Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Subscribe RxJava vs LiveData English
Search
Bruno Aybar
October 20, 2018
Programming
0
140
Subscribe RxJava vs LiveData English
2018 edition, in English
Bruno Aybar
October 20, 2018
Tweet
Share
More Decks by Bruno Aybar
See All by Bruno Aybar
Compose: Estados y Recomposición
bruno125
0
31
Annotation Processors vs Kotlin Plugins
bruno125
0
53
Understanding Kotlin Type System
bruno125
1
56
Subscribe { RxJava vs LiveData }
bruno125
1
290
Yo también quiero usar Kotlin
bruno125
0
310
Kotlin en Fandango Latam
bruno125
0
160
Android Custom Views
bruno125
0
210
Developing a Fan Made Version Of My University's App
bruno125
0
110
Other Decks in Programming
See All in Programming
SQLアンチパターン第2版 データベースプログラミングで陥りがちな失敗とその対策 / Intro to SQL Antipatterns 2nd
twada
PRO
26
8k
The Niche of CDK Grant オブジェクトって何者?/the-niche-of-cdk-what-isgrant-object
hassaku63
1
690
코딩 에이전트 체크리스트: Claude Code ver.
nacyot
0
980
DMMを支える決済基盤の技術的負債にどう立ち向かうか / Addressing Technical Debt in Payment Infrastructure
yoshiyoshifujii
4
590
テスト駆動Kaggle
isax1015
1
880
slogパッケージの深掘り
integral0515
0
120
AIともっと楽するE2Eテスト
myohei
9
3.1k
What's new in AppKit on macOS 26
1024jp
0
170
チームのテスト力を総合的に鍛えて品質、スピード、レジリエンスを共立させる/Testing approach that improves quality, speed, and resilience
goyoki
5
1.2k
コーディングエージェント概観(2025/07)
itsuki_t88
0
130
可変性を制する設計: 構造と振る舞いから考える概念モデリングとその実装
a_suenami
2
210
おやつのお供はお決まりですか?@WWDC25 Recap -Japan-\(region).swift
shingangan
0
150
Featured
See All Featured
Building Applications with DynamoDB
mza
95
6.5k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.4k
Become a Pro
speakerdeck
PRO
29
5.4k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
181
54k
How to train your dragon (web standard)
notwaldorf
96
6.1k
Designing for Performance
lara
610
69k
Put a Button on it: Removing Barriers to Going Fast.
kastner
60
3.9k
The Cost Of JavaScript in 2023
addyosmani
51
8.6k
Learning to Love Humans: Emotional Interface Design
aarron
273
40k
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
126
53k
Git: the NoSQL Database
bkeepers
PRO
431
65k
Site-Speed That Sticks
csswizardry
10
720
Transcript
Subscribe { RxJava vs LiveData }
@brunoaybarg @bruno.aybar Bruno125 Bruno Aybar Android Dev Peru Organizer Android
Engineer
• Allow us to observe changes over some kind of
data, and to react to those changes. • Propose a reactive paradigm • Do they do the same? RxJava & LiveData
OBSERVER pattern
OBSERVER pattern Design pattern that defines a dependency between objects
(…), in which one of them changes its state, it notifies about it to all of its dependants
OBSERVER RxJava LiveData pattern
RxJava
RxJava An API for asynchronous programming with observable streams Is
a combination of the best ideas from the Observer pattern, the Iterator pattern, and functional programming ReactiveX RxJava RxSwift RxJS Rx.NET RxPY RxPHP …
Stream of Data states events data data data
Fuente: Imagen tomada de https://www.pinterest.com/pin/749708669188692420/
Subscriber<T>
Observable<T>
Flowable<T> RxJava 2:
package org.reactivestreams; public interface Subscriber<T> { public void onNext(T
t); public void onError(Throwable t); public void onComplete(); }
Flowable.just(1)
Flowable.just(1) Flowable.fromArray(1,2,3)
Flowable.create<Int>({ s -> }, BackpressureStrategy.BUFFER) Flowable.fromArray(1,2,3) Flowable.just(1)
