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
Kotlin Flow
Search
José Caique Oliveira
June 21, 2019
Programming
0
110
Kotlin Flow
An early look at Kotlin Flow
José Caique Oliveira
June 21, 2019
Tweet
Share
More Decks by José Caique Oliveira
See All by José Caique Oliveira
Coroutines And Flow
jcaiqueoliveira
2
110
Testing your app
jcaiqueoliveira
0
290
Modularizando seu app
jcaiqueoliveira
0
71
Nova Api de Localização Android
jcaiqueoliveira
0
78
Arquitetura para android
jcaiqueoliveira
6
320
Kotlin por onde começar?
jcaiqueoliveira
1
89
Introdução ao Android
jcaiqueoliveira
1
80
Arquitetura para projetos Android
jcaiqueoliveira
1
220
Kotlin 1.1
jcaiqueoliveira
0
120
Other Decks in Programming
See All in Programming
PipeCDのプラグイン化で目指すところ
warashi
1
280
Result型で“失敗”を型にするPHPコードの書き方
kajitack
5
920
Modern Angular with Signals and Signal Store:New Rules for Your Architecture @enterJS Advanced Angular Day 2025
manfredsteyer
PRO
0
220
Google Agent Development Kit でLINE Botを作ってみた
ymd65536
2
250
Agentic Coding: The Future of Software Development with Agents
mitsuhiko
0
110
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
930
チームで開発し事業を加速するための"良い"設計の考え方 @ サポーターズCoLab 2025-07-08
agatan
1
430
猫と暮らす Google Nest Cam生活🐈 / WebRTC with Google Nest Cam
yutailang0119
0
140
技術同人誌をMCP Serverにしてみた
74th
1
650
「Cursor/Devin全社導入の理想と現実」のその後
saitoryc
0
830
PicoRuby on Rails
makicamel
2
130
生成AI時代のコンポーネントライブラリの作り方
touyou
1
230
Featured
See All Featured
Site-Speed That Sticks
csswizardry
10
690
Documentation Writing (for coders)
carmenintech
72
4.9k
Typedesign – Prime Four
hannesfritz
42
2.7k
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
229
22k
How to Think Like a Performance Engineer
csswizardry
25
1.7k
Faster Mobile Websites
deanohume
307
31k
Easily Structure & Communicate Ideas using Wireframe
afnizarnur
194
16k
How STYLIGHT went responsive
nonsquared
100
5.6k
Building Adaptive Systems
keathley
43
2.7k
BBQ
matthewcrist
89
9.7k
The Illustrated Children's Guide to Kubernetes
chrisshort
48
50k
GraphQLとの向き合い方2022年版
quramy
49
14k
Transcript
KOTLIN FLOW JOSÉ CAIQUE
produce(capacity = 20) { (0..10).forEach { send(it) println("sent $it") }
} //emmit : 1,2,3 … val intFlow = flow { for (i in 0 until 10) { emit(i) println("sent flow $i") } } // intFlow.collect{ } // 1,2,3… HOT CHANNEL COLD STREAM implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.0-M1'
@ExperimentalCoroutinesApi public interface Flow<out T> { @InternalCoroutinesApi public suspend fun
collect(collector: FlowCollector<T>) } BackPressure by Default
BUILDERS ▸ (0..2).asFlow() ▸ flow{ emit(1) } ▸ flowOf(1, 2,
3, 4, 5) ▸ channelFlow { send(1) } ▸ emptyFlow<T>()
(0..1).asFlow() .map { println("Thread0 ${Thread.currentThread().name}") it*it } .filter { println("Thread1
${Thread.currentThread().name}") it % 4 == 0 } .flowOn(Dispatchers.IO) .map { println("Thread2 ${Thread.currentThread().name}") it * 2 } .flowOn(Dispatchers.Default) Thread0 DefaultDispatcher-worker-2 Thread1 DefaultDispatcher-worker-2 Thread0 DefaultDispatcher-worker-2 Thread1 DefaultDispatcher-worker-2 Thread2 main
//requestA(Flow) -> 1000L //requestB(Flow) -> 2000L requestA() .zip(requestB()) { requestA,
requestB -> requestA + requestB }.collect { println(it) } Total: ~2100L
//requestA(suspend) -> 1000L //requestB(suspend) -> 2000L channelFlow<Pair<Int, String>> { val
result1 = async { requestA() } val result2 = async { requestB() } val result3 = result1.await() to result2.await() send(result3) }.collect { println(it) } // buffer, still cold stream Total: ~2100L
val myFlow = flow { // GlobalScope.launch { // is
prohibited // launch(Dispatchers.IO) { // is prohibited // withContext(CoroutineName("myFlow")) // is prohibited emit(1) // OK coroutineScope { emit(2) // OK -- still the same coroutine } }
channelFlow { launch(IO){ send(requestA()) } launch(Main) { send(requestB()) } }.collect
{ println(it) }
val broadcast: ConflatedBroadcastChannel<User> // emitting launch { broadcast.send(user) } //
listening broadcast.consumeEach { service .retrieve(it) .map { it.getOrNull() } .collect { it?.let { … } } } //close broadcast.close()
EXTENSIONS ‣ broadcastIn ‣ buffer ‣ collect ‣ combineLatest ‣
conflate ‣ count ‣ debounce ‣ delayEach ‣ delayFlow ‣ distinctUntilChanged ‣ distinctUntilChangedBy ‣ drop ‣ dropWhile ‣ filter ‣ filterIsInstance ‣ filterNot ‣ filterNotNull ‣ first ‣ flatMapConcat ‣ flatMapMerge ‣ flattenConcat ‣ flattenMerge ‣ flowWith ‣ fold ‣ map ‣ mapNotNull ‣ onEach ‣ onErrorCollect ‣ onErrorReturn ‣ produceIn ‣ reduce ‣ retry ‣ sample ‣ scan ‣ scanFold ‣ scanReduce ‣ single ‣ singleOrNull ‣ switchMap ‣ take ‣ takeWhile ‣ toCollection ‣ toList ‣ toSet ‣ transform ‣ zip
fun <T> Flow<T>.startWith(start: T) = flow { collect { value
-> emit(start) emit(value) } } flowOf("Caique") .startWith("Jose") .collect { println(it) } // José // Caique EASY TO CREATE EXTENSIONS
MORE EXTENSIONS ARE COMING https://github.com/Kotlin/kotlinx.coroutines/issues/1263 https://github.com/Kotlin/kotlinx.coroutines/issues/1261 https://github.com/Kotlin/kotlinx.coroutines/issues/1247 https://github.com/Kotlin/kotlinx.coroutines/issues/1186
JOSÉ CAIQUE ▸ Software Engineer ▸ Computer Science by UFS
▸ Android Tech Lead at Stone ▸ Speaker
J C A I Q U E _ J O
S E C A I Q U E J O S E C A I Q U E T H A N K S