Kotlin コルーチンを理解しよう

©2018 Lang-8 Inc. ALL Rights Reserved. wീ໦ढ़޿ w!TZTZBHJ w$50PG w"OESPJE&OHJOFFS
"CPVU.F Jetpack Handbook ʲC94৽ץʳ ʮୈ6ষ WorkManagerͱόοΫάϥ΢ϯυλεΫʯ ॻ͖·ͨ͠

©2018 Lang-8 Inc. ALL Rights Reserved. ©2018 Lang-8 Inc. ALL
Rights Reserved. https://hinative.com 8FBSFIJSJOH

©2018 Lang-8 Inc. ALL Rights Reserved. wίϧʔνϯͱ͸ͳʹ͔ w,PUMJO͸ͲͷΑ͏ʹίϧʔνϯΛ࣮ݱ ͍ͯ͠Δͷ͔ w,PUMJOίϧʔνϯͷجຊతͳ࢖͍ํ
ࠓ೔࿩͢͜ͱ

©2018 Lang-8 Inc. ALL Rights Reserved. w $PCPMίϯύΠϥΛܰྔʹ࣮ ૷͢ΔͨΊʹίϧʔνϯͷ֓೦ Λಋೖͨ͠
w ͋Δ৚݅ԼͰϓϩάϥϜΛ෼཭ ͢Δͱಠཱͯͦ͠ΕͧΕಈ࡞Ͱ ͖Δͱ͍͏ΞΠσΞ w DPSPVUJOFɺͭ·Γର౳ͷϧʔ νϯͱ͍͏ҙຯɻ͓ޓ͍Λݺͼ ग़੍ͯ͠ޚͰ͖Δؔ܎ ϝϧϰΟϯɾίϯ΢ΣΠ ͷ೥ͷ࿦จ͕ॳग़ IUUQNFMDPOXBZDPN)PNFQEGDPNQJMFSQEG

©2018 Lang-8 Inc. ALL Rights Reserved. w "DPSPVUJOFJTBOJOTUBODFPGTVTQFOEBCMF DPNQVUBUJPO*UJTDPODFQUVBMMZTJNJMBSUPB UISFBE
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©2018 Lang-8 Inc. ALL Rights Reserved. w ίϧʔνϯ͸ɺҰ࣌ఀࢭՄೳͳܭࢉͷΠϯελϯεͰ͢ɻͦ Ε͸֓೦తʹ͸εϨουʹࣅ͍ͯ·͢ɻͭ·Γɺ࣮ߦ͢Δίʔ υϒϩοΫΛ࣋ͪɺಉ༷ͷϥΠϑαΠΫϧΛ࣋ͪɺ࡞੒͞Ε
ىಈ͞Ε·͕͢ɺಛఆͷεϨουʹଋറ͞Ε͍ͯ·ͤΜɻ͋ ΔεϨουͰ࣮ߦΛதஅ͠ɺผͷεϨουͰ࠶։͢Δ͜ͱ͕ ͋Γ·͢ɻ͞Βʹɺ'VUVSF΍1SPNJTTͷΑ͏ʹɺԿΒ͔ ͷ݁Ռ΍ྫ֎͕͋Δ৔߹͕͋Γ·͢ɻ $PSPVUJOFTGPS,PUMJOʹΑΔͱʜ IUUQTHJUIVCDPN,PUMJOLPUMJODPSPVUJOFTCMPCNBTUFSLPUMJODPSPVUJOFTJOGPSNBMNEUFSNJOPMPHZ

©2018 Lang-8 Inc. ALL Rights Reserved. wαϒϧʔνϯͱҟͳΓɺঢ়ଶ؅ཧΛ ҙࣝͤͣʹߦ͑ΔͨΊɺڠௐతॲཧɺ ΠςϨʔλɺແݶϦετɺύΠϓͳ Ͳɺܧଓঢ়گΛ࣋ͭϓϩάϥϜ͕༰
қʹهड़Ͱ͖Δɻ 8JLJQFEJBʹΑΔͱʜ IUUQTKBXJLJQFEJBPSHXJLJ&#&"#&#$&&#

©2018 Lang-8 Inc. ALL Rights Reserved. wҰ࣌ఀࢭՄೳͳܭࢉͷΠϯελϯε wεϨουͷΑ͏ʹ࣮ߦ͢ΔίʔυϒϩοΫΛ࣋ͪɺಉ ༷ͷϥΠϑαΠΫϧΛ࣋ͪɺ࡞੒͞Εىಈ͞ΕΔ͕ɺ ಛఆͷεϨουʹଋറ͞Εͳ͍
w'VUVSF΍1SPNJTTͷΑ͏ʹɺԿΒ͔ͷ݁Ռ΍ྫ֎ ͕͋Δ৔߹͕͋Δ wܧଓঢ়گΛ࣋ͭϓϩάϥϜ͕༰қʹهड़Ͱ͖Δ ίϧʔνϯͱ͸ʜ

