iOSアプリ開発者から見たKotlin

2017/06/29
第6回Kotlin勉強会 ＠ Sansan
Koishi

Transcript

1. iOSΞϓϦ։ൃऀ͔Βݟͨ Kotlin 2017/06/29 ୈ6ճKotlinษڧձ ˏ Sansan Koishi Koichiro Oishi, 2017/6/29 1
2. ࣗݾ঺հ େੴ ߂Ұ࿠ γεςϜɾΞφϥΠζגࣜձࣾ iOSΞϓϦ։ൃऀ ΞΧ΢ϯτؔ࿈ * @mego_ * koishi Koichiro Oishi, 2017/6/29 2
3. ίϯςΩετ iOSΞϓϦΤϯδχΞͰ͢ɻ Objective-CͱSwift͸஌ࣝ͸͋Δ(͋Δఔ౓) JavaͳΜͱͳ͘஌ͬͯΔɻ Kotlin͸໊લͱͳΜͱͳ͘੝Γ্͕ΓΛɻ Koichiro Oishi, 2017/6/29 3
4. Kotlin͔Θ͍͍ ͱ͍͏͜ͱΛઌ೔ͷษڧձͰ஌Γ·ͨ͠ Koichiro Oishi, 2017/6/29 4
5. ͦͯ͠ SwiftͱࣅͯΔ ͱ͍͏͜ͱ΋ᷚͰ஌Γ·ͨ͠ Koichiro Oishi, 2017/6/29 5
6. ຊ೔͸ͦΜͳϨϕϧͰݟͨ KotlinͱSwiftͷҧ͍Λ ൃදͤͯ͞௖͖·͢ɻ Koichiro Oishi, 2017/6/29 6
7. ࢀߟจݙ Swift ࣮ફೖ໳ ஶऀͷ1ਓɺੴ઒͞Μ͔ΒαΠ ϯ΋Β͍·ͨ͠ɻ Koichiro Oishi, 2017/6/29 7
8. ࢀߟจݙ Kotlin ελʔτϒοΫ ௨শʮ੺΂͜ຊʯ ஶऀͷͨΖ͏͞Μ͔ΒαΠϯ ΋Β͍·ͨ͠ɻ Koichiro Oishi, 2017/6/29 8
9. ࢀߟจݙ ೖ໳·Ͱͷ Kotlin ॿ૸ಡຊ ࢲʹͱͬͯ΋ྑͦ͞͏Ͱ͢ ͪ͜ΒΛϕʔεʹSwiftͱൺֱ ͍͖ͯ͠·͢ Koichiro Oishi, 2017/6/29 9
10. ຊ୊Ͱ͢ɻ Koichiro Oishi, 2017/6/29 10
11. ΞδΣϯμ • جຊจ๏(ͬ͘͟Γ) • Null҆શ • ؔ਺, ΦϒδΣΫτ(γϯάϧτϯ), ίϯύχΦϯΦϒδΣΫτ(static) • σʔλΫϥε • Extension(֦ுؔ਺ɺ֦ுϓϩύςΟ) Koichiro Oishi, 2017/6/29 11
12. ͜ͷ͋ͨΓΛKotlinͱSwift Ͱൺֱͯ͠Έ·͢ Koichiro Oishi, 2017/6/29 12
13. جຊจ๏ - ม਺ͷએݴ1 Kotlin val num : Int = 1 var num2 : Int = 2 Swift let num: Int = 1 var num2: Int = 2 valͱlet͸ఆ਺ 1 Kotlinॿ૸ಡຊ p.28 Koichiro Oishi, 2017/6/29 13
14. جຊจ๏ - ม਺ͷએݴ Kotlin val num = 1 var num2 = 2 Swift let num = 1 var num2 = 2 ܕͷলུ(ܕਪ࿦) Koichiro Oishi, 2017/6/29 14
15. جຊจ๏ - whenࣜ2 Kotlin val value = 1 val str = when(value) { 1-> "one" 2-> "two" else -> "other" } 2 Kotlinॿ૸ಡຊ p.30 Koichiro Oishi, 2017/6/29 15
16. جຊจ๏ - whenࣜ Swift let value = 1 let str = { switch value { case 1: "one" case 2: "two" default: "other" } } Koichiro Oishi, 2017/6/29 16
17. Null҆શ - Nullෆڐ༰ܕ3 Kotlin var a: String = "abc" a = null // => ίϯύΠϧΤϥʔ Swift var a: String = "abc" a = nil // => ίϯύΠϧΤϥʔ 3 Kotlinॿ૸ಡຊ p.33 Koichiro Oishi, 2017/6/29 17
18. Null҆શ - Nullڐ༰ܕ Kotlin var b: String? = "abc" b = null // => OK Swift var b: String? = "abc" b = nil // => OK Koichiro Oishi, 2017/6/29 18
