Android Basics Library

This library offers some barebone code for android common to most applications. It provides simple classes and pre-written functions for - internet access, shared preferences storage and retrieval, image picker and bitmap operations, file read and write, recycler view, image downloading and quick database support

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Android Basics Library

This library offers some barebone code for android common to most applications. It provides simple classes and pre-written functions for:


Android Arsenal

The library is on Jcenter, so usage is really simple. Add the following dependency in your app’s build.gradle:

dependencies {
    compile 'com.github.bijoysingh:android-basics:1.1'

You might need to also include these in case you use the corresponding dependencies

dependencies {
    // For Image Downloader
    compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.4'
    // For internet access
    compile 'com.mcxiaoke.volley:library:1.0.17'
    // For Timestamp utility
    compile 'net.danlew:android.joda:2.8.1'
    // For basic features from Google
    compile ''
    compile ''
    // For Recycler View
    compile ''

Checkout on Android Arsenal

Basic Usage

Internet Access

Internet access is simpler than ever. I have added a simple DefaultQueryExecutor class for convenient usage.

DefaultQueryExecutor executor = new DefaultQueryExecutor.Builder(context)
    .setOnQueryListener(queryListener) // optional
    .setAuthenticationProvider(authenticationProvider) // optional
    .setTimeout(DefaultRetryPolicy.DEFAULT_TIMEOUT_MS) // optional
    .setMaxRetries() // optional
    .setRetryBackoffMultiplier() // optional

You can create a OnQueryListener object or have the activity making the request implement it.

QueryParams query = QueryParams.Builder(url)
    .setCache(cacheFilename) // optional: the filename you want to save the result to as a cache
    .setQueryIdentifier(queryId) // optional
    .setAuthenticated(isAuthenticated) // optional: tells if you want to use the genAuthenticationData method of the AuthenticationProvider
    .setMethod(Request.Method.POST) // optional
    .setExtra(extraHashMap) // optional
    .addExtra(key, value) // optional

Making a query is really simple too

executor.send(query, data);

Extend the QueryExecutor class for more control on your queries and for supporting more things.

public class MyQeuryExecutor extends MyQeuryExecutor {

SharedPreferences storage and retrieval

Use the class and built in functions using put and get.

PreferenceManager preferences = new PreferenceManager(context);
preferences.put(KEY, your_variable);
preferences.get(KEY, your_default_variable);

Optionally Extend the PreferenceManager class.

public class Preferences extends PreferenceManager {
    public String getPreferencesFolder() {


If you plan to use SharedPreferences in Services due to recent changes in Android SharedPreferences this may not be your best option. You can go for a solution of use the library 'net.grandcentrix.tray:tray:0.11.1' But I have recently seen that it has bugs like deletion during updates. Try the new class StorageManager described next:

Async safe Storage Preferences (Experimental)

Use this class for saving/ retrieving content using put and get. You can get the content from services / main system alike. The access will be fast and will be the same.

StorageManager storage = new StorageManager(context);
storage.setIsAsync(true); // optional -> speeds up writes, does not affect the reading consistencies due to caching.

storage.put(KEY, your_variable);
storage.get(KEY, your_default_variable);

ImagePicker and Bitmap operations

ImageManager imageManager = new ImageManager();

Handle the response for this using handleResponse in onActivityResult

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Bitmap bmp = imageManager.handleResponse(requestCode, resultCode, data);

You can perform a number of Bitmap operations

ImageManager.getScaledBitmap(bitmap, scale);
ImageManager.resizeBitmap(bitmap, width, height)
ImageManager.getScaledBitmapWithHeight(bitmap, height);
ImageManager.getScaledBitmapWithWidth(bitmap, width);

File read and write

To store and retreive some text, some basic support code is available. This is needed if you want to save some file/ json you receive from the server to act as cache.

FileManager.write(context, filename, text_to_write);
String textRead =, filename);

Asynchronous write is now supported (I will be updated the way to access these functions to ease usage)

FileManager.writeAsync(context, filename, text_to_write);

Image Downloading

This library uses the Universal Image Loader library. To use this some basic configuration is pre-built. You can do this as follows

ImageLoaderManager.displayImage(context, image_url, image_view);


ImageLoaderManager loader = new ImageLoaderManager(context);
loader.displayImage(image_url, image_view);

You can also customize the image loader using

ImageLoader imageLoader = ImageLoaderManager.getImageLoader(context);
ImageLoader imageLoader = ImageLoaderManager.getImageLoader(context, diskCacheInMB, memoryCacheInMB);

and use it as follows:

ImageAware imageAware = new ImageViewAware(image_view, false);
imageLoader.displayImage(image_link, imageAware);

Some other useful functions

These are some common useful functions. These will expand with time.