©2018 Lang-8 Inc. ALL Rights Reserved. Ұ࣌ఀࢭՄೳͳܭࢉͷΠϯελϯε fun loadProfile(id: Int)
{ val profile = getProfile(id) showProfile(profile) } αϒϧʔνϯ ίϧʔνϯ ։͔࢝ΒϦλʔϯ·Ͱ͕Ұ ͭͷॲཧ୯Ґ தஅ ࠶։ ॲཧͷ్தͰҰ࣌ఀࢭ ͕Մೳ launch { val profile = getProfile(id).await() showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. εϨουͱίϧʔνϯ Thread { val
profile = getProfile(token) showProfile(profile) }.start() εϨου ίϧʔνϯ ίʔυϒϩοΫͱϥΠϑα ΠΫϧΛ࣋ͪɺ࡞੒ͱىಈ ͕͞ΕΔ εϨουʹࣅ͍ͯΔ͕ ಛఆͷεϨουʹଋറ ͞Εͳ͍ launch { val profile = getProfile(token).await() showProfile(profile) } ͲͷεϨουͰ࣮ߦ͞ΕΔ͔͸ίϧʔνϯࣗ਎͸ؾʹ͠ͳ͍

©2018 Lang-8 Inc. ALL Rights Reserved. 'VUVSF΍1SPNJTTͷΑ͏ʹ஋Λฦ͢৔߹͕͋Δ fun getProfile(id: Int)
= async { //… return profile } launch { val profile = getProfile(id).await() showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. 'VUVSF΍1SPNJTTͷΑ͏ʹ஋Λฦ͢৔߹͕͋Δ ஋Λฦ͢ίϧʔνϯ fun getProfile(id:
Int) = async { //… return profile } launch { val profile = getProfile(id).await() showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. 'VUVSF΍1SPNJTTͷΑ͏ʹ஋Λฦ͢৔߹͕͋Δ fun getProfile(id: Int)
= async { //… return profile } launch { val profile = getProfile(id).await() showProfile(profile) } ผͷίϧʔνϯΛىಈͯࣗ͠਎͸தஅ ͠ɺ݁ՌΛड͚औͬͯ࠶։͢Δ

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ࣋ͭϓϩάϥϜͱ͸ fun loadProfile(id: Int)
{ val profile = getProfile(id) showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ࣋ͭϓϩάϥϜͱ͸ ஞ࣮࣍ߦ fun loadProfile(id:
Int) { val profile = getProfile(id) showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ࣋ͭϓϩάϥϜͱ͸ ௨৴ॲཧ΍%#ΞΫηεɺॏ͍ͨܭࢉͳͲΛ ߦ͏৔߹ɺϒϩοΩϯάͯ͠͠·͏ɻ fun
loadProfile(id: Int) { val profile = getProfile(id) showProfile(profile) }

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ࣋ͭϓϩάϥϜͱ͸ fun getProfile(id: Int,
f: (Profile) -> Unit) fun loadProfile(id: Int) { val profile = getProfile(id) showProfile(profile) } ίʔϧόοΫΛड͚औΔܗʹͯ͠ʜ

f: (Profile) -> Unit) fun loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } } ϒϩοΩϯά͠ͳ͍ܗʹ͢Δ

f: (Profile) -> Unit) fun loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } }

f: (Profile) -> Unit) fun loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } } ؔ਺͸͜͜ͰҰ౓தஅ͍ͯ͠Δʂ

f: (Profile) -> Unit) fun loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } } ࠶։͍ͯ͠Δʜ

f: (Profile) -> Unit) fun loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } } ܧଓঢ়گΛ࣋ͭϓϩάϥϜͬ

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ༰қʹॻ͘ fun loadProfile(id: Int)
{ val profile = getProfile(id) showProfile(profile) }

{ val profile = getProfile(id).await() showProfile(profile) } ˞ٖࣅίʔυͰ͢

{ val profile = getProfile(id).await() showProfile(profile) } ˞ٖࣅίʔυͰ͢ HFU1SPpMFؔ਺͕ฦ͢ίϧʔν ϯʹ੍ޚΛ౉ࣗ͠਎͸தஅ͢Δ

{ val profile = getProfile(id).await() showProfile(profile) } ˞ٖࣅίʔυͰ͢ HFU1SPpMFؔ਺͕ฦ͢ίϧʔν ϯ͸ผͷεϨουͰಈ࡞͍ͯ͠ Δ͔΋͠Εͳ͍ͯ͠͠ͳ͍͔΋ ͠Εͳ͍

{ val profile = getProfile(id).await() showProfile(profile) } ˞ٖࣅίʔυͰ͢ HFU1SPpMFؔ਺͕׬ྃͨ͠Β஋ Λड͚औΔͱ͜Ζ͔Β࠶։

