Best libraries for Android Developers
Tags: android, developers
Published: 2022-07-16 06:48:31

Android libraries to help you with your app development. Some of them you may already know, but I am sure you can find a hidden gem among these! I have used some of these libraries here that have made development fun and easy for me.
There are hundreds of new libraries being developed every day, but very few can impress developers and prove potent

## What are Android libraries?
Libraries are major game changers in software development irrespective of platform or stack. With libraries, developers leverage the efforts of other developers to perform actions/functions faster, more effective, and with lesser boilerplate codes. In this article, we will look at various categories in Android development and the common libraries used in them.
These libraries for developers provide with basic pre-written codes and other important elements that can be used instantly rather than performing these tasks from scratch. 

Before we start, why don’t we take a moment and understand what Dependency Injector is?

## Dependency Injector Library
Dependency injection (DI) is a method that is broadly used in programming for Android development. One can create a good Android library architecture for apps by following the principles of DI.

You get the following benefits for using Android libraries for Dependency Injection: 

- Reusability of code
- Ease of testing 
- Ease of refactoring

Popular libraries used for DI are Hilt, Dagger2 and Koin.

###  [Hilt](https://github.com/googlecodelabs/android-hilt)
Hilt, famously known as the dependency injection library, helps decrease the boilerplate of performing manual dependency injection in your Android project. Performing manual dependency injection needs the construction of each class and its dependencies. Also, the containers will help to reuse and organize dependencies.

Hilt makes it easy to integrate Dagger dependency injection into Android apps. Hilt’s goals are to make Dagger-related infrastructure for Android apps easier to use. To make setup, readability/understanding, and code exchange between apps easier, a common set of components and scopes was created.

### [Koin](https://github.com/InsertKoinIO/koin)
Navigation is known as a framework to easily move between destinations within the Android app. Using Navigation Library makes it easier to create navigation in your Android app. However, it only works with an app that offers a proper API regardless of the destination implementation.

To utilize this component in your app, add Activities, Fragments, or other components as well. Add the Google Maven repository to add dependencies on Navigation.

### [Dagger](https://dagger.dev/)

We cannot complete the list without mentioning Dagger here. 
Dagger is a fully static, compile-time dependency injection framework for Java, Kotlin, and Android. It is an adaptation of an earlier version created by Square and now maintained by Google.

Dagger sets itself apart from other dependency injection libraries.  

The dependency injector library helps to provide smaller components to another model and helps them remain intact with each other.

While developing larger applications, it would be challenging to handle dependency injection. This time, Dagger will save you in this situation as it creates a dependency injection graph in compile-time via annotation processors.

## Networking Libraries
Here are the tools that you need for establishing any kind of network communication within the Android app.

### [Retrofit](https://github.com/square/retrofit)
Retrofit is a type-safe HTTP client for Android and Java – developed by Square.

Retrofit is the best library that lets you connect to HTTP-based API services from your Android applications. It leverages the [OkHttp](https://github.com/square/okhttp) library’s core functionality, adding a bunch of features to it while eliminating the boilerplate code.

One can effortlessly manipulate endpoints and headers, add a request body and query parameters, and select request methods – all with just annotations in Retrofit. Moreover, this Android library also takes care of parsing POJOs by using converters.

## Image Loading Libraries
Image loading libraries are a knight in shining armor combating the problem of “out memory errors” in Android apps caused by loading multiple images at a time. Let’s look at the best Android libraries options out there in this category.

### [Picasso](https://github.com/square/picasso)
Maintained by Square, Picasso is a trusted and widely used Android image library. Picasso claims to allow for hassle-free image loading in the application—often in one line of code. 

Some of the pitfalls that Picasso takes care of include handling ImageView recycling and downloading cancellation in an adapter, facilitating complex image transformations using minimal memory, automatic memory, and caching.

