20171128_iOSLT_Swiftとイニシャライザ

Transcript

1. SwiftͱΠχγϟϥΠβ
   2017-11-28 @snakagam / Shota Nakagami
   

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2. ࿩͢಺༰
   4 Swiftͷجຊతͳ಺༰ʮΠχγϟϥΠβʯʹ͍ͭͯ
   4 ΠχγϟϥΠβͱܕͷؔ܎ʢΫϥεɺߏ଄ମɺྻڍମʣ
   4 ΠχγϟϥΠβͷछྨͱઆ໌
   

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3. ࣍ͷΩʔϫʔυ͕ϞϠͬͱ͍ͯ͠Δํʹ͓͢͢Ί!
   4 Failable Initilizer/ࣦഊՄೳΠχγϟϥΠβ
   4 Default Initializer/طఆΠχγϟϥΠβ
   4 Memberwise Initilaizer/શ߲໨ΠχγϟϥΠβ
   4 Designated Initializer/ࢦఆΠχγϟϥΠβ
   4 Convenience Initializer/؆қΠχγϟϥΠβ
   4 Required Initializer/ඞਢΠχγϟϥΠβ
   

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4. ΠχγϟϥΠβͱ͸
   4 ܕʢΫϥεɺߏ଄ମɺྻڍମʣͷΠϯελϯεΛॳظԽ
   ʢinitializeʣ͢Δಛघͳϝιουͷ͜ͱ
   4 AppleެࣜϦϑΝϨϯεʛInitialization
   init() {
   // ॳظԽ
   }
   

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5. ΠχγϟϥΠβͷه๏
   class MyClass {
   let a: Int
   // func͕ෆཁʢinitΩʔϫʔυͷΈʣ
   init(a: Int) {
   self.a = a
   }
   }
   let case1 = MyClass.init(a: 0)
   // ݺͼग़࣌͠ͷϝιου໊͕লུՄೳ
   let case2 = MyClass(a: 0)
   

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6. ͳͥॳظԽ͕ඞཁͳͷʁ
   ϓϩύςΟ͕ਖ਼͘͠ॳظԽͰ͖ͳ͍৔߹...
   4 ܕͷ੔߹ੑ͕औΕͳ͍
   4 ϝϞϦ҆શͰͳ͍ʢϝϞϦ֬อɺॳظԽʣ
   

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7. Swift͸҆શ
   C΍ObjC
   4 ڧҾʹ0΍falseɺNULLͰॳظԽʢόάͷݩʣ
   Swift
   4 ܕͷ੔߹ੑɺॳظԽ͸ίϯύΠϥʹΑͬͯ੩తʹνΣοΫ
   

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8. ίϯύΠϧΤϥʔͷྫ
   OptionalͰͳ͍ͷʹname͸࣮࣭nilʢܕͷෆ੔߹ʣ
   class Book {
   let name: String // ॳظԽ͞Ε͍ͯͳ͍
   init(name: String) {
   // ίϯύΠϧΤϥʔ
   // return from initializer without initializing all stored properties
   }
   }
   

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9. SwiftΫΠζ
   ͲͷϓϩύςΟΛॳظԽ͢Δඞཁ͕͋Δʁ!
   

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10. class MyClass {
    let a: Int
    let b: Int = 0
    let c: Int?
    let d: Int? = 0
    var e: Int
    var f: Int = 0
    var g: Int?
    var h: Int? = 0
    var i: Int { return 0 }
    var j: Int? { return 0 }
    init() {
    // ͲͷϓϩύςΟΛॳظԽ͢Δ???
    }
    }
    

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11. ਖ਼ղ͸...
    

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12. class MyClass {
    let a: Int // ॳظԽ͕ඞཁʂ
    let b: Int = 0
    let c: Int? // ॳظԽ͕ඞཁʂ
    let d: Int? = 0
    var e: Int // ॳظԽ͕ඞཁʂ
    var f: Int = 0
    var g: Int?
    var h: Int? = 0
    var i: Int { return 0 }
    var j: Int? { return 0 }
    init() {
    a = 0
    c = 0
    e = 0
    }
    }
    

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13. ΠχγϟϥΠβ಺ͰॳظԽͷཁ൱
    SwiftΫΠζͷ֤ϓϩύςΟΛ෼ྨ͢Δͱɾɾɾʁ
    