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گΛ༰қʹॻ͘ ίϧʔνϯ BTZODBXBJU fun
loadProfile(id: Int) { getProfile(token) { profile -> showProgile(profile) } } ίʔϧόοΫελΠϧ fun loadProfile(id: Int) { val profile = getProfile(id).await() showProfile(profile) } ˞ٖࣅίʔυͰ͢

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گ͕૿͑ͯ΋ fun loadProfile(id: Int)
{ getProfile(id) { profile -> getReport(profile.id) { report -> //.. } } } } } } ίʔϧόοΫελΠϧ

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓঢ়گ͕૿͑ͯ΋ ίϧʔνϯ BTZODBXBJU fun
loadProfile(id: Int) { val profile = getProfile(id).await() val report = getReport(profile.id).await() val a = getA().await() val b = getB().await() val c = getC().await() //… } ˞ٖࣅίʔυͰ͢

©2018 Lang-8 Inc. ALL Rights Reserved. wδΣωϨʔλɺετϦʔϜ wνϟϯωϧ wΞΫλʔϞσϧ wύΠϓϥΠϯ
wFUDʜ ܧଓঢ়گΛ؆୯ʹॻ͚Δ͜ͱͰ ࣮૷ָ͕ʹͳΔ΋ͷͨͪ

©2018 Lang-8 Inc. ALL Rights Reserved. wҰ࣌ఀࢭՄೳͳܭࢉͷΠϯελϯε wεϨουͷΑ͏ʹ࣮ߦ͢ΔίʔυϒϩοΫΛ࣋ͪɺಉ ༷ͷϥΠϑαΠΫϧΛ࣋ͪɺ࡞੒͞Εىಈ͞ΕΔ͕ɺ ಛఆͷεϨουʹଋറ͞Εͳ͍
w'VUVSF΍1SPNJTTͷΑ͏ʹɺԿΒ͔ͷ݁Ռ΍ྫ֎ ͕͋Δ৔߹͕͋Δ wܧଓঢ়گΛ࣋ͭϓϩάϥϜ͕༰қʹهड़Ͱ͖Δ ίϧʔνϯͱ͸ʜ

©2018 Lang-8 Inc. ALL Rights Reserved. ,PUMJO͸ͲͷΑ͏ʹ ίϧʔνϯΛ࣮ݱ͍ͯ͠Δͷ͔ʁ fun loadProfile(id:
Int) { val profile = getProfile(id).await() showProfile(profile) } )PX

©2018 Lang-8 Inc. ALL Rights Reserved. ίϧʔνϯΛεςʔτϚγϯʹ͢Δ fun simpleCoroutine() {
val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") }

val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ͜͜Ͱதஅ͢Δͱ͢Δ

val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ̎ͭͷঢ়ଶʹ෼ղͰ͖Δ ̎ͭͷঢ়ଶʹ෼ղͰ͖Δ

val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ̎ͭͷঢ়ଶʹ෼ղͰ͖Δ ԣஅతʹར༻͢Δม਺

©2018 Lang-8 Inc. ALL Rights Reserved. ίϧʔνϯΛεςʔτϚγϯʹ͢Δ class SimpleCoroutine {
var label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTimeMillis() println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.currentTimeMillis() - start}”) label++ } } } }

©2018 Lang-8 Inc. ALL Rights Reserved. ass SimpleCoroutine { var
label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } }

label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } } ̎ͭͷঢ়ଶΛ࣋ͭ ̎ͭͷঢ়ଶΛ࣋ͭ

©2018 Lang-8 Inc. ALL Rights Reserved. ݱࡏͷঢ়ଶΛ࣋ͭ ݱࡏͷঢ়ଶΛද͢ ass SimpleCoroutine
{ var label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } }

label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } } ݱࡏΛมԽͤ͞Δ

©2018 Lang-8 Inc. ALL Rights Reserved. ڞ௨ͯ͠࢖͏ม਺ ass SimpleCoroutine {
var label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } }

©2018 Lang-8 Inc. ALL Rights Reserved. ॲཧΛ࠶։͢Δؔ਺ ass SimpleCoroutine {
var label = 0 var start = 0L fun resume() { when (label) { 0 -> { start = System.currentTi println(“start") label++ delay(1000, this) } 1 -> { println("end ${System.cu label++ } } }

©2018 Lang-8 Inc. ALL Rights Reserved. fun delay(delayTime: Long, coroutine:
SimpleCoroutine) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() }

©2018 Lang-8 Inc. ALL Rights Reserved. fun delay(delayTime: Long, coroutine:
SimpleCoroutine) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() } ࠶։ͷͨΊʹ4JNQMF$PSPVUJOF Λड͚औ͓ͬͯ͘

©2018 Lang-8 Inc. ALL Rights Reserved. ࢦఆ͞Εͨ࣌ؒεϦʔϓͯ͠ 4JNQMF$PSPVUJOFΛ࠶։͢Δ fun delay(delayTime:
Long, coroutine: SimpleCoroutine) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() }