Flowable.create<Int>({ s -> s.onNext(1) }, BackpressureStrategy.BUFFER) Flowable.fromArray(1,2,3)
Flowable.just(1)
Flowable.create<Int>({ s -> s.onNext(1) s.onNext(2) }, BackpressureStrategy.BUFFER) Flowable.just(1)
Flowable.fromArray(1,2,3)
Flowable.create<Int>({ s -> s.onNext(1) s.onNext(2) s.onNext(3) }, BackpressureStrategy.BUFFER) Flowable.just(1)
Flowable.fromArray(1,2,3)
Flowable.create<Int>({ s -> s.onNext(1) s.onNext(2) s.onNext(3) s.onComplete() }, BackpressureStrategy.BUFFER)
Flowable.just(1) The stream ends here! Flowable.fromArray(1,2,3)
Flowable.create<Int>({ s -> s.onNext(1) s.onNext(2) s.onNext(3) s.onComplete() s.onNext(4) }, BackpressureStrategy.BUFFER)
Flowable.just(1) Not emitted Flowable.fromArray(1,2,3)
Flowable.create<Int>({ s -> s.onNext(1) s.onNext(2) s.onNext(3) s.onError(Throwable(“Error!")) s.onNext(4) }, BackpressureStrategy.BUFFER)
Flowable.just(1) Not emitted Flowable.fromArray(1,2,3)
Flowable.fromArray(1,2,3) Flowable.create<Int>({ s -> // heavy transaction... // async operation...
}, BackpressureStrategy.BUFFER) Flowable.just(1)
Event subscription
Flowable.just(1).subscribe( { value -> log("onNext: $value") }, { error ->
log("onError: $error")}, { log("onComplete!") } )
Flowable.just(1).subscribe( { value -> log("onNext: $value") }, { error ->
log("onError: $error")}, { log("onComplete!") } )
val subscription = Flowable.just(1).subscribe( { value -> log("onNext: $value") },
{ error -> log("onError: $error")}, { log("onComplete!") } ) subscription.dispose()
Handling Threads
Controller UI DataSource
Controller Presenter ViewModel DataSource UI
Controller DataSource UI
Controller DataSource UI Background
Controller DataSource UI UI Thread
Flowable.just(1).subscribe( { value -> log("onNext: $value") }, { error ->
log("onError: $error")}, { log("onComplete!") } )
Flowable.just(1) .subscribeOn(Schedulers.computation()) .subscribe( { value -> log("onNext: $value") }, {
error -> log("onError: $error")}, { log("onComplete!") } ) Thread in which the operation will be performed
Flowable.just(1) .subscribeOn(Schedulers.computation()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( { value -> log("onNext: $value") },
{ error -> log("onError: $error")}, { log("onComplete!") } ) Thread in which we will listen to the stream emissions
Operations
Flowable.fromArray(1,2,3,4) .filter { it % 2 == 0 }
Flowable.fromArray(1,2,3,4) .filter { it % 2 == 0 } .map
{ it + 10 } Flowable.just(User(“1”, “Bruno”)) .map { it.name }
Combine CombineLatest And/Then/When Zip Switch Join ... Filtering Filter Distinct
First Last Take ... Transform Map FlatMap Scan GroupBy Buffer ... More: http:/ /reactivex.io/documentation/ operators.html
Steep learning curve
LiveData
LiveData Room Lifecycle ViewModel ARCHITECTURE COMPONENTS
LiveData Lifecycle +
Flowable.fromArray(1,2,3)
Flowable.fromArray(1,2,3) 1 2 3 LiveData<Int>
Flowable.fromArray(1,2,3) 1 2 3 MutableLiveData<Integer> data = new MutableLiveData<>();
data.setValue(1); //UI thread data.setValue(2); //UI thread data.postValue(3); //Background thread
Flowable.fromArray(1,2,3) 1 2 3 MutableLiveData<Integer> data = new MutableLiveData<>();
data.setValue(1); //UI thread data.setValue(2); //UI thread data.postValue(3); //Background thread
Event subscription
data.observe(lifecycleOwner, new Observer<Integer>() { @Override public void onChanged(@Nullable Integer value)
{ log("onChanged: $value”) } });
