Step up Kotlin

Transcript

1. Step up Kotlin! by miura(Paraya)
2. ࣗݾ঺հ ϓϥοτϑΥʔϜ - Android Java 2೥ - iOS 3೥ - Android Kotlin 1೥ ※New! ͦͷଞ - DDD 2೥
3. એ఻
4. Step up Kotlin!
5. KotlinΛ࢝ΊΔ্Ͱ৭ʑ೰Έ ͕͋Δͱࢥ͍·͢ɻ
6. ݟ׳Εͳ͍ίʔυ… letͬͯԿ… ʁͬͯԿ… ͦ΋ͦ΋Ͳ͏΍ͬͯಈ͍ͯΔ ͷ͔෼͔Βͳͯ͘ෆ҆
7. Ͱ͸KotlinΛ࢝ΊΔ্ͰɺͲ͏ ׳Ε͍ͯ͘ͷ͕͍͍ͩΖ͏͔
8. Javaख़࿅ऀ͕KotlinʹͲ͏׳Εͯ ͍͔͘ͷεςοϓΞοϓΛ঺հ͠ ·͢
9. ໨࣍ - Kotlinͷ঺հ - ॳ৺ऀ޲͚~JavaͬΆ͘KotlinΛॻ͘~ - ࣍ͷεςοϓ~Androidʹ༗༻ͳॴΛKotlin Β͘͠ॻ͘~
10. Kotlinͱ͸ Kotlin͸ҎԼͷϓϥοτϑΥʔϜ্Ͱಈ͖·͢ɻ - Kotlin for JVM - Kotlin for javascript - Kotlin for Native(ϕʔλ൛ɻMacɺWindowsͰ ಈ͘Β͍͠)
11. Kotlinͱ͸ ࠓͷͱ͜ΖJVMͷAndroidɺSpringͰͷ࠾༻ࣄ ྫΛଟ͘ฉ͖·͢ɻ ຊൃදͰ͸JVMͷதͰ΋Android޲͚ͷ࿩Λϝ ΠϯͰɻ
12. Kotlinͷྑ͍ͱ͜Ζ Null҆શͱ͔finalͱ͔ϓϩύςΟͱ͔ry ͱΓ͋͑ͣKotlinͰॻ͍͓͚ͯ͹ɺJavaͰॻ͘ ΑΓ΋਺ஈ্ͷ඼࣭ʹͳΔ͘Β͍ͷϙςϯγϟ ϧ͸͋Δɻ
13. KotlinͬͯͲ͏ಈ͍ͯΔͷʁ KotlinͰॻ͘ͱϏϧυ࣌ʹJavaͷίʔυʹม ׵͞Ε͍ͯ·͢ɻ
14. KotlinͬͯͲ͏ಈ͍ͯΔͷʁ // StringͷnameΛએݴ var name : String? name?.toInt() // Javaม׵ޙͷίʔυ if (name != null) { name.toInt(); } OVMMνΣοΫ͕ࣗಈੜ੒͞ΕΔ
15. ࠷ऴతʹJavaͱͯ͠ಈ͘ KotlinͰॻ͍ͯ΋݁ہ͸Javaͱͯ͠ಈ͘ɻ Kotlin͸Javaͷ໘౗ͳ෦෼Λٵऩͯ͠ΑΓϕ λʔͳJavaίʔυΛੜ੒͢Δɻ
16. ॳ৺ऀ޲͚ ~KotlinΛJavaΆ͘ॻ͘~
17. KotlinΛJavaΆ͘ॻ͘ class KotlinUser(val userId: String) ϓϥΠϚϦίϯετϥΫλ
    ΫϥεఆٛͱҰॹʹҾ਺PSม਺ఆ ٛͰ͖Δ
18. ϓϥΠϚϦίϯετϥΫλͱ ͔Α͘Θ͔Μͳ͍ͳ
19. ϓϥΠϚϦίϯετϥΫλΛ ࢖Θͳ͍ class KotlinUser { val userId: String constructor(userId: String) { this.userId = userId } } αϒίϯετϥΫλͰॳظԽ
    Ϗϧυ͸௨Γ·͢
    ˞XBSOJOH͸ग़·͢
20. KotlinΛJavaΆ͘ॻ͘ fun function(text: String?) { text?.let { it.toInt() } } ͸/VMMBCMF
    UZQF
    /VMMBCMF
    UZQFΛࢀর͢Δࡍ͸ MFU ౳Ͱ/PO/VMM
    UZQFͱͯ͠ࢀর͢Δ ඞཁ͕͋Δ
21. ?.letͱ͔Α͘Θ͔Μͳ͍ͳ
22. ?.letΛ࢖Θͳ͍ fun function(text: String?) { if (text != null) { text.toInt() } } /VMMBCMF
    UZQFΛࢀর͢Δࡍ͸ OVMMͰͳ͍จ຺Ͱ͋Ε͹0,