©2018 Lang-8 Inc. ALL Rights Reserved. val simpleCoroutine = SimpleCoroutine()
simpleCoroutine.resume() fun simpleCoroutine() { val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ίϧʔνϯ εςʔτϚγϯ

©2018 Lang-8 Inc. ALL Rights Reserved. val simpleCoroutine = SimpleCoroutine()
simpleCoroutine.resume() fun simpleCoroutine() { val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ίϧʔνϯ εςʔτϚγϯ TUBSU FOE TUBSU FOE

©2018 Lang-8 Inc. ALL Rights Reserved. εςʔτϚγϯͰίϧʔνϯΛ࣮ݱ͢Δ wதஅͱ࠶։Λঢ়ଶભҠͱݟཱͯΔ w࠶։ʹඞཁͳ৘ใΛεςʔτϚγϯ಺ʹ Ωϟϓνϟ͢Δ
w಺෦ঢ়ଶΛมԽͤ͞ͳ͕Β࣮ߦ͢Δ

©2018 Lang-8 Inc. ALL Rights Reserved. wίϧʔνϯΛϚʔΩϯά͢ΔͨΊʹTVTQFOEम ০ࢠΛಋೖ wϥϜμࣜʹTVTQFOEम০ࢠΛ෇༩͢Δͱίϧʔ νϯຊମΛද͢
TVTQFOEϥϜμ wؔ਺ʹ෇༩͢Δͱதஅ͢Δ৔ॴΛද͢ɻͦͷؔ਺Λ TVTQFOEؔ਺ͱݺͿ wTVTQFOEؔ਺͸TVTQFOEؔ਺ϥϜμ͔Β͔͠ ݺͼग़ͤͳ͍ TVTQFOEम০ࢠ

©2018 Lang-8 Inc. ALL Rights Reserved. wίϧʔνϯࣗ਎ΛܧଓΦϒδΣΫτʹ͢Δ wTVTQFOEؔ਺Λܧଓ౉͠ελΠϧ $POUJOVBUJPO1BTTJOH4UZMF $14
ʹม׵͢Δ wTVTQFOEؔ਺಺ͰܧଓΦϒδΣΫτΛऔΓ ग़ͯ͠೚ҙʹ࠶։Ͱ͖ΔΑ͏ʹ͢Δ ܧଓ

©2018 Lang-8 Inc. ALL Rights Reserved. TVTQFOEؔ਺ͱ$14 fun delay(delayTime: Long,
coroutine: SimpleCoroutine) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() }

©2018 Lang-8 Inc. ALL Rights Reserved. TVTQFOEؔ਺ͱ$14 suspend fun delay(delayTime:
Long) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() }

Long) { Thread { Thread.sleep(delayTime) coroutine.resume() }.start() } // c: Continuation<T> ίϯύΠϧ࣌ʹࣗಈͰ ܧଓΠϯλϑΣʔεͷ Ҿ਺͕૿͑Δ

Long) { // c: Continuation<T> suspendCoroutine<Unit> { c -> Thread { Thread.sleep(delayTime) c.resume(Unit) }.start() } }

Long) { // c: Continuation<T> suspendCoroutine<Unit> { c -> Thread { Thread.sleep(delayTime) c.resume(Unit) }.start() } } ܧଓΠϯλϑΣʔεΛऔΓग़͢ ͨΊʹ༻ҙ͞Ε͍ͯΔؔ਺

Long) { // c: Continuation<T> suspendCoroutine<Unit> { c -> Thread { Thread.sleep(delayTime) c.resume(Unit) }.start() } } ܧଓΠϯλϑΣʔεΛ࢖ͬͯ࠶։ ॲཧΛߦ͏

©2018 Lang-8 Inc. ALL Rights Reserved. TVTQFOEϥϜμͱίϧʔνϯ fun simpleCoroutine() {
val start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") }

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } }

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } } TVTQFOEϥϜμʹΑͬͯίϧʔνϯͷ ൣғ͕ܾ·Δɻ

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } f.startCoroutine(NoOpCompletion) }

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } f.startCoroutine(NoOpCompletion) } TVTQFOEϥϜμͷ֦ுؔ਺͕͍͔ͭ͘༻ ҙ͞Ε͍ͯΔɻTUBSU$PSPVUJOFؔ਺ʹΑͬ ͯίϧʔνϯΛ։࢝Ͱ͖Δ

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } f.startCoroutine(NoOpCompletion) } TUBSU$PSPVUJOFؔ਺͸$POUJOVBUJPO ΛҾ਺ʹऔΔɻίϧʔνϯ͕׬ྃͨ͠Βݺ ͼग़͞ΕΔ

