iOS & Android & Swift & Kotlin (Video)

Android and iOS development tools have consistently converged over the past few years. The arrival of Kotlin as a second officially supported language for Android development is perhaps the most significant example of this to date.

Kotlin and Swift were designed independently but share many foundational principles. In this talk, I compare and contrast these exciting languages and show you just how similar their implementations are. I also demonstrate how shared architectures and layout design tool evolution have further aided cross platform parity.

If you’re a cross-platform curious iOS developer, then this talk’s for you! There’s never been a better time to widen your horizons.

Video: https://youtu.be/hylwSuqSJ_E
Venue: Motor City CocoaHeads

Transcript

1. @skentphd iOS & Android & Swift & Kotlin
2. @skentphd Who? Stuart Kent stkent.com @skentphd http://bit.ly/cocoaheads-july-2017
3. @skentphd Who? Stuart Kent stkent.com @skentphd http://bit.ly/cocoaheads-july-2017
4. @skentphd ! What?
5. @skentphd $ What Not?
6. @skentphd Why?
7. @skentphd For common topics: • Illustrate similarities by comparing code. • Discuss differences and mitigation strategies. Recommend resources & tactics. Q&As. How?
8. @skentphd • Languages • Architecture • Layouts Topics
9. @skentphd • Application lifecycle • Networking • Continuous Integration • Distribution • Soft Skills ❤ Not Topics
10. @skentphd • IDEs (mostly) • Frameworks Also Not Topics
11. @skentphd Level Check
12. @skentphd Me Android Java Kotlin iOS Objective-C Swift
13. @skentphd You? iOS Objective-C Swift Android Java Kotlin
14. @skentphd Languages
15. @skentphd Principles • Safe • Expressive • Concise • Multi-paradigm • Fast • Interoperable
16. @skentphd Principles • Safe • Expressive • Concise • Multi-paradigm • Fast • Interoperable
17. @skentphd Syntax & Capabilities
18. @skentphd Swift 4 class User { let first: String let last: String? init( first: String, last: String? = nil) { self.first = first self.last = last } } class User { val first: String val last: String? constructor( first: String, last: String? = null) { this.first = first this.last = last } } Kotlin 1.1.3
19. @skentphd Swift class User { let first: String let last: String? init( first: String, last: String? = nil) { self.first = first self.last = last } } class User { val first: String val last: String? constructor( first: String, last: String? = null) { this.first = first this.last = last } } Kotlin
20. @skentphd Swift class User { let first: String let last: String? init( first: String, last: String? = nil) { self.first = first self.last = last } } class User { val first: String val last: String? constructor( first: String, last: String? = null) { this.first = first this.last = last } } Kotlin
21. @skentphd Swift class User { let first: String let last: String? init( first: String, last: String? = nil) { self.first = first self.last = last } } class User { val first: String val last: String? constructor( first: String, last: String? = null) { this.first = first this.last = last } } Kotlin
22. @skentphd Swift class User { let first: String let last: String? init( first: String, last: String? = nil) { self.first = first self.last = last } } class User { val first: String val last: String? constructor( first: String, last: String? = null) { this.first = first this.last = last } } Kotlin
23. @skentphd Swift let stuart = User(first: "stuart", last: "kent") Kotlin val stuart = User(first = "stuart", last = "kent")
24. @skentphd Swift let stuart = User(first: "stuart", last: "kent") stuart.first // "stuart" Kotlin val stuart = User(first = "stuart", last = "kent") stuart.first // "stuart"
25. @skentphd Swift let stuart = User(first: "stuart", last: "kent") stuart.first // "stuart" stuart.last // "kent" Kotlin val stuart = User(first = "stuart", last = "kent") stuart.first // "stuart" stuart.last // "kent"
26. @skentphd Swift let stuart = User(first: "stuart", last: "kent") stuart.first // "stuart" stuart.last // "kent" "\(stuart.first) \(stuart.last)" // "stuart Optional("kent")" Kotlin val stuart = User(first = "stuart", last = "kent") stuart.first // "stuart" stuart.last // "kent" "${stuart.first} ${stuart.last}" // "stuart kent"
27. @skentphd Swift let eminem = User(first: "eminem") Kotlin val eminem = User(first = "eminem")
