kanmoba-returns-02.pdf

Transcript

1. 5෼ͰΘ͔ͬͨؾʹͳΔKotlin Corou,nes @takuji31 ؼ͖ͬͯͨؔ੢ϞόΠϧΞϓϦݚڀձ #2

2. ࣗݾ঺հ

3. ࣗݾ঺հ • @takuji31 id:takuji31 • Takuji Nishibayashi • Hatena Co.,

   Ltd. • App Team • ίϛοΫDAYS • δϟϯϓϧʔΩʔʂ • ΧΫϤϜ

4. ࣗݾ঺հ • Android • Kotlin • Flu-er • ! h-ps:/

   /blog.takuji31.jp • " h-ps:/ /nazuna.takuji31.jp • # $ h-ps:/ /photo.takuji31.jp

5. Kotlin Corou+nes

6. ࢖ͬͯ·͔͢ʁ

7. ίϧʔνϯʢӳ: co-rou(neʣͱ͸ϓϩάϥ ϛϯάͷߏ଄ͷҰछɻαϒϧʔνϯ͕Τϯτ Ϧʔ͔ΒϦλʔϯ·ͰΛҰͭͷॲཧ୯Ґͱ͢ Δͷʹର͠ɺίϧʔνϯ͸͍ͬͨΜॲཧΛ தஅͨ͠ޙɺଓ͖͔ΒॲཧΛ࠶։Ͱ͖Δɻ — h$ps://ja.wikipedia.org/wiki/ %E3%82%B3%E3%83%AB%E3%83%BC%E3%83%81%E3%83%B3

8. Corou%neʹ͍͓ͭͯ͞Β͍͠· ͠ΐ͏

9. suspended func*on

10. தஅՄೳͳؔ਺

11. suspend function fetchUser() : User { val user = //

    ωοτϫʔΫ௨৴ͳͲͷॏ͍ॲཧ return user }

12. Corou%neContext

13. Corou%neͷίϯςΩετ

14. ෳ਺ͷElementΛ૊Έ߹Θͤͯ࡞Δ

15. Job

16. Dispatcher

17. Name

18. Excep&onHandler

19. ωετՄೳ

20. val context = Job() + Dispatchers.Main launch(context) { // run

    in main thread delay(100) val response = withContext(Dispatchers.Default) { // run in background thread networkAccess() } }

21. Corou%neScope

22. Corou%neͷείʔϓ

23. ContextΛ࣋ͭ

24. ωετՄೳ

25. async/launchͰ্ཱͪ͛ͨίϧʔν ϯ಺Ͱྫ֎͕ى͖Δͱείʔϓશମ ͕ࢮ͵ͷͰ஫ҙ

26. Ϋϥογϡ͢Δ΍ͭ // ྫ֎Ͱείʔϓશମ͕ࢮΜͰΫϥογϡ͢Δ coroutineScope { try { val user =

    async { fetchUser() } val series = async { fetchSeries("12345") } doSomething(user.await(), series.await()) } catch (e: IOException) { // catch͞Εͳ͍ } }

27. ରࡦ coroutineScope { try { // Nested scope val (user,

    series) = coroutineScope { val user = async { fetchUser() } val series = async { fetchSeries("12345") } Pair(user, series) } doSomething(user.await(), series.await()) } catch (e: IOException) { // show error } }

28. Deferred

29. ϊϯϒϩοΩϯάͳFuture

30. val user = async { fetchUser() } // Deferred<User> val

    series = async { fetchSeries("12345") } // Deferred<Series> doSomething(user.await(), series.await())

31. Channel

32. ϗοτͳετϦʔϜ

33. val channel = Channel<User>(Channel.CONFLATED) userObserver.addOnChangeListener { user -> launch {

    channel.send(user) } } channel.consumeEach { user -> doSomething(user) }

34. Flow

35. ίʔϧυͳετϦʔϜ

36. Preview status

37. 1.3.0-M1ͰExperimentalʹ

38. val userFlow = flow<User> { emit(observeUser()) } val seriesFlow =

    flow<Series> { emit(observeSeries()) } userFlow.combineLatest(seriesFlow) { user, series -> createItemModels(user, series) }.collect { itemModels -> // show items }

39. Enjoy Kotlin Corou.nes life!