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } f.startCoroutine(NoOpCompletion) } ৑௕ʹͳΔͨΊศ্ٓ༻ҙ ͨ͠Ϋϥε object NoOpCompletion<T> : Continuation<T> { override val context: CoroutineContext = EmptyCoroutineContext override fun resume(value: T) { // no op } override fun resumeWithException(exception: Throwable) { // no op }

val f: suspend () -> Unit = { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } f.startCoroutine(NoOpCompletion) } TUBSU FOE

©2018 Lang-8 Inc. ALL Rights Reserved. ίϧʔνϯϏϧμʔ fun simpleCoroutine() {
launch { val start = System.currentTimeMillis() println(“start") delay(1000) println("end ${System.currentTimeMillis() - start}”) } } ͦΕͧΕͷੑ࣭Λ΋ͭίϧʔνϯϏϧμʔ ͕ίϧʔνϯඪ४ϥΠϒϥϦͰఏڙ͞ΕΔ ͷͰීஈ͸ͦͪΒΛ࢖͏͜ͱʹͳΔɻ

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓΠϯλʔηϓλʔͱ ࣮ߦεϨου launch(CommonPool) {
// … } launch(UI) { // … } launch(JavaFx) { // … } launch(Swing) { // … } async(CommonPool) { // … }

©2018 Lang-8 Inc. ALL Rights Reserved. ܧଓΠϯλʔηϓλʔͱ ࣮ߦεϨου launch(CommonPool) {
// … } launch(UI) { // … } launch(JavaFx) { // … } launch(Swing) { // … } async(CommonPool) { // … } ίϧʔνϯϏϧμʔʹܧଓΠϯ λʔηϓλʔΛ౉࣮ͯ͠ߦεϨο υΛίϯτϩʔϧͰ͖Δ

©2018 Lang-8 Inc. ALL Rights Reserved. wίϧʔνϯΛεςʔτϚγϯʹม׵͠ ͍ͯΔ wม׵ͷͨΊʹTVTQFOEम০ࢠͱܧ ଓΛಋೖͨ͠
wܧଓΠϯλʔηϓλʔʹΑΓɺ࣮ߦͷ εϨουΛݶఆ͠ͳ͍ ,PUMJO͸ͲͷΑ͏ʹ ίϧʔνϯΛ+BWBͰ࣮ݱ͍ͯ͠Δͷ͔ʁ

©2018 Lang-8 Inc. ALL Rights Reserved. ֤छػೳ͸ϥΠϒϥϦͰఏڙ wDPSF SFBDUJWF OBUJWF
VJ KTͳͲ ͷϞδϡʔϧʹ෼͔Ε͍ͯΔ IUUQTHJUIVCDPN,PUMJOLPUMJOYDPSPVUJOFT

©2018 Lang-8 Inc. ALL Rights Reserved. ಛఆͷ؀ڥ޲͚ͷϥΠϒϥϦ΋͋Δ w"OESPJE +BWB'Y 4XJOH޲͚͕༻ҙ͞
Ε͍ͯΔ ܧଓΠϯλʔηϓλʔͷ࣮૷ IUUQTHJUIVCDPN,PUMJOLPUMJOYDPSPVUJOFTUSFFNBTUFSVJ

©2018 Lang-8 Inc. ALL Rights Reserved. ؀ڥߏங kotlin { experimental
{ coroutines 'enable' } } dependencies { implementation”org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.60" implementation “org.jetbrains.kotlinx:kotlinx-coroutines-core:0.24.0" // platformʹ߹Θͤͯ௥Ճ implementation “org.jetbrains.kotlinx:kotlinx-coroutines-android:0.24.0" } BQQCVJMEHSBEMF

©2018 Lang-8 Inc. ALL Rights Reserved. ؀ڥߏங kotlin { experimental
{ coroutines 'enable' } } dependencies { implementation”org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.60" implementation “org.jetbrains.kotlinx:kotlinx-coroutines-core:0.24.0" // platformʹ߹Θͤͯ௥Ճ implementation “org.jetbrains.kotlinx:kotlinx-coroutines-android:0.24.0" } BQQCVJMEHSBEMF ແͯ͘΋ಈ͚͘Ͳ*%&্ͱ ͔Ͱܯࠂ͕ͰΔ

©2018 Lang-8 Inc. ALL Rights Reserved. ࠷ॳͷίϧʔνϯ launch { val
start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") }

start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ίϧʔνϯϏϧμʔ

©2018 Lang-8 Inc. ALL Rights Reserved. w݁ՌΛ࣋ͨͳ͍ίϧʔνϯΛ࡞੒͢Δί ϧʔνϯϏϧμʔؔ਺ MBVODIؔ਺ public
fun launch( context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job

©2018 Lang-8 Inc. ALL Rights Reserved. MBVODIؔ਺ public fun launch(
context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ίϧʔνϯຊମɻ$PSPVUJOF4DPQFͷ֦ு TVTQFOEϥϜμ