19. Null҆શ - Null νΣοΫͱ҆શͳݺͼग़͠ Kotlin Null ෆڐ༰ܕ΁ͷࢀর var a: String = "abc" val l : Int = a.length // => OK Null ڐ༰ܕ΁ͷࢀর var b: String? = "abc" val l : Int = b.length // => ίϯύΠϧΤϥʔ Koichiro Oishi, 2017/6/29 19
20. Null҆શ - Null ڐ༰ܕͷϝιουݺͼग़͠ Kotlin Null ෆڐ༰ܕ΁ͷࢀর var b: String? = "abc" val l : Int = if(b != null) b.length else -1 Null ڐ༰ܕ΁ͷࢀর val l : Int? = b?.length Koichiro Oishi, 2017/6/29 20
21. Null҆શ - Null ڐ༰ܕͷϝιουݺͼग़͠ Swift Null ෆڐ༰ܕ΁ͷࢀর var b: String? = "abc" let l: Int = b?.characters.count ?? -1 Null ڐ༰ܕ΁ͷࢀর let l: Int? = b?.characters.count Koichiro Oishi, 2017/6/29 21
22. Null҆શ - ΤϧϏεԋࢉࢠ Kotlin val l: Int = b?.length ?: -1 Swift let l: Int = b?.characters.count ?? -1 Koichiro Oishi, 2017/6/29 22
23. Null҆શ - !!ԋࢉࢠ Kotlin val l: Int = b!!.length b͕Null(nil)ͩͬͨΒ KotlinͰ͸NullPointerException͕ൃੜ Koichiro Oishi, 2017/6/29 23
24. Null҆શ - !!ԋࢉࢠ Swift let l: Int = b!.characters.count ڧ੍Ξϯϥοϓ b͕Null(nil)ͩͬͨΒ SwiftͰ͸Ϋϥογϡ͠·͢ Koichiro Oishi, 2017/6/29 24
25. Null҆શ - Swiftͷ৔߹ if let count = b?.characters.count { print(count) //ඇoptionalܕ } if letͷϒϩοΫ಺Ͱ͸Nullෆڐ༰ܕ(ඇoptionalܕ) ͱͯ͠࢖͑Δ Koichiro Oishi, 2017/6/29 25
26. Null҆શ - Swiftͷ৔߹ guard let count = b?.characters.count else { return } print(count) //ඇoptionalܕ guardจҎ߱Ͱ͸Nullෆڐ༰ܕ(ඇoptionalܕ)ͱ͠ ͯ࢖͑Δ Koichiro Oishi, 2017/6/29 26
27. ؔ਺4 Kotlin fun add(x: Int, y: Int): Int { return x + y } Swift func add(x: Int, y: Int) -> Int { return x + y } 4 Kotlinॿ૸ಡຊ p.36 Koichiro Oishi, 2017/6/29 27
28. ΦϒδΣΫτ(γϯάϧτϯ)5 Kotlin ఆٛ object DataProviderManager { fun registerDataProvider(provider: DataProvider) { // ... } } ݺͼग़͠ DataProviderManager.registerDataProvider(...) 5 Kotlinॿ૸ಡຊ p.47 Koichiro Oishi, 2017/6/29 28
29. ΦϒδΣΫτ(γϯάϧτϯ) Swift ఆٛ class DataProviderManager { static let sharedInstance = DataProviderManager() private init() { ... } func registerDataProvider(provider: DataProvider) { } } ݺͼग़͠ DataProviderManager.sharedInstance.registerDataProvider(...) Koichiro Oishi, 2017/6/29 29