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14. // ʢෆཁʣίϯϐϡʔςουϓϩύςΟ
    var i: Int { return 0 }
    var j: Int? { return 0 }
    // ʢෆཁʣσϑΥϧτ஋͋ΓͷετΞυϓϩύςΟ
    let b: Int = 0
    let d: Int? = 0
    var f: Int = 0
    var h: Int? = 0
    // ʢෆཁʣOptionalܕͷม਺ετΞυϓϩύςΟ
    // ˒҉໧తʹnil͕σϑΥϧτ஋ͱͯ͠ઃఆ͞ΕΔ
    var g: Int?
    // ʢඞཁʣσϑΥϧτ஋ͳ͠ɺඇΦϓγϣφϧͷม਺ετΞυϓϩύςΟ
    var e: Int
    // ʢඞཁʣσϑΥϧτ஋ͳ͠ͷఆ਺ετΞυϓϩύςΟ
    let a: Int
    let c: Int?
    

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15. ม਺ϓϩύςΟͷ҉໧తͳnil୅ೖ
    4 σϑΥϧτ஋ͳ͠ͷOptionalͷετΞυϓϩύςΟʹؔ͠
    ͯ͸ఆ਺͔ม਺͔ʹΑͬͯڍಈ͕ҟͳΔ
    4 ม਺ͷ৔߹͸҉໧తʹnil͕୅ೖ͞ΕΔ
    4 ఆ਺͸nil͕୅ೖ͞Εͳ͍
    ʢ҉໧తʹnilΛ୅ೖͯ͠΋ɺมߋ͕Ͱ͖ͳ͍ͨΊʣ
    

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16. ॳظԽཁ൱Λ·ͱΊΔͱ...
    

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17. ॳظԽཁ൱ ϓϩύςΟछผ ิ଍આ໌
    ඞཁ σϑΥϧτ஋ͳ͠ɺఆ਺ετΞυ
    ϓϩύςΟ
    -
    ඞཁ σϑΥϧτ஋ͳ͠ɺඇΦϓγϣφ
    ϧͷม਺ετΞυϓϩύςΟ
    -
    - Optionalܕͷม਺ετΞυϓϩ
    ύςΟ
    ҉໧తʹnilͰॳظԽ͞ΕΔ
    - σϑΥϧτ஋͋ΓͷετΞυϓϩ
    ύςΟ
    σϑΥϧτ஋ͰॳظԽ͞ΕΔ
    - ίϯϐϡʔςουϓϩύςΟ ஋Λอ࣋͠ͳ͍ͷͰॳظԽ͕ෆ
    ཁ
    

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18. Ϋϥεɾߏ଄ମɾྻڍମ
    ڞ௨ͷΠχγϟϥΠβ
    

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19. ࣦഊՄೳΠχγϟϥΠβʛFailable
    Initilizer
    4 ॳظԽʹࣦഊ͢ΔՄೳੑͷ͋Δinitilizer
    4 ໭Γ஋͸OptionalܕʢॳظԽʹࣦഊͨ͠৔߹ʹnilΛฦ͢ʣ
    

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20. class WebPage {
    let title: String
    let url: URL
    init?(title: String, urlString: String) {
    // URLจࣈྻΛURLʹม׵Ͱ͖ͳ͍৔߹͸ॳظԽΛࣦഊͤ͞Δ
    guard let url = URL(string: urlString) else { return nil }
    self.title = title
    self.url = url
    }
    }
    

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21. طఆΠχγϟϥΠβʛDefault Initializer
    4 ϓϩύςΟͷॳظԽ͕ෆཁͳ৔߹ʹ҉໧తʹఆٛ͞ΕΔ
    

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22. class MyClass {
    var name: String = "MyClass"
    var number: Int = 0
    // ҉໧తʹinit()͕࣮૷͞ΕΔ
    }
    let myClass = MyClass()
    

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23. ߏ଄ମͷΠχγϟϥΠβ
    

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24. શ߲໨ΠχγϟϥΠβʛMemberwise Initilaizer
    4 structͰ҉໧తʹఆٛ͞ΕΔΠχγϟϥΠβ
    4 ϓϩύςΟ͕ଟ͍৔߹ʹɺΠχγϟϥΠβΛ࣮૷͢Δखؒ
    ͕ল͚Δ
    

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25. struct Book {
    let id: String
    let title: String
    var price: Int
    // ΠχγϟϥΠβ͸࣮૷͍ͯ͠ͳ͍
    }
    let book = Book(id: "001", title: "SwiftyBook", price: 1500)
    

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26. ྑ͍!!!
    