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ίϧʔνϯͷ࣮ߦίϯςΩετɺڞ༗σʔ λ΍ܧଓΠϯλʔηϓλʔͳͲΛ͜͜Ͱࢦ ఆͰ͖Δ

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job

©2018 Lang-8 Inc. ALL Rights Reserved. %FGBVMU%JTQBUDIFS public actual val
DefaultDispatcher: CoroutineDispatcher = if (useCoroutinesScheduler) ExperimentalCoroutineDispatcher() else CommonPool

©2018 Lang-8 Inc. ALL Rights Reserved. %FGBVMU%JTQBUDIFS tcher() else CommonPool
εϨουϓʔϧΛ࢖ͬͯίϧʔνϯΛ࣮ߦ͢Δ ܧଓΠϯλʔηϓλʔɻ࣮ߦ؀ڥͷ$16ίΞ ਺ʹԠͯ͡εϨου਺͸มԽ͢Δ

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ίϧʔνϯͷ։࢝ํ๏Λࢦఆ͢ΔɻσϑΥ ϧτͰ͸ଈ࠲ʹ։࢝͢Δ

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ىಈͨ͠ίϧʔνϯͷ׬ྃΛ଴ͪ߹Θͤͨ ΓΩϟϯηϧͰ͖Δ

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ਌+PCΛઃఆ͢Δɻෳ਺ͷίϧʔνϯ ΛҰׅͰDBODFM͍ͨ࣌͠ͳͲʹ࢖͏

context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> Unit ): Job ίϧʔνϯͷ׬ྃΛίʔϧόοΫͰड͚औ Γ͍ͨ৔߹ʹࢦఆ͢Δ

start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") }

start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ඪ४ϥΠϒϥϦ͕ఏڙ͢Δ TVTQFOEؔ਺

start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } TUBSU FOE

©2018 Lang-8 Inc. ALL Rights Reserved. ίϧʔνϯͱ࣮ߦεϨου launch { val
start = System.currentTimeMillis() println("start") delay(1000) println("end ${System.currentTimeMillis() - start}") } ͲͪΒͷঢ়ଶ΋εϨουϓʔ ϧͰ࣮ߦ͞ΕΔ

©2018 Lang-8 Inc. ALL Rights Reserved. ྫ͑͹6*Λ৮ΔΑ͏ͳίϧʔνϯͩͱʜ launch { prograssBar.isVisible
= true delay(1000) prograssBar.isVisible = false }

©2018 Lang-8 Inc. ALL Rights Reserved. ྫ͑͹6*Λ৮ΔΑ͏ͳίϧʔνϯͩͱʜ launch { prograssBar.isVisible
= true delay(1000) prograssBar.isVisible = false } %FGBVMU%JTQBUDIFS͸εϨουϓʔ ϧͰίϧʔνϯΛ࣮ߦ͢Δ

= true delay(1000) prograssBar.isVisible = false } LPUMJOYDPSPVUJOFTBOESPJE͕ఏڙ͢Δ ܧଓΠϯλʔηϓλʔɻৗʹ6*εϨουͰ࠶։ ͢Δ

= true delay(1000) prograssBar.isVisible = false } 6*εϨουͰ࣮ߦ 6*εϨουͰ࣮ߦ

©2018 Lang-8 Inc. ALL Rights Reserved. BTZODBXBJU class Profile(val name:
String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true delay(1000) prograssBar.isVisible = false }

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true delay(1000) prograssBar.isVisible = false } ٖࣅతͳ௨৴ॲཧ

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = loadProfile() nameText.text = profile.name prograssBar.isVisible = false }

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = loadProfile() nameText.text = profile.name prograssBar.isVisible = false } ϒϩοΩϯά͢Δ

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } BTZODؔ਺Λ࢖͏

©2018 Lang-8 Inc. ALL Rights Reserved. w݁ՌΛ࣋ͭίϧʔνϯΛ࡞੒͢Δίϧʔ νϯϏϧμʔؔ਺ BTZODؔ਺ public
fun <T> async( context: CoroutineContext = DefaultDispatcher, start: CoroutineStart = CoroutineStart.DEFAULT, parent: Job? = null, onCompletion: CompletionHandler? = null, block: suspend CoroutineScope.() -> T ): Deferred<T>

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false }

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } ܧଓΛड͚औͬͯॲཧͷ׬ྃΛ଴ͭ

String = "Jack") fun loadProfile(): Profile { Thread.sleep(1000) return Profile() } launch(UI) { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } ඇಉظॲཧ͕׬ྃ͢Δͱɺ6*εϨο υͰܧଓΛ࠶։͢Δ

String = "Jack") fun loadProfile(): Profile { val profile = http.get(“http:/.”) return profile } launch(UI) { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false }