28. @skentphd Swift let eminem = User(first: "eminem") eminem.first // "eminem" Kotlin val eminem = User(first = "eminem") eminem.first // "eminem"
29. @skentphd Swift let eminem = User(first: "eminem") eminem.first // "eminem" eminem.last // nil Kotlin val eminem = User(first = "eminem") eminem.first // "eminem" eminem.last // null
30. @skentphd Swift let eminem = User(first: "eminem") eminem.first // "eminem" eminem.last // nil "\(eminem.first) \(eminem.last)" // "eminem nil" Kotlin val eminem = User(first = "eminem") eminem.first // "eminem" eminem.last // null "${eminem.first} ${eminem.last}" // "eminem null"
31. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
32. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
33. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
34. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
35. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
36. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } stuart.fullName() // "stuart kent" eminem.fullName() // "eminem" class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } stuart.fullName() // "stuart kent" eminem.fullName() // "eminem" Kotlin
37. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } Kotlin
38. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } Kotlin
39. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } Kotlin
40. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } Kotlin
41. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } Kotlin
42. @skentphd Swift extension String { func cap() -> String { guard !isEmpty else { return "" } return String(uppercased().first!) + dropFirst() } } "stuart".cap() // "Stuart" fun String.cap(): String { if (isEmpty()) return "" return toUpperCase().first() + drop(1) } "stuart".cap() // "Stuart" Kotlin
43. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
44. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .joinToString(" ") } } Kotlin
45. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .map { $0!.cap() } .joined(separator: " ") } } class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .map { it.cap() } .joinToString(" ") } } Kotlin
46. @skentphd Swift class User { // ... func fullName() -> String { return [first, last] .flatMap { $0 } .map { $0!.cap() } .joined(separator: " ") } } stuart.fullName() // "Stuart Kent" eminem.fullName() // "Eminem" class User { // ... fun fullName(): String { return arrayOf(first, last) .filterNotNull() .map { it.cap() } .joinToString(" ") } } stuart.fullName() // "Stuart Kent" eminem.fullName() // "Eminem" Kotlin
47. @skentphd Swift class User { // ... var reversedName: String { return fullName() .split(separator: " ") .map { String($0) } .reversed() .joined(separator: ", ") } } class User { // ... val reversedName: String get() = fullName() .split(Regex(" ")) // No explicit cast needed. .asReversed() .joinToString(", ") } Kotlin
48. @skentphd Swift class User { // ... var reversedName: String { return fullName() .split(separator: " ") .map { String($0) } .reversed() .joined(separator: ", ") } } class User { // ... val reversedName: String get() = fullName() .split(Regex(" ")) // No explicit cast needed. .asReversed() .joinToString(", ") } Kotlin
49. @skentphd Swift class User { // ... var reversedName: String { return fullName() .split(separator: " ") .map { String($0) } .reversed() .joined(separator: ", ") } } class User { // ... val reversedName: String get() = fullName() .split(Regex(" ")) // No explicit cast needed. .asReversed() .joinToString(", ") } Kotlin
50. @skentphd Swift class User { // ... var reversedName: String { return fullName() .split(separator: " ") .map { String($0) } .reversed() .joined(separator: ", ") } } stuart.reversedName // "Kent, Stuart" eminem.reversedName // "Eminem" class User { // ... val reversedName: String get() = fullName() .split(Regex(" ")) // No explicit cast needed. .asReversed() .joinToString(", ") } stuart.reversedName // "Kent, Stuart" eminem.reversedName // "Eminem" Kotlin
51. @skentphd Swift enum Type { case visa case masterCard case discover } enum class Type { VISA, MASTERCARD, DISCOVER } Kotlin
52. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } Kotlin
53. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } Kotlin
54. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } Kotlin
55. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } Kotlin
56. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } Kotlin
57. @skentphd Swift enum Type { case visa case masterCard case discover } func getUrl(t: Type) -> String { switch t { case .visa: return "/visa" case .masterCard: return "/mc" case .discover: return "/disc" // No default case required! } } getUrl(t: .discover) // "/disc" enum class Type { VISA, MASTERCARD, DISCOVER } fun getUrl(t: Type): String { return when (t) { VISA -> "/visa" MASTERCARD -> "/mc" DISCOVER -> "/disc" // No default case required! } } getUrl(DISCOVER) // "/disc" Kotlin
58. @skentphd Swift enum Method { case cash case card(String) } sealed class Method { class Cash : Method() class Card(val num: String):Method() } Kotlin
59. @skentphd Swift enum Method { case cash case card(String) } func getUrl(m: Method) -> String { switch method { case .cash: return "/cash" case .card(let num): return "/card/\(num)" // No default case required! } } sealed class Method { class Cash : Method() class Card(val num: String):Method() } fun getUrl(m: Method): String { return when (method) { is Cash -> "/cash" is Card -> "/card/${method.num}" // No default case required! } } Kotlin
60. @skentphd Swift enum Method { case cash case card(String) } func getUrl(m: Method) -> String { switch method { case .cash: return "/cash" case .card(let num): return "/card/\(num)" // No default case required! } } sealed class Method { class Cash : Method() class Card(val num: String):Method() } fun getUrl(m: Method): String { return when (method) { is Cash -> "/cash" is Card -> "/card/${method.num}" // No default case required! } } Kotlin
61. @skentphd Swift enum Method { case cash case card(String) } func getUrl(m: Method) -> String { switch method { case .cash: return "/cash" case .card(let num): return "/card/\(num)" // No default case required! } } sealed class Method { class Cash : Method() class Card(val num: String):Method() } fun getUrl(m: Method): String { return when (method) { is Cash -> "/cash" is Card -> "/card/${method.num}" // No default case required! } } Kotlin
62. @skentphd Swift enum Method { case cash case card(String) } func getUrl(m: Method) -> String { switch method { case .cash: return "/cash" case .card(let num): return "/card/\(num)" // No default case required! } } sealed class Method { class Cash : Method() class Card(val num: String):Method() } fun getUrl(m: Method): String { return when (method) { is Cash -> "/cash" is Card -> "/card/${method.num}" // No default case required! } } Kotlin
63. @skentphd Swift enum Method { case cash case card(String) } func getUrl(m: Method) -> String { switch method { case .cash: return "/cash" case .card(let num): return "/card/\(num)" // No default case required! } } // "/card/1234" getUrl(m: .card("1234")) sealed class Method { class Cash : Method() class Card(val num: String):Method() } fun getUrl(m: Method): String { return when (method) { is Cash -> "/cash" is Card -> "/card/${method.num}" // No default case required! } } // "/card/1234" getUrl(Card("1234")) Kotlin
64. @skentphd So far, soooo good...
65. @skentphd Swift struct Name { let first: String let last: String? } data class Name( val first: String, val last: String? = null) Kotlin
66. @skentphd Swift struct Name { let first: String let last: String? } let stuartName = Name(first: "Stuart", last: "Kent") data class Name( val first: String, val last: String? = null) val stuartName = Name(first="Stuart", last="Kent") Kotlin
67. @skentphd Swift struct Name { let first: String let last: String? } let stuartName = Name(first: "Stuart", last: "Kent") let eminemName = Name(first: "Eminem", last: null) data class Name( val first: String, val last: String? = null) val stuartName = Name(first="Stuart", last="Kent") val eminemName = Name(first="Eminem") Kotlin
68. @skentphd Swift // Value type struct Name { let first: String let last: String? } let stuartName = Name(first: "Stuart", last: "Kent") let eminemName = Name(first: "Eminem", last: null) // Reference type data class Name( val first: String, val last: String? = null) val stuartName = Name(first="Stuart", last="Kent") val eminemName = Name(first="Eminem") Kotlin
