RxUIKotlin

Android UI + Kotlin + RxJava3

Made with love at the Equisense HQ. This library is used in our Equisense app since a few years.

Introduction

This library is made to manage your subscriptions when fetching data with RxJava3 inside a Activity, a Fragment or a ViewHolder. It cancel your request depending of the state of the lifecycle by disposing your subscription (calling dispose() on the Disposable object returned by the subscribe methods).

RxUIKotlin is lightweight, the .aar file weights less than 50kb and it only require a few dependencies: appcompat, recyclerview, rxjava and rxandroid. RxUIKotlin will never change the behavior of your chaning, it only dipose it when you want to.

RxUIKotlin is splitted into 2 separates artifacts, the core, which is explained here, and the fragmentmanager. fragmentmanager helps you to listen fragment events, adding or removing from a FragmentManager. You can use fragmentmanager without core, both are independent.

Unlike RxLifecycle, this library doesn't transform your observable by emitting onComplete() when your view is gone, it just dispose() your Disposable, that's all. So you can use Single or Completable in your code without manually handle every CancellationException.

Unlike android-disposebag, this library doesn't use Android Architecture to listen the lifecycle because the class Lifecycle from Android Architecture doesn't emit states PRE_ATTACH, ATTACH, ACTIVITY_CREATED, VIEW_CREATED, DESTROY_VIEW, SAVE_INSTANCE_STATE, DESTROY_VIEW and DETACH while RxUIKotlin does.

Restrictions

It works only with RxJava3, it's designed to work with Kotlin (usage of extensions) and it dispose only the fragments from the AndroidX library.

The last supported RxJava2 version is the 1.2.3

Installation

implementation "com.vincentmasselis.rxuikotlin:rxuikotlin-core:3.0.0" //Use version 1.2.3 for RxJava2

Usage

Inside a Fragment:

anObservable
  .subscribe {
    //Do your stuff
  }
  .disposeOnState(FragmentState.DESTROY_VIEW, this)

It's exactly the same for activities:

  .disposeOnState(ActivityState.DESTROY, this)

and the view holders after you have overriden LifecycleAdapter and LifecycleViewHolder:

  .disposeOnState(ViewHolderState.ADAPTER_DETACH, this)

That's all !

RecyclerView and ViewHolder

Unlike Fragment and Activity, a RecyclerView.ViewHolder doesn't have explicit methods which represents a lifecyle, but, under the hood, there is a way to create a lifecycle-like behavior by using the modified version of RecyclerView.Adapter named LifecycleAdapter and the modified RecyclerView.ViewHolder named LifecycleViewHolder.

LifecycleAdapter creates 2 lifecycles "Window Attach-Detach" and "Adapter Attach-Detach". First calls LifecycleViewHolder.onWindowAttach and LifecycleViewHolder.onWindowDetach methods when the ViewHolder is dettached from the window and attached again a few moments before onBindViewHolder is called. Second calls LifecycleViewHolder.onAdapterAttach and LifecycleViewHolder.onAdapterDetach when the LifecycleAdapter is added or removed from the RecyclerView.

To use theses methods, you have to subclass LifecycleAdapter instead of RecyclerView.Adapter and LifecycleViewHolder instead of RecyclerView.ViewHolder, then, inside your ViewHolder, you can now override theses 4 methods onWindowAttach, onWindowDetach, onAdapterAttach and onAdapterDetach to create you own lifecycle behavior just like you do with a Fragment or an Activity.

override fun onAdapterAttach() {
  super.onAdapterAttach()
  anObservable
    .subscribe {
      //Do your stuff
    }
    .disposeOnState(ViewHolderState.ADAPTER_DETACH, this)
}

The only restraint of using LifecycleAdapter is the obligation to call subscribe:

myRecyclerView.subscribe(MyAdapter()).disposeOnState(ActivityState.DESTROY, this)

Repport an issue

https://github.com/VincentMasselis/RxUIKotlin/issues

TODO

• Example app