Additional features that makes Picasso a popular choice among Android app developers are –

Picasso automatically detects adapter re-use and the previously canceled download.
It easily and effectively transforms images to make them fit better into layouts and reduce memory size.
For more advanced effects, one can specify custom transformations.

### [Glide](https://github.com/bumptech/glide)
Glide is yet another praised image loader and one of the best new Android libraries for developers, managed by Bumptech. Not just this, but it is also recommended straight by Google.

Glide not only provides animated GIF support while handling image loading and caching but also helps in fetching, decoding, displaying video calls, images, and these GIFs. It also includes a flexible  API allowing developers and programmers to plug in any network stack, as its default stack is HttpUrlConnection.  

This library primarily aims at making the scrolling process for any list of images as smooth as it can be. More so, it is also effective in case you need to fetch, resize, or even display a remote image.

## Debugging libraries
Almost an indispensable step in the app development process, debugging an application before its final release is as important as it gets. For this purpose, let’s have a look at some useful libraries.

### [Stetho](https://github.com/facebook/stetho)
Stetho claims to be a “sophisticated debug bridge for Android applications”. The use of this library is not limited to just Network inspection, Database inspection, JavaScript Console, etc. but developers use it to have access to the Chrome Developer Tools features that are natively part of the Chrome desktop browser. Moreover, developers can choose to enable the optional dump app tool offering a powerful command-line interface to application internals.

### [Hyperlog-Android](https://github.com/hypertrack/hyperlog-android)
This is a standard Android Log class for storing logs in an Android database library and push them to a distant server for debugging. It is also a utility logger library.

This library provides end to end visibility and helps to debug issues. HyperTrack SDK pushes log to the Hyperlog server, and the server makes use of ELK stack to process the logs and visualize them on Kibana.

## Reactive Programming libraries
In Reactive programming, data is released from a component (a source if you will) to the other component known as Subscriber, assisting in handling asynchronous tasks efficiently. So in short, these libraries help with transferring data from source to subscribers. Some of the widely used Android app development libraries for this purpose are:

### [RxJava2](https://github.com/ReactiveX/RxJava)
If you are looking for a library that helps you in implementing reactive programming (create reactive applications), then RxJava is an ideal choice for you. It is officially described as “a library for composing asynchronous and event-based programs by using observable sequences”. 

This library is considered unbeatable by Android app developers because it simplifies the process to chain async operations, opens a more explicit way to declare how concurrent operations should work, is able to highlight errors sooner than other libraries, among other things

Observables are the data sources and they exist in various types: `Observer`, `Single`, `Flowable`, `Maybe`, and `Completable`. Each of these types has a unique use case which we can read more about [here](https://mindorks.com/course/demo/learn-rxjava/chapter/id/2).

### [RxAndroid](https://github.com/ReactiveX/RxAndroid)
RxAndroid, on the other hand, is an extension of RxJava2. It offers functionalities just peculiar to the Android platform, like the provision of a `Scheduler` that schedules on the main thread or any given ` Looper`.


## Drawing libraries

Here are some Android apps graphic libraries that have stood apart from the crowd. 

### [MPAndroidChart](https://github.com/PhilJay/MPAndroidChart)
MPAndroidChart is an impeccable Android chart/graph view library. It supports radar, line, bar, bubble, pie, candlestick charts along with scaling, animations, and panning.

If you are looking for its iOS counterpart then, Charts is the one for iOS app development.

### [Holo Graph library](https://github.com/Androguide/HoloGraphLibrary)
It is another new graphic library which is continuously becoming a favorite of many Android app development companies. This library is ideal for adding impeccably designed graphs and charts into Android applications. It includes: 

- LineGraph view (which looks something like this) –
- BarGraph View
- PieGraph View
- MultiSeriesDonutGraph View

### [AnimatedPieView](https://github.com/razerdp/AnimatedPieView)
AnimatedPieView is another method for showing pie charts and ring graphs on Android.

