kanmoba-returns-02.pdf

Transcript

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

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   ࣗݾ঺հ

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

   Ltd. • App Team • ίϛοΫDAYS • δϟϯϓϧʔΩʔʂ • ΧΫϤϜ
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   ࣗݾ঺հ • Android • Kotlin • Flu-er • ! h-ps:/

   /blog.takuji31.jp • " h-ps:/ /nazuna.takuji31.jp • # $ h-ps:/ /photo.takuji31.jp
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   Kotlin Corou+nes

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   ࢖ͬͯ·͔͢ʁ

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   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

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   Corou%neʹ͍͓ͭͯ͞Β͍͠· ͠ΐ͏

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   suspended func*on

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    தஅՄೳͳؔ਺

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

    ωοτϫʔΫ௨৴ͳͲͷॏ͍ॲཧ return user }
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    Corou%neContext

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    Corou%neͷίϯςΩετ

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    ෳ਺ͷElementΛ૊Έ߹Θͤͯ࡞Δ

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    Job

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    Dispatcher

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    Name

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    Excep&onHandler

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    ωετՄೳ

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

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

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    Corou%neͷείʔϓ

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    ContextΛ࣋ͭ

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    ωετՄೳ

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

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

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

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    ϊϯϒϩοΩϯάͳFuture

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

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

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    ϗοτͳετϦʔϜ

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

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

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    ίʔϧυͳετϦʔϜ

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    Preview status

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    1.3.0-M1ͰExperimentalʹ

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

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