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27. ɺ͕ଞʹΠχγϟϥΠβͭ͘Δͱར༻ෆՄ!
    

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28. ɺ͕extentionͰճආՄ
    

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29. struct Book {
    let id: String
    let title: String
    var price: Int
    }
    // ಠࣗΠχγϟϥΠβΛextensionʹهࡌ
    extension Book {
    init() {
    id = "000"
    title = "λΠτϧͳ͠"
    price = 0
    }
    }
    let book1 = Book(id: "001", title: "SwiftyBook", price: 1500)
    let book2 = Book()
    

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30. ͨͩ͠ΞΫηεϨϕϧ͸internal
    ϥΠϒϥϦԽͱ͔ͰผϞδϡʔϧʹ͢ΔͱΞΫηεͰ͖ͳ͍ͷ
    Ͱ஫ҙ
    

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31. ྻڍମͷΠχγϟϥΠβ
    

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32. ྻڍମͷϝϯό໊ͰॳظԽ
    enum͸ετΞυϓϩύςΟΛ࣋ͨͳ͍ͨΊɺॳظԽ͸؆୯
    enum TrafficSignal {
    case green
    case yellow
    case red
    }
    let signal: TrafficSignal = .green
    

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33. ΧελϜΠχγϟϥΠβ
    4 ΠχγϟϥΠβ಺Ͱɺselfʹ஋Λ୅ೖ͢Δ
    enum TrafficSignal {
    case green
    case yellow
    case red
    init() {
    self = .red
    }
    }
    // .red
    let signal = TrafficSignal()
    

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34. raw value͕ఆٛ͞Ε͍ͯΔ৔߹
    ࣦഊՄೳΠχγϟϥΠβ͕҉໧తʹఆٛ͞ΕΔ
    enum TrafficSignal: String {
    case green
    case yellow
    case red
    // ࣦഊՄೳΠχγϟϥΠβ͕҉໧తʹఆٛ͞ΕΔ
    }
    let signal = TrafficSignal(rawValue: "yellow")
    

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35. ΫϥεͷΠχγϟϥΠβ
    

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36. ܧঝͷಛ௃Λ࣋ͭͨΊɺ֤Ϋϥε֊૚Ͱఆٛ͞ΕͨϓϩύςΟ
    ͕ॳظԽ͞ΕΔ͜ͱΛอূ͢Δඞཁ͕͋Δ
    

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37. ͦͷͨΊɺ֤ΠχγϟϥΠβͷϧʔϧ͕͍Ζ͍Ζ
    4 ࢦఆΠχγϟϥΠβ
    4 ؆қΠχγϟϥΠβ
    

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38. ࢦఆΠχγϟϥΠβʛDesignated Initializer
    4 ඞਢͷΠχγϟϥΠβ
    4 શͯͷετΞυϓϩύςΟΛॳظԽ͢Δ
    4 ܧঝ͍ͯ͠Δ৔߹͸ɺॳظԽޙʹεʔύʔΫϥεͷࢦఆΠ
    χγϟϥΠβΛݺͿ
    

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39. class Book {
    let title: String
    let price: Int
    // ࢦఆΠχγϟϥΠβ
    init(title: String, price: Int) {
    self.title = title
    self.price = price
    }
    }
    class Ebook: Book {
    var urlString: String
    // ࢦఆΠχγϟϥΠβ
    init(title: String, price: Int, urlString: String) {
    self.urlString = urlString
    super.init(title: title, price: price)
    }
    }
    

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40. ؆қΠχγϟϥΠβʛConvenience Initializer
    4 ඞਢͰͳ͍ʢॳظԽॲཧΛศརʹ͢ΔͨΊͷΠχγϟϥΠ
    βʣ
    4 ࢦఆΠχγϟϥΠβΛϥοϓ͠ɺ಺෦ͰݺͿ
    4 ಉҰΫϥεͷΠχγϟϥΠβΛݺͼɺ࠷ऴతʹࢦఆΠχγ
    ϟϥΠβΛݺΜͰ΋OK
    4 ࠷ऴతʹࢦఆΠχγϟϥΠβͰॳظԽ͢Δඞཁ͕͋Δͨ
    Ίɺఆ਺ϓϩύςΟ͸؆қΠχγϟϥΠβͰॳظԽͰ͖ͳ
    