DimensionManager.dpToPixels(context, dp);
DimensionManager.pixelsToDp(context, pixels);


I know toasts are pretty simple to use in Android. But I personally got pissed with typing the Toast.LENGTH_SHORT and a show() everytime. So I built a simple wrapper around it to reduce this boilerplate code. Using a ToastHelper static methods, R.string.your_toast_message);, "your toast message");

Using a ToastHelper object

ToastHelper toastHelper = new ToastHelper(context);"your toast method");;
toastHelper.showLong("your toast method");

Locale String Format Wrappers

LocaleManager.toString(Character/Float/Double/Integer/Boolean variable);
LocaleManager.toString(Float/Double variable, precision);

This function will convert your variable to the String to these using the Locale. This functions is a wrapper around the code String.format. The function will prevent Lint Warning for the same.

Recycler View

Simple Recycler View

This is a recycler view with a simple one kind of view item. Extend the Recycler View Holder -> This is the holder for the view contents of one item. We will show you how to use this for a simple item

 * @example
 * View Item inside a layout R.layout.content_item
 *  ------------------------------------
 * |   TextView                         |
 * |   id -> content                    |
 *  ------------------------------------
public class YourViewHolder extends RecyclerViewHolder<YourItem> {

     * @example
     * TextView content;

    public YourViewHolder(Context context, View itemView) {
      super(context, itemView);
       * @example
       * content = (TextView) itemView.findViewById(;
    public void populate(YourItem data, Bundle bundle) {
        // Populate your view. You can set on click listeners etc.
         * @example
         * content.setText(data.getContent());

Extend the Recycler View Adapter, this is the controller to your recycler view. Most of the basic functions have already been done for you.

public class YourAdapter extends RecyclerViewAdapter<YourItem, YourViewHolder> {

   * The recycler view adapter constructor
   * @param context the application/activity context
  public YourAdapter(Context context) {
    super(context, R.layout.your_layout_file, YourViewHolder.class);
// Using this adapter is easy
YourAdapter yourAdapter = new YourAdapter(context);

// You can do a lot from this adapter. This will take your list of items
yourAdapter.addItem(item, position);

// You can get the default layout manager as well from the adapter.
// A layout manager controls the way your recycler view is rendered.
// This is basically like a simple list - LinearLayoutManager or
// a grid layout - GridLayoutManager

Setup your recycler view You could either do the following

    recyclerView = new RecyclerViewBuilder(context)
        .setView(activity, // or use this
        .setRecyclerView(recyclerView) // or use this
        .setOnScrollListener(onScrollListener) // optional
        .setLayoutManager(layoutManager) // set the layout manager

or the usual way will also work of course.

Multi View Recycler View

A common use case for recycler views is to use it with multiple view holders / views. This involves some common setup which has been taken care for you here.

public class YourAdapter extends MultiRecyclerViewAdapter<YourItem> {
  public YourAdapter(
    Context context,
    List<MultiRecyclerViewControllerItem<YourItem>> items) {
    super(context, items);

  public int getItemViewType(int position) {
    // Return an int value indicating your view type for the given position
// To set this up, you need to create this list of MultiRecyclerViewControllerItem items
// Each of these items maps, view type to some common properties like:
MultiRecyclerViewControllerItem<YourItem> item = new MultiRecyclerViewControllerItem.Builder<YourItem>()
    .viewType(VIEW_TYPE) // the view type for this view holder
    .spanSize(VIEW_SPAN) // optional for grid view: the number of columns the view spans
    .layoutFile(R.layout.your_view_item) // the view item layout for this view type
    .holderClass(YourRecyclerViewHolder.class) // the class of the holder

// You can create a list of these items for each view, and set it to the adapter constructor.
YourAdapter adapter = new YourAdapter(context, items);

// Optional for grid views: using this handles the span size properties for you.


Another common action you need to do is convert your timestamp string to time. And also convert it to the write timezone.

String timestamp = "...." // your timestamp string
TimestampItem item = new TimestampItem.Builder(timestamp)
    .setTimezone(hours, minutes) // optional
    .setDeviceTimezone() // optional
    .setTimeFormat("hh:mm aa") // optional
    .setDateFormat("dd MMMM yyyy") // optional
    .setDateTimeFormat("hh:mm aa, dd MMMM yyyy") // optional
item.getTime(); // the time string
item.getDate(); // the date string
item.getDateTime() // the date and time string
item.getCompressedDateTime(); // the compressed date and time


If you have to repeatted format your Dates here is a simple wrapper on your code

// Get Today's formatted date

// Get any Date's formatted date
DateFormatter.getDate("dd mmmm yyyy", date);
DateFormatter.getDate(date, locale);
DateFormatter.getDate("hh:MM a, dd mmmm yyyy", date, locale);

// Some default formats exist (a lot more exist)

Threading and Async

Hate writting a lot boilerplate code to use Executors or AsyncTasks, we got you covered

// Want to run something in background and handle it in UI thread
SimpleAsyncTask<String> task = new SimpleAsyncTask<>() { ... }

// Want to run something huge, with high priority, but in background
// Simply run something in the background