©2018 Lang-8 Inc. ALL Rights Reserved. ΤϥʔϋϯυϦϯά launch(UI) { ɹtry{
prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: Exception) { showError(e) } }

prograssBar.isVisible = true val token = async { getToken() } val profile = async { loadProfile(token.await()) }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: Exception) { showError(e) } }

prograssBar.isVisible = true val token = async { getToken() } val profile = async { loadProfile(token.await()) }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: Exception) { showError(e) } } ͜͜Ͱ͸தஅͤͣ։࢝ ͚͍ͩͯ͠Δ

prograssBar.isVisible = true val token = async { getToken() } val profile = async { loadProfile(token.await()) }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: Exception) { showError(e) } } ͜͜Ͱ݁ՌΛ଴͍ͬͯΔ

©2018 Lang-8 Inc. ALL Rights Reserved. ϦΫΤετΛฒྻͰ࣮ߦ͢Δ launch(UI) { ɹtry{
prograssBar.isVisible = true val profile = async { loadProfile() }.await() val articles = async { loadArticles() }.await() show(profile, articles) prograssBar.isVisible = false } catch (e: Exception) { showError(e) } }

prograssBar.isVisible = true val profile = async { loadProfile() }.await() val articles = async { loadArticles() }.await() show(profile, articles) prograssBar.isVisible = false } catch (e: Exception) { showError(e) } } ௚ྻͰ࣮ߦ͞Εͯ͠·͏

prograssBar.isVisible = true val profile = async { loadProfile() } val articles = async { loadArticles() } show(profile.await(), articles.await()) prograssBar.isVisible = false } catch (e: Exception) { showError(e) } }

prograssBar.isVisible = true val profile = async { loadProfile() } val articles = async { loadArticles() } show(profile.await(), articles.await()) prograssBar.isVisible = false } catch (e: Exception) { showError(e) } } ฒྻͰ։͓͍࢝ͯͯ͠ɺ଴ͪ߹Θͤ Δͱ͜ΖͰҰؾʹBXBJU͢Δ

©2018 Lang-8 Inc. ALL Rights Reserved. $BODFM val job =
launch(UI) { ɹtry { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: CancellationException) { // cancel } catch (e: Exception) { showError(e) } } //… job.cancel()

launch(UI) { ɹtry { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: CancellationException) { // cancel } catch (e: Exception) { showError(e) } } //… job.cancel() ίϧʔνϯΛىಈ͢Δͱ͖ʹ+PCΛ ड͚औ͓͚ͬͯ͹೚ҙͷλΠϛϯά ͰΩϟϯηϧ͕Ͱ͖Δ

launch(UI) { ɹtry { prograssBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name prograssBar.isVisible = false } catch (e: CancellationException) { // cancel } catch (e: Exception) { showError(e) } } //… job.cancel() Ωϟϯηϧͷྫ֎͕ඈΜͰ͘ΔͷͰ Ωϟον

©2018 Lang-8 Inc. ALL Rights Reserved. $BODFM "OESPJEͷྫ class MainActivity
: AppCompatActivity() { var job: Job? = null //… fun doSomething(){ job = launch(UI) { … } //… override fun onPause() { job?.cancel() super.onPause() } }

©2018 Lang-8 Inc. ALL Rights Reserved. $BODFM "OESPJEͷྫ class MainActivity
: AppCompatActivity() { var job: Job? = null //… fun doSomething(){ job = launch(UI) { … } //… override fun onPause() { job?.cancel() super.onPause() } } ϥΠϑαΠΫϧʹ߹Θͤ ͯΩϟϯηϧ

©2018 Lang-8 Inc. ALL Rights Reserved. ·ͱΊͯ$BODFM class MainActivity :
AppCompatActivity() { var rootJob: Job? = null //… fun doSomething(){ launch(UI, parent = rootJob) { … } fun doSomething2(){ launch(UI, parent = rootJob) { … } //… override fun onResume() { super.onResume() rootJob = Job() } override fun onPause() { rootJob.cancel() super.onPause() }

AppCompatActivity() { var rootJob: Job? = null override fun onResume() { super.onResume() rootJob = Job() } //… fun doSomething(){ launch(UI, parent = rootJob) { … } fun doSomething2(){ launch(UI, parent = rootJob) { … } //… override fun onPause() { rootJob.cancel() super.onPause() }

AppCompatActivity() { var rootJob: Job? = null override fun onResume() { super.onResume() rootJob = Job() } //… fun doSomething(){ launch(UI, parent = rootJob) { … } fun doSomething2(){ launch(UI, parent = rootJob) { … } //… override fun onPause() { rootJob?.cancel() super.onPause() } ·ͱΊͯΩϟϯηϧ

©2018 Lang-8 Inc. ALL Rights Reserved. ϦτϥΠ launch(UI) { try
{ progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false } catch (e: Exception) { showError(e) } }

©2018 Lang-8 Inc. ALL Rights Reserved. ϦτϥΠ launch(UI) { repeat(3)
{ try { progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false return@launch } catch (e: Exception) { if (!shouldRetry(e)) { return@repeat } } } showError() }

