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
500
Kotlin-Flavored BuildScripts
importre
1
280
A tour of Standard Library
importre
0
92
Compose everything with rx & kotlin
importre
0
1.2k
Ready for Production
importre
2
310
Other Decks in Programming
See All in Programming
TSConfigからTypeScriptの世界を覗く
planck16
2
1.3k
イベントソーシングとAIの親和性ー物語とLLMに理解できるデータ
tomohisa
1
160
DevDay2025-OracleDatabase-kernel-addressing-history
oracle4engineer
PRO
6
1.6k
ソフトウェア品質特性、意識してますか?AIの真の力を引き出す活用事例 / ai-and-software-quality
minodriven
19
6.6k
がんばりすぎないコーディングルール運用術
tsukakei
1
180
Language Server と喋ろう – TSKaigi 2025
pizzacat83
2
640
AI Coding Agent Enablement in TypeScript
yukukotani
17
7k
UPDATEがシステムを複雑にする? イミュータブルデータモデルのすすめ
shimomura
0
120
抽象データ型について学んだ
ryounasso
0
200
漸進。
ssssota
0
900
コードに語らせよう――自己ドキュメント化が内包する楽しさについて / Let the Code Speak
nrslib
5
860
#QiitaBash TDDでAIに設計イメージを伝える
ryosukedtomita
2
1.6k
Featured
See All Featured
Scaling GitHub
holman
459
140k
Building Adaptive Systems
keathley
41
2.6k
Faster Mobile Websites
deanohume
307
31k
How GitHub (no longer) Works
holman
314
140k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.3k
How to train your dragon (web standard)
notwaldorf
92
6k
The MySQL Ecosystem @ GitHub 2015
samlambert
251
12k
Practical Orchestrator
shlominoach
188
11k
Large-scale JavaScript Application Architecture
addyosmani
512
110k
Why You Should Never Use an ORM
jnunemaker
PRO
56
9.4k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
180
53k
Six Lessons from altMBA
skipperchong
28
3.8k
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