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
Cycle for Android
Search
Jaewe Heo
August 03, 2016
Programming
3
1.9k
Cycle for Android
functional and reactive programming in Kotlin
Jaewe Heo
August 03, 2016
Tweet
Share
More Decks by Jaewe Heo
See All by Jaewe Heo
Kotlin, Gradle and AWS SAM
importre
1
530
Kotlin-Flavored BuildScripts
importre
1
310
A tour of Standard Library
importre
0
100
Compose everything with rx & kotlin
importre
0
1.2k
Ready for Production
importre
2
310
Other Decks in Programming
See All in Programming
Domain-centric? Why Hexagonal, Onion, and Clean Architecture Are Answers to the Wrong Question
olivergierke
3
980
NIKKEI Tech Talk#38
cipepser
0
250
PHPに関数型の魂を宿す〜PHP 8.5 で実現する堅牢なコードとは〜 #phpcon_hiroshima / phpcon-hiroshima-2025
shogogg
1
340
なんでRustの環境構築してないのにRust製のツールが動くの? / Why Do Rust-Based Tools Run Without a Rust Environment?
ssssota
14
46k
あなたとKaigi on Rails / Kaigi on Rails + You
shimoju
0
190
登壇は dynamic! な営みである / speech is dynamic
da1chi
0
360
AI Agent 時代的開發者生存指南
eddie
4
2.1k
monorepo の Go テストをはやくした〜い!~最小の依存解決への道のり~ / faster-testing-of-monorepos
convto
2
560
Goで実践するドメイン駆動開発 AIと歩み始めた新規プロダクト開発の現在地
imkaoru
4
910
Introduce Hono CLI
yusukebe
6
3.1k
Building, Deploying, and Monitoring Ruby Web Applications with Falcon (Kaigi on Rails 2025)
ioquatix
4
2.5k
kiroとCodexで最高のSpec駆動開発を!!数時間で web3ネイティブなミニゲームを作ってみたよ!
mashharuki
0
930
Featured
See All Featured
The Invisible Side of Design
smashingmag
302
51k
How To Stay Up To Date on Web Technology
chriscoyier
791
250k
Understanding Cognitive Biases in Performance Measurement
bluesmoon
31
2.7k
Leading Effective Engineering Teams in the AI Era
addyosmani
7
640
[RailsConf 2023 Opening Keynote] The Magic of Rails
eileencodes
31
9.7k
Building Adaptive Systems
keathley
44
2.8k
Improving Core Web Vitals using Speculation Rules API
sergeychernyshev
21
1.2k
Keith and Marios Guide to Fast Websites
keithpitt
411
23k
StorybookのUI Testing Handbookを読んだ
zakiyama
31
6.2k
Fashionably flexible responsive web design (full day workshop)
malarkey
407
66k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
658
61k
Exploring the Power of Turbo Streams & Action Cable | RailsConf2023
kevinliebholz
36
6.1k
Transcript
Cycle for Android Jaewe Heo · !iiid! · @importre Aug.
3, 2016 functional and reactive programming in Kotlin
import importre
About me • Android • Rx • Kotlin - Kotlin
Korea • Electron - Electron Korea • React - react-photonkit • Alfred workflows
alfred-mdi
alfred-pg
alfred-gi
alfred-hl
alfred-awe
alfred-tidy
Cycle for Android functional and reactive programming in Kotlin
Cycle.js http://cycle.js.org/
HCI (Human-Computer Interaction) two-way process
None
None
None
Mutual observation Reactive Programming
Two-way process val y = human(x)
Two-way process val y = human(x) val x = computer(y)
Two-way process val y = human(x) val x = computer(y)
?!
val x = computer(human(x))
Streams
Programming Foo Bar
Programming Foo Bar
Programming Foo Bar
Imperative Programming Foo Bar Proactive Passive Fooо Bar ࢚కܳ ߸҃ೡ
ࣻ . Barח ־о ೱਸ ח ݽܲ.
// This is inside the `Foo` module fun onNetworkRequest() {
// ... bar.incrementCounter() // ... } Example of the Imperative Programming
Barח ৻ࠗ ߮ী ߈ೞৈ न ࢚కܳ ҙܻೠ. Reactive Programming Foo
Bar Listenable Reactive Fooח ־ҳীѱ ೱਸ ח ݽܲ.