23. ·ͱΊ - JavaͬΆ͘ॻ͍ͯ΋େৎ෉ - KotlinΒ͠͞Λແཧʹ௥ٻ͠ͳͯ͘΋ NullSafetyͳͲͷKotlinͷओͳԸܙ͸े෼ड͚ ΒΕ·͢ - ؾܰʹKotlinΛॻ͍ͯΈΔ͜ͱ͕େࣄʂ
24. ࣍ͷεςοϓ ~Androidʹ༗༻ͳॴΛ KotlinΒ͘͠ॻ͘~
25. lazy private View view; View getView() { if (this.view == null) { return View.inflate(context, R.layout.view_top, null); } else { return this.view }
 }
26. lazy private View view; View getView() { if (this.view == null) { return LayoutInflater.from(context).inflate(R.layout.view_top, null); } else { return this.view }
 } private val view by lazy { LayoutInflater.from(context).inflate(R.layout.view_top, null); } MB[ZΛ༻͍Δ͜ͱͰɺϓϩύςΟࢀর࣌ʹॳظԽ͞Ε͍ͯ ͳ͍৔߹͚ͩॲཧΛߦ͏ͱ͍͏͜ͱ͕Ͱ͖Δ
27. apply Intent intent = new Intent(Intent.ACTION_PICK,MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
 intent.setType(“image/*”); // ͜͜ͰԿ͔͠Βͷॲཧ
 context.startActivity(intent); ͜͜ͷจ຺Ͱ͸JOUFOU͸ॳظԽࡁΈͷ΋ ͷ͕΄͍͠ɻ
    ͨͩϝιουԽ͢Δʹ͸ίετ͕ߴ͍ʜ
28. apply val intent = Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI).apply {
 type = "image/*"
 } // ͜͜ͰԿ͔͠Βͷॲཧ context.startActivity(intent) BQQMZΛར༻͢Δ͜ͱͰจ຺্ॳظԽࡁ ΈJOUFOUΛར༻Ͱ͖Δ
29. lateinit class View : RelativeLayout { private var name: String? = null // nullͰॳظԽ͠ͳ͍ͱΤϥʔ fun initView(name: String) { this.name = name } } ຊ౰͸OBNFΛ/POOVMMͱͯ͠ѻ͍͍͕ͨɺ7JFXͷॳ ظԽ͸ίϯετϥΫλͰ͸ͳ͘PO$SFBUF ͳͲ "OESPJEͷϥΠϑαΠΫϧʹͳΔͷͰΤϥʔʹͳͬͯ ͠·͏
30. lateinit class View : RelativeLayout { private lateinit var name: String fun initView(name: String) { this.name = name } } MBUFJOJUΛ෇͚Δ͜ͱͰɺॳظԽ͕ίϯετϥΫλ֎ ͰߦΘΕΔ͜ͱΛ໌ࣔͰ͖Δɻ
    ͨͩ͠ɺॳظԽ͠๨Εͨ৔߹͸ 6OJOJUJBMJ[FE1SPQFSUZ"DDFTT&YDFQUJPO͕ൃੜ
    
31. ·ͱΊ - Kotlin͸Javaʹม׵͞Εͯಈ͘ɻͭ·ΓJavaɻ - Kotlinͷຊ࣭͸NullSafetyͳͲʹ͋Γɺίʔυ ͷॻ͖ํ͸ඍʑͨΔ΋ͷͰ͢ɻ׳Εͳ͍಺͸ง ғؾͰॻ͍ͯ΋OK - lazyɺapplyɺlateinitΛ࢖͍͜ͳ͢͜ͱͰΑΓ KotlinΒ͘͠ͳΔ
32. ͝੩ௌ ͋Γ͕ͱ͏͍͟͝·ͨ͠