This library offers various benefits like: alpha animation on touch, fitting text field position itself during an animation, transformation between a pie diagram and a ring chart, animation while drawing charts and so on.

### [MyLittleCanvas](https://github.com/florent37/MyLittleCanvas)
It is one of the top libraries for Android developers. This Android Library is used to achieve features such as custom underline on a `TextView`. It is also used to apply Textshape, lineshape, etc. with canvas methods. If you don't know how to use Canvas, use MyLittleCanvas instead!

## Testing libraries
In scaling up your skills as an android developer, you need to learn how to test your code. Writing tests as you code is one of the best practices in android development. Testing your project shows the competence and efficacy of your mobile app. You can use these libraries to test your mobile app before you ship it to the market.


### Espresso
A part of the Android testing support library, Espresso is evidently a test framework that enables developers to build user interface tests for Android applications. Implying that this library lets you write tests and check whether the text of a TextView is similar to another text or not. It imparts the impression of a real user using the app while it is running on  both real device and emulators.
To use this library, you are required to add dependencies to the app module `build.gradle` file.
Once you have done this, you can set the instrumentation runner and sync the Gradle files, followed by creating a test file. This is the reason why businesses prefer Android app bundles.

### [Mockito](https://github.com/mockito/mockito)

Most times, the classes we intend to write tests for depend on other classes. Configuring these classes just for this purpose can be hectic. This is where Mockito comes in. It is a mocking framework that helps us create and configure mock (fake) objects. It is usually used with together with JUnit.

### [Robolectric](https://github.com/robolectric/robolectric)
Robolectric is another unparalleled unit testing library. What this library does is that it handles inflation of resource loading, views, including other things. It makes the tests created in the library more efficacious and potent in performing functions that real devices with Android framework dependencies perform. In a sense, Robolectric simulates the Android SDK for the tests, eliminating the need for additional mocking frameworks like Mockito.

Now again, you need to add the dependency in your app’s build.gradle file, followed by creating a sample test class . 

These Android libraries list have made it to this record based on the popular recommendation of the Android developers. Their features, functions, and performance together emit excellence in their niche of purpose.

## Database Helper Library

Offline data persistence is very important to enhance user experience. We usually need our applications to store important information that will be required on a next startup of the app or to make data available when no internet connection is available. As storing data is more complex than just combining key and value pairs, numerous libraries have been created to make storing this task easier in Android. In this section, we will look at one great persistence library: Room.


### [Room](https://developer.android.com/jetpack/androidx/releases/room?gclid=Cj0KCQjwlK-WBhDjARIsAO2sErSBy1x720SEkwTM43Ek6zkSKYTZhdx-p0_XS38r3cAQRT6P_Fr-q8caAoVuEALw_wcB&gclsrc=aw.ds)
Room is a persistence library which is part of the Android Architecture Components. Room provides local data persistence with minimal boilerplate code. It provides an abstraction layer over SQLite, thereby making it easier to work with databases in our app. This library comes with a lot of advantages such as verifying SQL queries at compile time, rejecting database queries on the main thread (except when explicitly stated while initializing the database), providing implementation best practices, etc.

Room is composed of three main components: the Database, the DAO (Data Access Objects), and Entities. Each of them is co-related in order to make the library functional. The Entity class represents a database table and has to be annotated with `@Entity`. The variables in the class represent the columns the table will have. The DAO is an interface that contains the methods used for accessing the database. Room uses the interface to generate an implementation class for us.

There are four specific annotations for the basic DAO operations: `@Insert`, `@Update`, `@Delete`, and `@Query`. Then, we have the Database class. This is an abstract class annotated with `@Database` and that extends RoomDatabase. This class defines the list of entities and their DAOs to be used.

### [Obectbox](https://github.com/objectbox/objectbox-java)
Object Box is a widely used Android databinding library that allows you to devote your valuable time to Various USPs of the product instead of storing and retrieving data. This library acts as an object oriented embedded database considered as a right alternative for SQLite. Since its documentations and portfolio are well defined, it is a perfect suit for IoT (Internet of Things) apps.

