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
#QiitaBash MCPのセキュリティ
ryosukedtomita
0
380
Bytecode Manipulation 으로 생산성 높이기
bigstark
2
390
Go1.25からのGOMAXPROCS
kuro_kurorrr
1
820
エンジニア向け採用ピッチ資料
inusan
0
170
PHP 8.4の新機能「プロパティフック」から学ぶオブジェクト指向設計とリスコフの置換原則
kentaroutakeda
2
670
エラーって何種類あるの?
kajitack
5
320
Benchmark
sysong
0
280
PipeCDのプラグイン化で目指すところ
warashi
1
210
WindowInsetsだってテストしたい
ryunen344
1
200
XP, Testing and ninja testing
m_seki
3
220
コードの90%をAIが書く世界で何が待っているのか / What awaits us in a world where 90% of the code is written by AI
rkaga
48
32k
都市をデータで見るってこういうこと PLATEAU属性情報入門
nokonoko1203
1
580
Featured
See All Featured
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
124
52k
Adopting Sorbet at Scale
ufuk
77
9.4k
The Straight Up "How To Draw Better" Workshop
denniskardys
234
140k
Bootstrapping a Software Product
garrettdimon
PRO
307
110k
Imperfection Machines: The Place of Print at Facebook
scottboms
267
13k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
48
5.4k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
32
2.3k
Building Better People: How to give real-time feedback that sticks.
wjessup
367
19k
Connecting the Dots Between Site Speed, User Experience & Your Business [WebExpo 2025]
tammyeverts
5
230
Building Adaptive Systems
keathley
43
2.6k
The Success of Rails: Ensuring Growth for the Next 100 Years
eileencodes
45
7.5k
Measuring & Analyzing Core Web Vitals
bluesmoon
7
490
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