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41. class Book {
    let title: String
    let price: Int
    // ࢦఆΠχγϟϥΠβ
    init(title: String, price: Int) {
    self.title = title
    self.price = price
    }
    }
    class Ebook: Book {
    var urlString: String
    // ࢦఆΠχγϟϥΠβ
    init(title: String, price: Int, urlString: String) {
    self.urlString = urlString
    super.init(title: title, price: price)
    }
    // ؆қΠχγϟϥΠβ
    convenience init(title: String, price: Int, url: URL) {
    self.init(title: title, price: price, urlString: url.absoluteString)
    }
    }
    

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42. Πϝʔδਤ
    ֤Ϋϥε֊૚ͰॳظԽ͕ߦΘΕΔྲྀΕ
    

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44. ඞਢΠχγϟϥΠβʛRequired Initializer
    4 requiredΩʔϫʔυͷ͍ͭͨΠχγϟϥΠβ͕͋Δ৔߹ɺ
    αϒΫϥεͰͷ࣮૷͕ඞਢͱͳΔ
    4 αϒΫϥεଆͰ͸overrideͷهड़͸ෆཁͰrequiredͷΈه
    ड़͢Δʢࣗ໌ͳͨΊʣ
    

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45. class MyView: UIView {
    // ࢦఆΠχγϟϥΠβ
    override init(frame: CGRect) {
    super.init(frame: frame)
    }
    // ؆қΠχγϟϥΠβ
    convenience init() {
    self.init(frame: .zero)
    }
    // ඞਢΠχγϟϥΠβ
    required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    }
    }
    

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46. ϓϩτίϧͰΠχγϟϥΠβΛఆٛͨ͠৔߹ɺͦͷϓϩτίϧ
    ʹ४ڌ͢ΔΫϥεͰͷΠχγϟϥΠβ࣮૷͸ඞਢΠχγϟϥΠ
    βͱͳΔ
    protocol MyProtocol {
    var stringValue: String { get set }
    // required͸ࢦఆ͍ͯ͠ͳ͍
    init(intValue: Int)
    }
    class MyClass: MyProtocol {
    var stringValue: String
    // required͕ඞཁ
    required init(intValue: Int) {
    stringValue = String(intValue)
    }
    }
    

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47. ͋·Γ࢖Θͳ͍͔΋
    

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48. ·ͱΊ
    

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49. ར༻Մೳͳܕ छผ આ໌
    ڞ௨ Failable Initilizer/ࣦഊՄೳΠχγϟϥΠβ ॳظԽʹࣦഊ͢ΔՄೳੑͷ͋ΔΠχγϟϥ
    Πβ
    ڞ௨ Default Initializer/طఆΠχγϟϥΠβ ॳظԽ͕ෆཁͳ৔߹ʹ҉໧తʹ࣮૷͞ΕΔ
    ΠχγϟϥΠβ
    ߏ଄ମ Memberwise Initilaizer/શ߲໨Πχγϟϥ
    Πβ
    ߏ଄ମͰશͯͷετΞυϓϩύςΟΛॳظԽ
    ͢ΔΑ͏҉໧తʹ࣮૷͞ΕΔΠχγϟϥΠ
    β
    Ϋϥε Designated Initializer/ࢦఆΠχγϟϥΠ
    β
    શͯͷετΞυϓϩύςΟΛॳظԽ͠ɺ਌Ϋ
    ϥε͕͋Ε͹਌ΫϥεͷࢦఆΠχγϟϥΠβ
    Λ࣮ߦ͢ΔɺඞਢͷΠχγϟϥΠβ
    Ϋϥε Convenience Initializer/؆қΠχγϟϥΠ
    β
    ࢦఆΠχγϟϥΠβΛϥοϓ͢Δɺ೚ҙͷΠ
    χγϟϥΠβ
    ྻڍମ Required Initializer/ඞਢΠχγϟϥΠβ αϒΫϥεͰͷΠχγϟϥΠβͷ࣮૷Λඞਢ
    ͱ͢ΔΠχγϟϥΠβ
    

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50. ࢀߟ
    4 Swift࣮ફೖ໳ʢhttp://gihyo.jp/book/
    2017/978-4-7741-8730-3ʣ
    4 ৄղSwiftʢhttp://www.sbcr.jp/products/
    4797390537.htmlʣ
    4 ͠Ίḉ೔هʛSwiftͷϓϩύςΟʔͱॳظԽͱ
    Convenience initializer
    

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51. ͓ΘΓ
    ͋Γ͕ͱ͏͍͟͝·ͨ͠!!!
    

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