// Or get more control
SimpleThreadExecutor executor = new SimpleThreadExecutor();
List<String> names = ...;
Parallel<String, Integer> parallel = new Parallel();
parallel.setListener(new ParallelExecutionListener<String, Integer>() {

// Or get more control
SimpleThreadExecutor executor = new SimpleThreadExecutor();


Handling your permissions for Marshmallow made simpler, and cleaner

// Could be more than one permissions here
String[] permissions = new String[]{Manifest.permission.ACCESS_FINE_LOCATION};

// Initialise the manager object, with required permissions
PermissionManager manager = new PermissionManager(context, permissions);

 * Or set them as you need them
 * PermissionManager manager = new PermissionManager(context);
 * manager.setPermissions(permissions);

Now checking for permission is really simple


And requesting for permissions too

// Using an access code fixed in the library

// Using a custom access code, for more control

It will automatically detect which permissions are already allowed, and will request the missing permissions. To handle a response, the procedure is same as that in the usual case. You override the onRequestPermissionsResult listener.

Text Utils

Some common actions which need to be done with Text is now part of the library

To share a text to other applications on the device

new TextUtils.ShareBuilder(context)
  .setChooserText("Share using...") // Optional
// To copy text to a clipboard
TextUtils.copyToClipboard(context, textToCopy);

// To check if a string is null or empty

View Pager Activity and Fragment

There is a lot of boiler plate code which needs to be done for view pagers. This will save that for you

public class YourActivity extends SimpleViewPagerActivity {

  protected Fragment getPageFragment(int position) { ... }

  protected void onPageChanged(int position) { ... }

  protected int getPagesCount() { ... }

  protected int getViewPagerResourceId() {
public class YourFragment extends SimpleFragment {
  protected int getLayoutId() {
    return R.layout.your_fragment_layout;

  protected void onCreateView() {
    // Simply use like a activity
    TextView yourTextView = (TextView) findViewById(;

Random Helper

Sometimes you need to generate secure random numbers like IDs etc which are alphanumeric etc.

// Get a alpha numeric random string of length 16

// Get a alpha numeric random string of a fixed length

// Get a Big Integer which has upto a fixed approx length (this is because we use nearest power of 2)

Database Support

Adding database setup is super simple. You have to do very little work!

Just add a simple model like

public class YourDatabaseItem extends DatabaseModel {
    @DBColumn(primaryKey = true, autoIncrement = true)
    public Integer id;

    public String title;

    public String description;

Using @DBColumn you can add custom arguments like

fieldType = DBColumn.Type.INTEGER
unique = True
primaryKey = true, autoIncrement = true
fieldName = "custom_field_name"

You can create a custom class for your databases, or you can simply use the default database:

DatabaseManager db = new DatabaseManager(this, new DatabaseModel[]{new YourDatabaseItem()});

// To add an item
YourDatabaseItem your_item = ...;

// To get all items for a custom class
List<YourDatabaseItem> items = db.get(YourDatabaseItem.class);

A full fledged example can be seen in my TutorialApp.

Database Support (Alternate)

We have a custom Database support which does not use the SQLlite DB but uses a file and JSON. This let’s you have more control, like caching, update policy, etc.

public class ExampleDatabase extends SimpleDatabase<ExampleModel> {

  private static List<MedicineStorageModel> cache;

  public ExampleDatabase(Context context) {

  protected String getDatabaseFilename() {
    return "database.txt";

  protected void setCacheList(List<ExampleModel> list) {
    cache = list;

  protected List<ExampleModel> getCacheList() {
    return cache;

  protected String getId(ExampleModel object) {
    // Get a unique object id
    return object.getId();

  protected JSONObject serialise(ExampleModel object) {
    // This is the function which gets the JSONObject from a ExampleModel
    return null;

  protected ExampleModel deSerialise(JSONObject serialised) {
    // This is the function which gets the ExampleModel from a JSONObject
    return null;

  protected int compareModels(ExampleModel model1, ExampleModel model2) {
    // Optional comparison function, the output of getAll is ordered by this rule
    return 0;


JSON Parsing

Making a JSON Parser is simple to work

public class YourItem extends JsonModel { 
    public Integer integer_field;
    @JsonField(field = "alternate_json_field_name") 
    public String string_field;
    public Double real_field;
    @JsonField(field = Type.BOOLEAN)
    public Boolean boolean_field;
    @JsonField(field = Type.JSON)
    public JSONObject json_field;

The method automatically detects the type of the JSON field, you can still choose to override it. Further, it assumes that the name of the field is the JSON field, you can yet again choose to override it

You can also, quickly serialize your item into a JSON Object

JSONObject json = item.serialize();


Copyright 2016 Bijoy Singh Kochar

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.

Reference Licensing


Apache 2.0 License
Copyright (C) 2014,2015,2016 Xiaoke Zhang
Copyright (C) 2011 The Android Open Source Project


Apache 2.0 License

Universal Image Loader

Apache 2.0 License
Copyright 2011-2015 Sergey Tarasevich