Redesigning Android Development: Using Reactive Programming to Retrofit REST APIs and Concurrency

In this paper the current techniques and tools used by developers to create applications are described in detail and the use of REST APIs in Android applications as a case study. The first component is the installation of the APIs, which we will focus on the Retrofit library for network management, and the API Clients to manage requests. This study evaluates the nuances of JSON parsing, serialization, and deserialization through the Retrofit API client. We study the technique of data searching, the introduction of Tap Drawer using Firebase to improve the app functionality, and the string transformation method of Scalar with JSON Converter Factory.The tutorial explains how to set up an API, design an interface for Product ID query, use a Binding Adaptor for handling images and a Glide dependency to load images. As well, we consider how to create a Product Adaptor for a Recycler View which leverages Fragments to implement complex user interfaces. According to the plan of Android development, we absorb width, wrap content and verticality alignment as layout factors.The building of the “Adapter List” based on the “Create View Holder” function and the creation of Product Model class — which consists of fields for ratings and product details — as well as the JSON integration are presented in the article. Asynchronous processes are applied in the application as well as the `enqueue` technique has been used to provide effective network connection.We intend to acquire an experimental data by app scanning on the Android platform, by referring to Stack Overflow's most favourite pages and through a survey of mobile application developers in order to build a code collection associated with REST mobile client technologies. From our findings it follows that application communicating through the Internet phenomenon associated with JSON syntax implementation in comparison to XML data processing execution rather widespread and acceptable in terms of Android developers. We include the HTTP libraries standardized by third-party organizations in the paper which also explains how to use the practices.In unity, we discuss the perks of Android system uniqueness which facilitates the application customization, suppliers and the consumers, in terms of security, usability, and usefulness. Our app framework for Android offers coronary adjust to existing apps through behaviour simply without accessing or modifying app source code but sticks to the universal app-agnostic transformation objectives. This architecture is thus designed to allow the modified software version to function without any hindrance on any normal Android device. Keywords- REST API, Android, Retrofit, Firebase, Gson, Recycler View, JSON parsing, HTTP libraries, refactoring, Android programming principles.