Android - Kotlin

Introduction: Reactive Programming is a programming paradigm that’s concerned with data streams and propagation of change. The reactive model listens to changes in the event and runs the relevant code accordingly. RxJava is a Java based implementation of Reactive Programming. Whereas, RxAndroid is specific to Android platform which utilises some classes on top of the RxJava library. Classes and Concepts: There are 3 main components in RxJava. (i) Observable - It emits a stream of data or events. i.e., a class that can be used to perform some action, and publish the result. (ii) Observer - It receivers the events or data and acts upon it. i.e. a class that waits and watches the Observable, and reacts whenever the Observable publishes results. It have 4 interface methods to know the different states of Observable, as follows:         onSubscribe() - invoked when the Observer is subscribed.         onNext() - invoked when the new item is emitted from Observer.