Downloading Bulk Images in Android

Hello Android Geeks,

Recently, I got an Android app project in my current work, Wherein the App needs to download bulk images via Webservices/API,
and the requirement of the process of downloading the assets is must be synchronous.

Here's is the sample code that I made to showcase the Android Library of NOSTRA13
entitle "Android-Universal-Image-Loader". for more info about this visit his GITHUB REPO

1.Download and compile the UIL in the Gradle's dependency

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.2.0'
}

2.Setup your Android Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sample.xeugene.imagedownload" >

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

    <application
        android:name=".App"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

3. MainActivity

package com.sample.xeugene.imagedownload;

import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import com.nostra13.universalimageloader.core.ImageLoader;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    final static String TAG = "MAIN_ACTIVITY";
    ImageLoader imageLoader;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageLoader = ImageLoader.getInstance();

        new DownloadThisImageFromUrl().execute();

    }
    //Running the method imageloader.loadImagesync() must be
    // run in the background thread of the App.
    public class DownloadThisImageFromUrl extends AsyncTask<String, String ,String> {
        @Override
        protected String doInBackground(String... strings) {
            for(String urls : listOfUrls()) {
                Bitmap image = imageLoader.loadImageSync(urls);
                Log.d(TAG, "Download Success: " + image);
                //You can use this var image to save in your SQLite DB :)
            }
            return null;
        }
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Log.d(TAG, "DOWNLOAD COMPLETE!");
        }
    }

    //Static list url of the Images
    //You can add your desired Images here :)
    public List<String> listOfUrls(){
        List<String> listUrl = new ArrayList<>();
        listUrl.add("http://dogzone.tcwebsites.netdna-cdn.com/wp-content/uploads/2015/01/Funny-dog-names.jpg");
        listUrl.add("http://dreamatico.com/data_images/dog/dog-5.jpg");
        listUrl.add("http://static.communitytable.parade.com/wp-content/uploads/2014/02/labrador-america-top-dog-breed-ftr.jpg");
        return  listUrl;
    }
}

4. Instantiate the Universal Image Loader library in the Application (Singleton)

package com.sample.xeugene.imagedownload;

import android.app.Application;
import android.content.Context;

import com.nostra13.universalimageloader.cache.memory.impl.WeakMemoryCache;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;
import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;

/**
 * Created by EugeneAllen on 9/22/2015.
 */
public class App extends Application {


    @Override
    public void onCreate() {
        super.onCreate();

        initImageLoader(getApplicationContext());
    }

    public static void initImageLoader(Context context) {
        DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
                .cacheOnDisc(true).cacheInMemory(true)
                .imageScaleType(ImageScaleType.EXACTLY)
                .displayer(new FadeInBitmapDisplayer(300)).build();

        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(
                context)
                .defaultDisplayImageOptions(defaultOptions)
                .memoryCache(new WeakMemoryCache())
                .discCacheSize(100 * 1024 * 1024).build();

        ImageLoader.getInstance().init(config);
    }
}