data.observe(lifecycleOwner, Observer<Int> { value -> log("onChanged: $value”) })
data.observe(lifecycleOwner, Observer<Int> { value -> log("onChanged: $value”) })
data.observe(lifecycleOwner, Observer<Int> { value -> log("onChanged: $value”) })
None
LifecycleOwner class that contains information about a component lifecycle, and
allow other objects to observe its changes
LifecycleOwner class that contains information about a component lifecycle, and
allow other objects to observe its changes Destroyed Created Started Resumed Initialized
None
LifecycleObserver allows you to observe the current state of a
LifecycleOwner
LifecycleObserver public class MyObserver implements LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) public
void connectListener() { } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) public void disconnectListener() { } }
Flowable <Int> Activity 1 2 3 subscribes to data.subscribe {
value -> textView.setText("Text " + value) }
Flowable <Int> Activity subscribes to data.subscribe { value -> textView.setText("Text
" + value) } destroyed 4 5 6
LiveData <Int> Activity subscribes to data.observe(lifecycleOwner, { value -> textView.setText("Text
" + value) }) destroyed X
LiveData <Int> Activity subscribes to data.observe(lifecycleOwner, { value -> textView.setText("Text
" + value) }) STARTED | RESUMED
LiveData <Int> Activity subscribes to data.observe(lifecycleOwner, { value -> textView.setText("Text
" + value) }) STARTED | RESUMED 6
Handling threads
MutableLiveData<Integer> data = new MutableLiveData<>(); data.setValue(1); //UI thread data.postValue(2);
//Background thread
MutableLiveData<Integer> data = new MutableLiveData<>(); data.setValue(1); //UI thread data.postValue(2);
//Background thread data.observe(lifecycleOwner, { value -> // executes in UI thread })
Operations
val userLiveData: LiveData<User> = … val userNameLiveData = Transformations.map(
userLiveData, { it.name }) Map SwitchMap Custom Transformations
+ LiveData Lifecycle + ViewModel + Room
RxJava vs LiveData Explicit code ✔ Thread handling ✔ Powerful
Operators ✔ Steep learning curve ✘ Really simple ✔ Android-oriented ✔ Integration with AC ✔ Not so powerful operators ✘ Library compatibility (i.e. Retrofit) ✔ Over-engineered? ✘ Portable knowledge ✔
¯\_(ツ)_/¯ RxJava vs LiveData
Controller Presenter ViewModel Data Sources UI
Controller Presenter ViewModel Data Sources UI LiveData
Controller Presenter ViewModel Data Sources UI RxJava
¯\_(ツ)_/¯ RxJava vs LiveData
Additional Material Intro to RxJava (Christina Lee) https:/ /www.youtube.com/watch?v=XLH2v9deew0 Learning
Rx (for Android) by Example https:/ /www.youtube.com/watch?v=k3D0cWyNno4 Common RxJava Mistakes https:/ /www.youtube.com/watch?v=QdmkXL7XikQ RxJava in Baby Steps https:/ /www.youtube.com/watch?v=YPf6AYDaYf8 RxMarbles http:/ /rxmarbles.com/
Live Data docs https:/ /developer.android.com/topic/libraries/architecture/livedata.html LiveData & Lifecycle https:/ /www.youtube.com/watch?v=jCw5ib0r9wg
ViewModels, LiveData and Lifecycles, oh my! https:/ /www.youtube.com/watch?v=SlZVYkhoSq8 Android lifecycle-aware components codelab https:/ /codelabs.developers.google.com/codelabs/android-lifecycles Additional Material
@brunoaybarg @bruno.aybar Bruno125 Bruno Aybar Android Dev Perú Organizer Android
Engineer @ Avantica Gracias! https://speakerdeck.com/bruno125/subscribe-rxjava-vs-livedata-2018