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JavaからKotlinに さらにKotlinらしく書き換えることで コードがリファクタされて...
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Minami Baba
September 09, 2019
Programming
7.1k
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JavaからKotlinに さらにKotlinらしく書き換えることで コードがリファクタされていった話
Minami Baba
September 09, 2019
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Transcript
© DeNA Co., Ltd. +BWB͔Β,PUMJOʹ ͞Βʹ,PUMJOΒ͘͠ॻ͖͑Δ͜ͱͰ ίʔυ͕ϦϑΝΫλ͞Ε͍ͯͬͨ 1 2019 /
09 / 09 Kotlin Fest Reject Conference 2019 Minami Baba DeNA Co., Ltd.
© DeNA Co., Ltd. ࣗݾհ 2 • അೆ࣮ • DeNA
/ ϔϧεέΞࣄۀ • ʮา͍͓ͯτΫʯ • AndroidΞϓϦ։ൃ • @minami1389
© DeNA Co., Ltd. Google I/O 2019ʹͯᶃ • KotlinAndroid։ൃʹ͓͚Δਪݴޠʹ •
ʮ৽نϓϩδΣΫτͰKotlinͰ։ൃΛ࢝ΊΔ͖ʯ 3 ࢀরɿh5ps://www.youtube.com/watch?v=ldM6QZy9e0s
© DeNA Co., Ltd. Google I/O 2019ʹͯᶄ • ʮطଘϓϩδΣΫτΛKotlinʹҠߦ͢Δ͔Ͳ͏͔ ϓϩδΣΫτͱνʔϜͷঢ়گʹΑͬͯߟ͑Α͏ʯ
4 ࢀরɿh5ps://www.youtube.com/watch?v=ldM6QZy9e0s
© DeNA Co., Ltd. ʮา͍͓ͯτΫʯͰͷ༻ݴޠͷي 5 2016/04 ϦϦʔεɹ 2019/09 ݱࡏ
2018/07 KotlinҠߦ։࢝ Java:Kotlin = 100:0 Java:Kotlin = 50:50
© DeNA Co., Ltd. KotlinҠߦͷ͖͔͚ͬ 6 ʮKotlinҠߦͯ͠ΈΑ͏͔ͳʯ ʮίʔυΛͳΜ͔ϦϑΝΫλ͍ͨ͠ʯ
© DeNA Co., Ltd. ݱࡏͷײ Java͔ΒKotlinॻ͖͑ͯຊʹྑ͔ͬͨʂ ʰͳΜ͔ϦϑΝΫλ͍ͨ͠ʱͱ͍͏ͱ͖ʹ KotlinͷҠߦྑ͍બࢶͷҰͭͰ͢ ͦͷཧ༝ɾɾɾ ᶃ࢝ΊΔϋʔυϧ͕͍
ᶄ͔ͬ͠ΓޮՌΛಘΒΕΔ 7
© DeNA Co., Ltd. ࢝ΊΔϋʔυϧ͕ ͍ͬͯຊʁ ʢ4ͭͷෆ҆ʹ͓͑͠·͢ʣ 8
© DeNA Co., Ltd. ࢝ΊΔϋʔυϧ͕͍ͬͯຊʁᶃ ᶃJavaϑΝΠϧͨ͘͞Μ͋ΔͷͰ ɹશ෦ॻ͖͑ΔͳΜͯͦΜͳ࣌ؒऔΕͳ͍… → JavaͱKotlin͕ڞଘ͍ͯ͠Δঢ়ଶͰΞϓϦಈ͖·͢ 9
ᶄԿඦߦ͋ΔϑΝΠϧΛ1ߦͣͭॻ͖͑Δͷେมͦ͏… → Android Studio ͷࣗಈมػೳΛ͏͜ͱ͕Ͱ͖·͢
© DeNA Co., Ltd. ࢝ΊΔϋʔυϧ͕͍ͬͯຊʁᶄ ᶅ୯७ͳม͚ͩͩͱޮՌͳͦ͞͏ͩ͠·ͣ ɹKotlinΛ͔ͬ͠Γษڧ͠ͳ͍ͱ… → ୯७ͳม͚ͩͰޮՌ͋Γ·͢ʂ
10 ᶆKotlinΒ͍࣮ͬͯ͠ͳ͔ͳ͔ͦ͠͏… → ؆୯ʹಋೖ͍͚ͯ͠Δػೳ͋Γ·͢ʂ
© DeNA Co., Ltd. ୯७ͳมͰ ޮՌ͕ಘΒΕΔͬͯຊʁ ʢ۩ମྫΛ1͚ͭͩ͝հʣ 11
© DeNA Co., Ltd. ୯७ͳมͰಘΒΕΔޮՌ • ϝιουͷఆ͕͖ٛͬ͢Γ͢Δ • “public” /
“void” ͕লུͰ͖Δ • 7จࣈ * 5ϝιου/ * 240 = ؒͰ8,400จࣈઅ!! • ʮϝιουʹΓग़͖ͩ͢ͱ໘ͩͳʯ ͱ͍͏ѱຐͷʹউͭثʹͳΔ 12 Kotlin 11จࣈ Java 18จࣈ -7จࣈ
© DeNA Co., Ltd. ؆୯ʹऔΓೖΕΒΕΔ Kotlinػೳ͕͋Δͬͯຊʁ ʢ۩ମྫ1͚ͭͩ͝հʣ 13
© DeNA Co., Ltd. ؆୯ʹಋೖͰ͖ΔKotlinػೳ • anyϝιου • Ϧετʹ݅Λຬͨ͢ཁૉ͕͋Δ͔Λఆ •
࣮ͷҙਤ͕ඇৗʹ໌֬ʹͳΔ 14 any for in
© DeNA Co., Ltd. 15 ڧྗͳػೳͨ͘͞Μ͋Δ͚Ͳ ͪΓੵΕࢁͱͳΔΑ͏ͳ ࡉ͔͍ޮՌ,PUMJOͷັྗ
16 © DeNA Co., Ltd. ·ͱΊ KotlinΛ ͬͱ͖ʹͳΓ ίʔυΛͬͱ ͖Ε͍ʹ͠Α͏
© DeNA Co., Ltd. એ ٕज़ॻయͰຊΛग़͠·͢ ɾ !ା ʮ+BWBUP,PUMJO
ɹɹɹUP,PUMJO)BOECPPLʯ ɾࠓͷ֦େ൛ͷΑ͏ͳຊͰ͢ ɾ୯७ͳมͰಘΒΕΔޮՌ ɹ؆୯ʹಋೖͰ͖Δػೳ ɹͨ͘͞Μ͝հ͍ͯ͠·͢ 17 ৄͪ͘͜͠Β↓ h5ps://techbookfest.org/event/tbf07/circle/5733885484728320