30. ίϯύχΦϯΦϒδΣΫτ(static) Kotlin ఆٛ class MyClass { companion object Factory { fun create(): MyClass = MyClass() } } ݺͼग़͠ val instance = MyClass.create() Koichiro Oishi, 2017/6/29 30
31. ίϯύχΦϯΦϒδΣΫτ(static) Swift ఆٛ class MyClass { static func create() -> MyClass { return MyClass() } } ݺͼग़͠ let test = MyClass.create() Koichiro Oishi, 2017/6/29 31
32. σʔλΫϥε6 Kotlin data class Person(val id: Long, var name: String) Kotlinʹ͸Pair΍TripleͳͲ΋͋Δ͕ɺ ม਺໊͸͚ͭΒΕͳ͍ͬΆ͍ Swift typealias Person = (id: Int, name: String) σʔλΫϥε = ׬શʹSwiftͷλϓϧͰ΋ͳ͘ SwiftͷStructͬΆ͞΋͋Δʁ 6 Kotlinॿ૸ಡຊ p.52 Koichiro Oishi, 2017/6/29 32
33. Extension - ֦ுؔ਺(Extension Function)7 Kotlin fun String.appendBeer() : String = "${this}beer!" println("I like".appendBeer()) // => I like beer! Swift extension String { func appendBeer() -> String { return "\(self)beer!" } } print("I like".appendBeer()) 7 Kotlinॿ૸ಡຊ p.55 Koichiro Oishi, 2017/6/29 33
34. Extension - ֦ுϓϩύςΟ(Extension Properties) Kotlin ఆٛ val <T> List<T>.lastIndex: Int get() = size - 1 ݺͼग़͠ val arr = listOf(1,2,3) println(arr.lastIndex) //=> 2 Koichiro Oishi, 2017/6/29 34
35. Extension - ֦ுϓϩύςΟ(Extension Properties) Swift ఆٛ extension Array { var lastIndex: Int { return self.count - 1 } } ݺͼग़͠ let arr = [1,2,3] print(arr.lastIndex) //=> 2 Koichiro Oishi, 2017/6/29 35
36. ࠓճ͸͜͜·ͰͰ͕͢ɺ ͜Ε͔Β΋Kotlin΍͍͖ͬͯ·͢ ߴ֊ؔ਺ɾϥϜμɾΞΫηε੍ݶ͋ͨΓ΋ औΓ্͔͛ͨͬͨͷͰ͕͢ϘϦϡʔϜతʹ… Koichiro Oishi, 2017/6/29 36
37. SwiftΛ͋·Γ͝ଘ஌ͳ͍ํɺ ͍͔͕Ͱͨ͠Ͱ͠ΐ͏͔ Koichiro Oishi, 2017/6/29 37
38. Swift΋ ͔Θ͍͍ͷͰ͸? ͱݴͬͯΈ͔ͨͬͨͷͰ͢ Koichiro Oishi, 2017/6/29 38
39. ࠷ޙʹ Kotlinͷ͕͜͜ྑ͍ ͱ͔ڭ͍͑ͯͩ͘͞ʂ Koichiro Oishi, 2017/6/29 39
40. ͪͳΈʹ ͜ͷαΠτͰKotlinͱSwiftͷҧ ͍͕·ͱ·ͬͯ·͢Ͷɻ Swift is like Kotlin http://nilhcem.com/swift-is- like-kotlin/ Koichiro Oishi, 2017/6/29 40
41. ͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ɻ Koichiro Oishi, 2017/6/29 41