Download using DownloadManager

The class android.app.DownloadManager (Since: API Level 9) is a system service that handles long-running HTTP downloads. Clients may request that a URI be downloaded to a particular destination file. The download manager will conduct the download in the background, taking care of HTTP interactions and retrying downloads after failures or across connectivity changes and system reboots.

It's a basic code to download file from internet using DownloadManager.

package com.AndroidDownload;

import java.io.FileInputStream;
import java.io.FileNotFoundException;

import android.app.Activity;
import android.app.DownloadManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AndroidDownloadActivity extends Activity {
 
 String Download_path = "http://goo.gl/Mfyya";
 String Download_ID = "DOWNLOAD_ID";
 
 SharedPreferences preferenceManager;
 DownloadManager downloadManager;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       preferenceManager = PreferenceManager.getDefaultSharedPreferences(this);
       downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
      
       Button btnDownload = (Button)findViewById(R.id.download);
       btnDownload.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    Uri Download_Uri = Uri.parse(Download_path);
    DownloadManager.Request request = new DownloadManager.Request(Download_Uri);
    long download_id = downloadManager.enqueue(request);
    
    //Save the download id
    Editor PrefEdit = preferenceManager.edit();
    PrefEdit.putLong(Download_ID, download_id);
    PrefEdit.commit();
   }});
   }
  
 @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  
  IntentFilter intentFilter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
  registerReceiver(downloadReceiver, intentFilter);
 }

 @Override
 protected void onPause() {
  // TODO Auto-generated method stub
  super.onPause();
  
  unregisterReceiver(downloadReceiver);
 }

 private BroadcastReceiver downloadReceiver = new BroadcastReceiver() {

  @Override
  public void onReceive(Context arg0, Intent arg1) {
   // TODO Auto-generated method stub
   DownloadManager.Query query = new DownloadManager.Query();
   query.setFilterById(preferenceManager.getLong(Download_ID, 0));
   Cursor cursor = downloadManager.query(query);
   
   if(cursor.moveToFirst()){
    int columnIndex = cursor.getColumnIndex(DownloadManager.COLUMN_STATUS);
    int status = cursor.getInt(columnIndex);
    int columnReason = cursor.getColumnIndex(DownloadManager.COLUMN_REASON);
    int reason = cursor.getInt(columnReason);
    
    if(status == DownloadManager.STATUS_SUCCESSFUL){
     //Retrieve the saved download id
     long downloadID = preferenceManager.getLong(Download_ID, 0);
     
     ParcelFileDescriptor file;
     try {
      file = downloadManager.openDownloadedFile(downloadID);
      Toast.makeText(AndroidDownloadActivity.this,
        "File Downloaded: " + file.toString(),
        Toast.LENGTH_LONG).show();
     } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      Toast.makeText(AndroidDownloadActivity.this,
        e.toString(),
        Toast.LENGTH_LONG).show();
     }
     
    }else if(status == DownloadManager.STATUS_FAILED){
     Toast.makeText(AndroidDownloadActivity.this,
       "FAILED!\n" + "reason of " + reason,
       Toast.LENGTH_LONG).show();
    }else if(status == DownloadManager.STATUS_PAUSED){
     Toast.makeText(AndroidDownloadActivity.this,
       "PAUSED!\n" + "reason of " + reason,
       Toast.LENGTH_LONG).show();
    }else if(status == DownloadManager.STATUS_PENDING){
     Toast.makeText(AndroidDownloadActivity.this,
       "PENDING!",
       Toast.LENGTH_LONG).show();
    }else if(status == DownloadManager.STATUS_RUNNING){
     Toast.makeText(AndroidDownloadActivity.this,
       "RUNNING!",
       Toast.LENGTH_LONG).show();
    }
   }
  }
  
 };

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:orientation="vertical" >

   <TextView
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:text="@string/hello" />
   <Button
       android:id="@+id/download"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:text="Start Download" />

</LinearLayout>

remark: "android.permission.INTERNET" is needed in AndroidManifest.xml.