// This is inside the `Bar` module foo.addOnNetworkRequestListener { //
`this` is Bar this.incrementCounter() } Example of the Reactive Programming
Solve the cyclic dependency val y = human(x) val x
= computer(y)
Solve the cyclic dependency val proxyX = ReplaySubject.create<Any>() val y
= human(proxyX) val x = computer(y)
Solve the cyclic dependency val proxyX = ReplaySubject.create<Any>() val y
= human(proxyX) val x = computer(y) x.imitate(proxyX)
None
kotlin-cycle Cycle for Android (written in Kotlin)
Hello Example • ܴਸ ੍ (read) • ݫद ߸҃ (model)
• ݫदܳ ചݶী ࠁৈષ (write)
None
HelloActivity.kt class HelloActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?)
{ super.onCreate(savedInstanceState) setContentView(R.layout.activity_hello) Cycle.run(main, DomSource()) } private val main = { sources: Sources -> val change = sources.dom().select(helloEdit).textChanges() val model = change.map(::greeting) val view = model.map { message -> onUpdateView(message) } Sinks(DomSink(view)) } private fun onUpdateView(message: CharSequence) = { helloText.text = message } }
HelloActivity.kt class HelloActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?)
{ super.onCreate(savedInstanceState) setContentView(R.layout.activity_hello) Cycle.run(main, DomSource()) } private val main = { sources: Sources -> val change = sources.dom().select(helloEdit).textChanges() val model = change.map(::greeting) val view = model.map { message -> onUpdateView(message) } Sinks(DomSink(view)) } private fun onUpdateView(message: CharSequence) = { helloText.text = message } }
HelloActivity.kt class HelloActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?)
{ super.onCreate(savedInstanceState) setContentView(R.layout.activity_hello) Cycle.run(main, DomSource()) } private val main = { sources: Sources -> val change = sources.dom().select(helloEdit).textChanges() val model = change.map(::greeting) val view = model.map { message -> onUpdateView(message) } Sinks(DomSink(view)) } private fun onUpdateView(message: CharSequence) = { helloText.text = message } }
Kotlin-flavored Examples
HelloCycleActivity.kt class HelloCycleActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?)
{ super.onCreate(savedInstanceState) setContentView(R.layout.activity_hello) cycle { val change = dom.select(helloEdit).textChanges() val model = change.map(::greeting) model.map { message -> { helloText.text = message } } } } }
HelloCycleActivity.kt class HelloCycleActivity : BaseActivity() { override fun onCreate(savedInstanceState: Bundle?)
{ super.onCreate(savedInstanceState) setContentView(R.layout.activity_hello) cycle { val change = dom.select(helloEdit).textChanges() val model = change.map(::greeting) model.map { message -> { helloText.text = message } } } } }
Hello.kt fun greeting(name: CharSequence) = "Hello, $name!"