69. @skentphd Swift // Value type struct Name { let first: String let last: String? } let stuartName = Name(first: "Stuart", last: "Kent") let eminemName = Name(first: "Eminem", last: null) // Reference type data class Name( val first: String, val last: String? = null) val stuartName = Name(first="Stuart", last="Kent") val eminemName = Name(first="Eminem") val littleStuartName = stuartName.copy(last = "Little") Kotlin
70. @skentphd Swift // Value type struct Name { let first: String let last: String? } let stuartName = Name(first: "Stuart", last: "Kent") let eminemName = Name(first: "Eminem", last: null) // Reference type data class Name( val first: String, val last: String? = null) val stuartName = Name(first="Stuart", last="Kent") val eminemName = Name(first="Eminem") val littleStuartName = stuartName.copy(last = "Little") Kotlin
71. @skentphd Swift protocol InitialsProvider { func initials() -> String } interface InitialsProvider { fun initials(): String } Kotlin
72. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } Kotlin
73. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } Kotlin
74. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } Kotlin
75. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } Kotlin
76. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } Kotlin
77. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User: InitialsProvider { // ... func initials() -> String { return fullName() .split(separator: " ") .map { String($0.first!) } .joined(separator: "") } } stuart.initials() // "SK" eminem.initials() // "E" interface InitialsProvider { fun initials(): String } class User : InitialsProvider { // ... override fun initials(): String { return fullName() .split(Regex(" ")) .map { it.first() } .joinToString("") } } stuart.initials() // "SK" eminem.initials() // "E" Kotlin
78. @skentphd Swift protocol InitialsProvider { func initials() -> String } Kotlin
79. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} Kotlin
80. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} extension User: InitialsProvider { func initials() -> String {/**/} } Kotlin
81. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} extension User: InitialsProvider { func initials() -> String {/**/} } Kotlin
82. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} extension User: InitialsProvider { func initials() -> String {/**/} } Kotlin
83. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} extension User: InitialsProvider { func initials() -> String {/**/} } stuart is InitialsProvider // true Kotlin
84. @skentphd Swift protocol InitialsProvider { func initials() -> String } class User {/**/} extension User: InitialsProvider { func initials() -> String {/**/} } stuart is InitialsProvider // true ⛔ Kotlin
85. @skentphd Swift extension ProgressIndicatable where Self: UIViewController {/**/} Kotlin
86. @skentphd Swift extension ProgressIndicatable where Self: UIViewController {/**/} extension Stack where Element: Equatable {/**/} Kotlin
87. @skentphd Swift extension ProgressIndicatable where Self: UIViewController {/**/} extension Stack where Element: Equatable {/**/} ⛔ Kotlin
88. @skentphd Architecture
89. @skentphd Shared Architectures • ⛔ Protocol-oriented • ✅ Platform-agnostic: MVP, MVVM, etc.
90. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // Mockable interface UserView { // View updating methods } Android
91. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // (Unit) Testable class UserPresenter { weak var view: UserView init(_ view: UserView) {/**/} func start() {} func stop() {} // Other view update callbacks } // Mockable interface UserView { // View updating methods } // (Unit) Testable class UserPresenter { var view: UserView constructor(view: UserView) {/**/} fun start() {} fun stop() {} // Other view update callbacks } Android
92. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // (Unit) Testable class UserPresenter { weak var view: UserView init(_ view: UserView) {/**/} func start() {} func stop() {} // Other view update callbacks } // Mockable interface UserView { // View updating methods } // (Unit) Testable class UserPresenter { var view: UserView constructor(view: UserView) {/**/} fun start() {} fun stop() {} // Other view update callbacks } Android
93. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // (Unit) Testable class UserPresenter { weak var view: UserView init(_ view: UserView) {/**/} func start() {} func stop() {} // Other view update callbacks } // Mockable interface UserView { // View updating methods } // (Unit) Testable class UserPresenter { var view: UserView constructor(view: UserView) {/**/} fun start() {} fun stop() {} // Other view update callbacks } Android
94. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // (Unit) Testable class UserPresenter { weak var view: UserView init(_ view: UserView) {/**/} func start() {} func stop() {} // Other view update callbacks } // Mockable interface UserView { // View updating methods } // (Unit) Testable class UserPresenter { var view: UserView constructor(view: UserView) {/**/} fun start() {} fun stop() {} // Other view update callbacks } Android
95. @skentphd iOS // Mockable protocol UserView: class { // View updating methods } // (Unit) Testable class UserPresenter { weak var view: UserView init(_ view: UserView) {/**/} func start() {} func stop() {} // Other view update callbacks } // Mockable interface UserView { // View updating methods } // (Unit) Testable class UserPresenter { var view: UserView constructor(view: UserView) {/**/} fun start() {} fun stop() {} // Other view update callbacks } Android
96. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
97. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
98. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
99. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
100. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
101. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
102. @skentphd iOS class UserVC: UIViewController, UserView { var userPresenter: UserPresenter? override func viewDidLoad() { super.viewDidLoad() userPresenter = UserPresenter(self) } override func viewWillAppear(/**/) { super.viewWillAppear(/**/) userPresenter?.start() } override func viewWillDisappear(/**/) { userPresenter?.stop() super.viewWillDisappear(/**/) } } class UserActivity: Activity(), UserView { var userPresenter: UserPresenter? = null override fun onCreate(/**/) { super.onCreate(/**/) userPresenter = UserPresenter(this) } override fun onStart() { super.onStart() userPresenter?.start() } override fun onStop() { userPresenter?.stop() super.onStop() } } Android
103. @skentphd Layouts
104. @skentphd 2008 iPhone iOS
105. @skentphd 2008 iPhone 2010 iPad iOS
106. @skentphd 2008 iPhone 2010 iPad 2012 iPhone 5; iPad mini; AutoLayout iOS
107. @skentphd 2008 iPhone 2010 iPad 2012 iPhone 5; iPad mini; AutoLayout 2014 iPhone 6; iPhone 6 Plus iOS
108. @skentphd 2008 iPhone 2010 iPad 2012 iPhone 5; iPad mini; AutoLayout 2014 iPhone 6; iPhone 6 Plus 2015 UIStackView iOS
109. @skentphd 2009 Android 1.0 (internal) Android
110. @skentphd 2009 Android 1.0 (internal) 2009 AbsoluteLayout replaced by LinearLayout, RelativeLayout Android
111. @skentphd 2009 Android 1.0 (internal) 2009 AbsoluteLayout replaced by LinearLayout, RelativeLayout 2009 Android 1.6 (public) Android
112. @skentphd 2009 Android 1.0 (internal) 2009 AbsoluteLayout replaced by LinearLayout, RelativeLayout 2009 Android 1.6 (public) 2017 ConstraintLayout released Android
113. @skentphd iOS vs Android Similarities: • Precise → adaptive • General, performant option • Specialized, maintainable option(s)
114. @skentphd AutoLayout vs ConstraintLayout Similarities: • Powerful • Design via GUI • Based on Cassowary algorithm • Simple slick animations
115. @skentphd AutoLayout vs ConstraintLayout Differences: • Default behaviors • Fallback handling
116. @skentphd UIStackView vs LinearLayout Similarities: • Maintainable • Orientation control • Graceful dynamic behaviors
117. @skentphd UIStackView vs LinearLayout Differences: • Weighting
118. @skentphd Use AutoLayout* or ConstraintLayout when #PerfMatters. Use UIStackView or LinearLayout when #SanityMatters.
119. @skentphd
120. @skentphd
121. @skentphd
122. @skentphd
123. @skentphd Resources & Tactics
124. @skentphd Resources • http://nilhcem.com/swift-is-like-kotlin/
125. @skentphd Resources • http://nilhcem.com/swift-is-like-kotlin/ • https://kotlinlang.org/docs/tutorials/getting-started.html
126. @skentphd Resources • http://nilhcem.com/swift-is-like-kotlin/ • https://kotlinlang.org/docs/tutorials/getting-started.html • https://kotlinlang.org/docs/tutorials/koans.html
127. @skentphd Resources • http://nilhcem.com/swift-is-like-kotlin/ • https://kotlinlang.org/docs/tutorials/getting-started.html • https://kotlinlang.org/docs/tutorials/koans.html • https://kotlinlang.org/docs/tutorials/kotlin-android.html
128. @skentphd Tactics • