Java で書かれた Android アプリを Kotlin で書き直すまでの話 / Talk of rewrite Android app for Java to Kotlin

集まれ Kotlin 好き ! Kotlin 愛好会 vol 2 @ DeNA

Transcript

1. +BWBͰॻ͔Εͨ"OESPJEΞϓϦΛ

   ,PUMJOͰॻ͖௚͢·Ͱͷ࿩
   ू·Ε,PUMJO޷͖,PUMJOѪ޷ձWPM
   

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2. ٶԼཽେ࿠
   $IBU8PSLגࣜձࣾ
   ΫϥΠΞϯτΞϓϦέʔγϣϯ։ൃ෦
   !SZVHPP@
   ޷͖ͳ,PUMJOͷػೳ͸4NBSU$BTU
   

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3. $IBU8PSL
   

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4. $IBU8PSL
   ‣ Ϗδωε޲͚ͷνϟοταʔϏε
   8FCJ04"OESPJEσεΫτοϓΞϓϦͰఏڙ
   "OESPJEΞϓϦ͸೥຤͔Β+BWB੡
   ‣ ʙ·Ͱ͸5JUBOJVN +BWB4DSJQU
   ੡ͩͬͨ
   ‣ +BWB൛͸͔Β։ൃΛ։࢝
   ‣ ,PUMJOΛݕ౼͢ΔͨΊʹͷ,PUMJOษڧձʹࢀՃ
   ‣ ࠾༻ڧԽத
   J04"OESPJE4DBMB1)143&ͳͲ
   ৄ͘͠͸8FCαΠτͰ
   ‣ IUUQTDPSQDIBUXPSLDPNKBSFDSVJU
   ‣ ؾʹͳΔ͜ͱ͕͋ͬͨΒ੠͔͚ͯԼ͍͞
   

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5. ,PUMJO
   

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6. ,PUMJO
   ‣ (PPHMF*0Ͱ"OESPJEެࣜݴޠԽ
   ͦΕ·Ͱ΋,PUMJOͷ։ൃࣄྫ͸ଟ͋ͬͨ͘
   ެࣜݴޠʹͳΔ͜ͱͰ҆৺ΛखʹೖΕͨ
   طଘͷΞϓϦͱͷ෇͖߹͍ํΛͲ͏͢Δ͔ʁ
   ‣ ෦෼తʹಋೖPSશ໘తʹಋೖ
   ͜Εͱ͍ͬͨਖ਼ղ͸ͳ͍
   ৽نϓϩδΣΫτͳΒ͹,PUMJOͰྑ͍
   $IBU8PSLͰ͸શ໘తͳಋೖΛܾఆͨ͠
   

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7. Ͳ͔͜Β
   ‣ ಋೖ౰ॳ͸શ໘తͳಋೖ༧ఆ͸ͳ͔ͬͨ
   খ͞ͳμΠΞϩά͔ͭΒಋೖΛ։࢝
   ‣ (PPHMF*0ͷཌ೔͔Βελʔτ
   
   ࣍ʹطଘͷը໘Λͭॻ͖׵͑ͯΈͨ
   ৽͍͠ػೳͷ௥ՃΛ,PUMJOͰॻ͍ͯΈͨ
   ‣ +BWBͱͷͭͳ͗ࠐΈ͕ωοΫʹͳ͍ͬͯͬͨ
   ͔֬ʹ,PUMJO͸+BWBͱͷ࿈ܞ͸όονϦͰ͖Δ
   ͏·͘࿈ܞ͢Δʹ͸ಛผͳҙࣝ෇͚͕ඞཁ
   ‣ !+WN'JFME!+WN4UBUJD!+WN0WFSMPBET
   ‣ SFUVSO6OJU*/45"/$&
   ‣ 1MBUGPSN5ZQFT
   

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8. !+WNʙΞ
   ϊςʔγϣϯ
   ‣ +BWB͔ΒͷΞΫηεΛҙࣝ͢Δඞཁ͕͋Δ
   class MyFragment : Fragment() {
   companion object {
   @JvmField
   val TAG: String =
   MyFragment::class.java.simpleName
   }
   @JvmOverloads
   fun logic(label: String = "") {}
   } ,PUMJO
   

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9. SFUVSO6OJU*/45"/$&
   ‣ ,PUMJOʹ͸lWPJEz͸ଘࡏ͠ͳ͍
   class BusinessLogic {
   fun async(callback: () -> Unit) {
   // Some async logic
   callback();
   }
   }
   BusinessLogic logic = new BusinessLogic();
   logic.async(() -> {
   return Unit.INSTANCE;
   });
   ,PUMJO
   +BWB
   

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10. IUUQTEJTDVTTLPUMJOMBOHPSHUKBWBJOUFSPQVOJUDMPTVSFTSFRVJSFEUPSFUVSOLPUMJOVOJU
    !+WN7PJEͷఏҊ
    ೥ʹಉ͡໰୊ఏى
    

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11. 1MBUGPSN5ZQFT
    ‣ /PO/VMM͔/VMMBCMF͔એݴ͞Ε͍ͯͳ͍ܕ
    ܕ৘ใΛݟΔͱlzϚʔΫ͕෇͍͍ͯΔ
    ‣ "OESPJE4%,͸جຊతʹ1MBUGPSN5ZQFT
    ‣ !/PO/VMM!/VMMBCMF͕෇͍ͯͨΒϥοΩʔ
    

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12. 1MBUGPSN5ZQFT
    ‣ "OESPJE4%,Ͱ͋Ε͹ίʔυΛಡΜͰܕΛܾఆ͢Δ
    val inflater: LayoutInflater =
    LayoutInflater.from(this) ,PUMJO
    

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13. ,PUMJOͷ͏·ຯΛҾ͖ग़͍ͨ͠
    ‣ ,PUMJOΛ෦෼తʹಋೖ͢Δͱ+BWBʹ΋Өڹ͕ग़Δ
    ٯʹ+BWBͷ࣮૷͕,PUMJOʹ΋Өڹ͢Δ
    ‣ +BWB0QUJPOBMWT,PUMJO/PO/VMM/VMMBCMF5ZQF
    ࣗ෼ୡ͕ॻ͍ͨ+BWBͷίʔυΛݟฦ͢
    ‣ !/PO/VMM!/VMMBCMFΞ
    ϊςʔγϣϯΛ෇͚͍ͯ͘ʁ
    ‣ ͍ͬͦͷ͜ͱ,PUMJOʹஔ͖׵͑ͨํ͕ྑ͍ͷͰ͸ͳ͍͔ʁ
    ‣ ͭͣͭஸೡʹ,PUMJOԽΛਐΊ͍ͯ͘
    ਓͷνʔϜ಺Ͱ΋,PUMJOͷशख़౓͸όϥόϥ
    ૬ޓʹϨϏϡʔΛ͠ͳ͕ΒཧղΛਂΊ͍ͯ͘
    1VMM3FRVFTUʹ,PUMJOͷݴޠػೳͷઆ໌Λॻ͘
    

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14. ,PUMJOͷ͏·ຯΛҾ͖ग़͢ಓఔ
    
    (PPHMF*0b
    
    $IBU8PSL"OESPJE

    7FSTJPO
    'VMM+BWB ߦ
    
    $IBU8PSL"OESPJE

    7FSTJPO
    'VMM,PUMJO ߦ
    Ի੠௨࿩ "OESPJE
    ߦ
    

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15. ,PUMJOͷ͏·ຯΛҾ͖ग़ͨ݁͠Ռ
    ‣ ϲ݄ͰશͯͷίʔυΛ,PUMJOԽͨ͠
    ͦͷؒʹػೳ௥Ճ΍ϦϑΝΫλϦϯά΋Ͱ͖ͨ
    ,PUMJOԽલޙͰίʔυͷྔ͸ʹͳͬͨ
    ‣ νʔϜ΁ͷਁಁͱޮՌ
    /VMM1PJOUFS&YDFQUJPOͷ๾໓
    ‣ ΄΅ग़ձ͍ͬͯͳ͍
    ‣ 1MBUGPSN5ZQFTͷऔΓѻ͍͕పఈ͞Εͨ
    ‣ +BWBͷ0QUJPOBMΑΓ΋औΓѻָ͍͕
    ίʔυͷՄಡੑͷ޲্
    ‣ جຊ͸WBMͰڱ͍ൣғͰWBSΛ࢖͏ͳͲͷҙࣝ෇͚
    

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16. ,PUMJOͷ͏·ຯΛҾ͖ग़ͨ͢Ίʹ
    ‣ ,PUMJOଆͷ࣮૷΋ݟͨํ͕ྑ͍
    ྫ͑͹NBQˠUP-JTUͷྲྀΕ
    ‣ +BWBͷ4USFBNΛ࢖ͬͯΔͱ͍ͭ΍Γͨ͘ͳΔ
    ‣ ࣮ࡍ͸NBQͷ࣌఺Ͱ-JTU3͕ಘΒΕΔ
    val results: List = someCollection
    .map { it.convert() }
    .toList() ,PUMJO
    

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17. ,PUMJOͷ͏·ຯΛҾ͖ग़ͨ͢Ίʹ
    ‣ 4IPX,PUMJO#ZUFDPEFˠ%FDPNQJMF͢Δ
    val source = listOf(1, 2, 3, 4, 5)
    val results: List = source
    .map { it.toString(10) } ,PUMJO
    UP-JTUແ
    UP-JTU༗
    

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18. ,PUMJOͷ͏·ຯΛҾ͖ग़͠ଛͶͨࣄྫ
    ‣ ,PUMJOͱ"OESPJE +%,
    ͷ"1*͕ಉ໊͡લ
    ‣ ਖ਼ղ͸൪ԼͷGPS&BDIͰͨ͠ʂ
    ൪Լ͸LPUMJODPMMFDUJPOTGPS&BDI
    ‣ .BQͷ֦ுؔ਺ͱͯ͠ఆٛ͞Ε͍ͯΔ
    ্͔ΒͭΊ͸KBWBVUJM.BQGPS&BDI
    ‣ "OESPJEͰ࢖͑ΔΑ͏ʹͳͬͨͷ͸-W͔Β
    ‣ /P$MBTT%FG'PVOE&SSPS͕ൃੜͨ͠
    

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19. ࠷ޙʹ
    

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20. ࠷ޙʹ
    ‣ طଘͷΞϓϦ΋ஈ֊తʹ,PUMJOԽ͍͚ͯ͠Δ ͨ
    
    +BWBͱͷ૬ޓӡ༻ੑͷߴ͞
    ‣ த్൒୺ʹಋೖ͢Δ͙Β͍ͳΒ͹શͯॻ͖׵͍͑ͨ
    +BWBͱ,PUMJOؒͰͦΕͧΕΛҙࣝ͢Δखؒ
    ‣ ਓखͰؾΛ͚ͭͳ͍ͱ͍͚ͳ͍Օॴ͸ඞͣࣄނ͕ੜ·ΕΔ
    ‣ ଞνʔϜ͔Βݟͨ৺ཧతোน͕Լ͕ͬͨ
    ෭࣍తͳޮՌ
    ‣ J04νʔϜ͕,PUMJOͷίʔυΛಡΜͰ4XJGUʹҠ২
    ‣ 4DBMB ؚ4DBMB+4
    5ZQF4DSJQU࢖͍΋༰қʹಡΊΔ
    

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21. ͓͠·͍
    

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