

                //Close all connection after doing task
                fos.close();
                is.close();
            } catch (Exception e) {
                progressDialog.dismiss();
                //Read exception if something went wrong
                e.printStackTrace();
                apkStorage = null;
                Log.e(TAG, "Download Error Exception " + e.getMessage());
            }
            return null;
        }
    }
}