## Custom Fonts Library

Almost every Android developer is passionate about the look and feel of their app. Sometimes we might need to go the extra mile into choosing a unique font for the app to give it the same feel across all devices. In situations like this, there are some libraries that can help us to use a custom font for all our texts in the app.


### [Calligraphy](https://github.com/chrisjenx/Calligraphy)
Calligraphy is one of the most popular custom font libraries available and it is quite easy to get along with. With this library, we can easily declare a single font across our whole application or define fonts individually to a text.

## View Binding Libraries
The need for view binding libraries first surfaced when the need to reduce the boilerplate code when assigning views to variables arose. As a matter of fact, the number of Android support libraries worth mentioning for this purpose is numbered and two of the most prominent of them are:

### [Android View Binding](https://developer.android.com/topic/libraries/view-binding)
View binding is a feature that allows you to more easily write code that interacts with views. Once view binding is enabled in a module, it generates a binding class for each XML layout file present in that module. An instance of a binding class contains direct references to all views that have an ID in the corresponding layout.

In most cases, view binding replaces `findViewById`.


### [Android Data Binding](https://developer.android.com/topic/libraries/data-binding)
The Data Binding Library is a support library that allows you to bind UI components in your layouts to data sources in your app using a declarative format rather than programmatically.

Layouts are often defined in activities with code that calls UI framework methods. 

Binding components in the layout file lets you remove many UI framework calls in your activities, making them simpler and easier to maintain. This can also improve your app's performance and help prevent memory leaks and null pointer exceptions.


## Scanning Libraries
In order to integrate scanning features while developing custom Android apps and increase their functionality level, developers prefer the below-mentioned libraries.

### [Zxing](https://github.com/journeyapps/zxing-android-embedded)
Acronym for ‘Zebra Crossing’, ZXing is a barcode image-processing Android library that is implemented in Java, with ports to other programming languages. This library also has support for the 1D product, 1D industrial, and 2D barcodes.

Google also uses ZXing in order to make millions of barcodes indexable on the web.  It also forms the basis of Android’s Barcode Scanner app and is integrated into Google Book Search and Google Product.

### [CAMView](https://github.com/LivotovLabs/CamView)
This is an effective alternative to the ZXing barcode scanner. It is an Android camera easy access library with an embedded QR scanner which is based on ZXing. 

CamView library possesses a set of components (views in simple words) which are set to be put to your layout files, allowing developers and giving immediate access to-

- Live preview video feed from the device camera
- Scanning barcodes with the help of ZXing’s built-in decoding engine
- To perform your own camera live data processing


## Image Cropper
Tools used in cropping images and also adding some styling to the image.

### [CanHub](https://github.com/CanHub/Android-Image-Cropper)
CanHub is a powerful tool used to zoom and rotate the image from the camera or gallery. The image cropped can be customized in shape, limits and style. It is a project forked from [ArthurHub](https://github.com/ArthurHub/Android-Image-Cropper).

## [Android Jetpack](https://developer.android.com/jetpack)

Android Jetpack is a suite of libraries to help developers follow best practices, reduce boilerplate code, and write code that works consistently across Android versions and devices so that developers can focus on the code they care about. Some libraries like Room, View binding and Data Binding are part of Android jetpack. Other libraries are [WorkManager](https://developer.android.com/topic/libraries/architecture/workmanager), [Navigation](https://developer.android.com/guide/navigation/navigation-getting-started), [CameraX](https://developer.android.com/training/camerax).

Jetpack libraries are published in the `androidx` namespace.

## Conclusion
These libraries/tools significantly reduce the amount of boilerplate code written to perform various functions while developing for Android. Knowing the best libraries can help us improve the quality of our apps and make us produce more in less time.

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