HelloTest.kt class HelloTest { @Test fun testGreeting() { val actual
= greeting("cycle") val expected = "Hello, cycle!" assertEquals(expected, actual) } }
BMI Example • ރޖѱ, ఃী ೠ ୡӝ ч ࢸ (properties)
• SeekBarܳ (read) • BMI ҅ • Ѿҗܳ ചݶী ࠁৈષ (write)
BmiActivity.kt cycle { val weightProps = Observable.just(Props(min = 40, max
= 140, value = 70)) val heightProps = Observable.just(Props(min = 140, max = 210, value = 170)) // Intent val (weightStream, heightStream) = intent(dom, heightProps, weightProps) // Model val stateStream = model(weightStream, heightStream, weightProps, heightProps) // View stateStream.map { state -> onUpdateView(state) } }
None
BmiActivity.kt private val intent = { dom: DomSource, heightProps: Observable<Props>,
weightProps: Observable<Props> -> val weightChangeStream = dom .select(weightSeekBar.apply { val props = weightProps.toBlocking().first() max = props.max - props.min progress = props.value - props.min }) .userChanges() val heightChangeStream = dom .select(heightSeekBar.apply { val props = heightProps.toBlocking().first() max = props.max - props.min progress = props.value - props.min }) .userChanges() Pair(weightChangeStream, heightChangeStream) }
BmiActivity.kt private val model = { weightChangeStream: Observable<Int>, heightChangeStream: Observable<Int>,
weightProps: Observable<Props>, heightProps: Observable<Props> -> Observable.combineLatest( weightChangeStream, heightChangeStream, weightProps, heightProps, ::calculateBmi) }
BmiActivity.kt private fun onUpdateView(state: State) = { unwrap(weightText, heightText, bmiText)
{ w, h, b -> w.text = "Weight: ${state.weight} kg" h.text = "Height: ${state.height} cm" b.text = "Bmi: ${state.bmi}" } nah { toast(R.string.error_undefined_views) } } kotlin-unwrap
Bmi.kt data class State(val weight: Int, val height: Int, val
bmi: Int) data class Props(val min: Int, val max: Int, val value: Int) fun calculateBmi(weight: Int, height: Int, weightProps: Props, heightProps: Props): State { val realHeight = height + heightProps.min val realWeight = weight + weightProps.min val heightMeters = realHeight * 0.01F val bmi = Math.round(realWeight / (heightMeters * heightMeters)) return State(realWeight, realHeight, bmi) }
REST Example • ࢜۽Ҋஜ (read) • ୡӝীח ࢜۽Ҋஜ হ ࢲߡ۽
ࠗఠ ؘఠܳ ੍যঠ ೣ • request(write) data -> response(read) data • Ѿҗܳ ചݶী ࠁৈષ (write) • ߡౡਸ ־ܴ (read) • షझܳ ڸ (write) https://jsonplaceholder.typicode.com/
UsersActivity.kt cycle { error = onError // Intent val usersStream
= api.getUsers() val refreshStream = dom .select(refreshView) .refreshes() .startWith(null as Void?) // Model val modelStream = Observable .combineLatest(usersStream, refreshStream) { users, refresh -> users } // View modelStream.map { users -> onUpdateView(users) } }
Extensions fun ImageView.loadUrl(imageUrl: String) = Picasso.with(context).load(imageUrl).into(this) fun Activity.toast(@StringRes id: Int)
= Toast.makeText(this, id, Toast.LENGTH_SHORT).show() fun Activity.toast(message: String) = Toast.makeText(this, message, Toast.LENGTH_SHORT).show() fun RecyclerView.ViewHolder.toast(message: String) = Toast.makeText(itemView.context, message, Toast.LENGTH_SHORT).show()
UserViewHolder.kt itemView.locationImage.loadUrl(url) itemView.nameText.text = user.name cycle { val emailChange =
dom.select(itemView.emailButton).clicks().map { ButtonType.EMAIL } val callChange = dom.select(itemView.callButton).clicks().map { ButtonType.CALL } val change = Observable.merge(emailChange, callChange) change.map { type -> show(user, type) } }
UserViewHolder.kt private fun show(user: User, type: ButtonType) = { toast(when
(type) { ButtonType.EMAIL -> user.email ButtonType.CALL -> user.phone }) }
Conclusion
Conclusion • ӭՔೞפ જӟೠؘ…
Conclusion • functional ೠо? • reactive ೠо? • productionী ਊ
оמೠо?
Conclusion • functional ೠо? • reactive ೠо? • productionী ਊ
оמೠо?
References
References - importre • https://github.com/importre/kotlin-cycle • https://github.com/importre/kotlin-unwrap • https://github.com/importre/ready-for-production •
Data class and Equality • Function Literals with Receiver • let, with, run, apply, use(using)
References - cycle.js • http://cycle.js.org/ • https://github.com/cyclejs-community/cycle-android
References - video • Unidirectional data flow architectures • What
if the user was a function?
val coWorker = true cycle { val change = dom
.select(toggle.apply { isChecked = true }) .checkedChanges() val model = change .map { onOff -> "উ٘۽٘ ѐߊܳ ݽभפ: $onOff" } .map { recruit -> "Riiid!\n$recruit" } model.map { message -> { checkText.text = message } } }
[email protected]
Thank you