{ try { progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false return@launch } catch (e: Exception) { if (!shouldRetry(e)) { return@repeat } } } showError() } GPSจͱҰॹɻ͜Ε͸ί ϧʔνϯͰ͸ͳ͍ɻ

{ try { progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false return@launch } catch (e: Exception) { if (!shouldRetry(e)) { return@repeat } } } showError() } ੒ޭͨ͠ΒMBVODI͔Β ൈ͚Δ

{ try { progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false return@launch } catch (e: Exception) { if (!shouldRetry(e)) { return@repeat } } } showError() } ϦτϥΠ͢΂͖ΤϥʔͰͳ ͍ͳΒSFQFBUΛൈ͚Δ

{ try { progressBar.isVisible = true val profile = async { loadProfile() }.await() nameText.text = profile.name progressBar.isVisible = false return@launch } catch (e: Exception) { if (!shouldRetry(e)) { return@repeat } } } showError() } ϦτϥΠ͕શࣦͯഊ͔ͨ͠Ϧτϥ Π͢΂͖Ͱͳ͍Τϥʔ͕ൃੜ৔߹

©2018 Lang-8 Inc. ALL Rights Reserved. 3FUSPpUΛ%FGFSSFEԽ IUUQTHJUIVCDPN+BLF8IBSUPOSFUSPpULPUMJODPSPVUJOFTBEBQUFS +BLF8IBSUPO੡ɻ$BMM"EBQUFSΛ࣮૷ͯ͠%FGFSSFE Λฦ͢Α͏ʹ͍ͯ͠Δɻ
@POST("/api/v1/articles/{id}/like") fun like(@Path(“id") id: Long): Deferred<ResponseBody> @DELETE(“/api/v1/articles/{id}/like") fun likeCancel(@Path("id") id: Long): Deferred<ResponseBody> @POST(“/api/v1/users/sign_up”) fun signUp(@Body params: SignUpParameter): Deferred<SignInResponseEntity> @POST("/api/v1/users/sign_in") fun signIn(@Body params: SignInParameter): Deferred<SignInResponseEntity>

©2018 Lang-8 Inc. ALL Rights Reserved. &WFOU#VTͱ$IBOOFM class EventBus {
private val channel = BroadcastChannel<Any>(1) fun send(event: Any, context: CoroutineContext = DefaultDispatcher) { launch(context) { channel.send(event) } } fun subscribe(): ReceiveChannel<Any> = channel.openSubscription() inline fun <reified T> subscribeToEvent() = subscribe().filter { it is T }.map { it as T } } IUUQTHJTUHJUIVCDPNTWFOKBDPCTBCEEBCDEB

©2018 Lang-8 Inc. ALL Rights Reserved. &WFOU#VTͱ$IBOOFM val bus: EventBus
by inject() override fun onResume() { super.onResume() launch(UI, parent = rootJob) { bus.subscribeToEvent<LogoutEvent>().consumeEach { // logged out } } } override fun onPause() { rootJob.cancel() super.onPause() } //… bus.send(LogoutEvent)

©2018 Lang-8 Inc. ALL Rights Reserved. PO"DUJWJUZ3FTVMUΛTVTQFOE launch(UI) { val
result = activityResult(intent) if (result.isOk) { // ok val data: Intent? = result.flatMap() } else { // ng } } IUUQTHJUIVCDPNQEWSJF[FBOESPJEDPSPVUJOFT BOESPJEDPSPVUJOFTͱ͍͏αʔυύʔςΟϥΠϒϥϦ͕ ఏڙɻSFRVFTU1FSNJTTJPO΋͋ΔΑ

©2018 Lang-8 Inc. ALL Rights Reserved. w ܧଓঢ়گΛ࣋ͭϓϩάϥϜ͕༰қʹهड़Ͱ͖ͯศར w ,PUMJO͸ίϧʔνϯΛεςʔτϚγϯʹม׵࣮ͯ͠ݱ͠
͍ͯΔ w BTZODBXBJUͳͲͷ֤ػೳ͸,PUMJOͷެࣜϥΠϒϥϦ ͕ఏڙ͍ͯ͠Δ w MBVODIؔ਺ͱBTZODؔ਺Ͱେ఍଍ΓΔ w ඞཁʹԠͯࣗ͡෼Ͱίϧʔνϯͷ࢓૊ΈΛ࣮૷Ͱ͖Δɻ͢ ͰʹαʔυύʔςΟϥΠϒϥϦ͕͍͔ͭ͋͘Δ ,PUMJOίϧʔνϯ·ͱΊ

Rights Reserved. &OKPZ,PUMJO$PSPVUJOF

Rights Reserved. ͋Γ͕ͱ͏͍͟͝·ͨ͠

Kotlin コルーチンを 理解しよう

Kotlin コルーチンを 理解しよう

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Kotlin コルーチンを理解しよう

Kotlin コルーチンを理解しよう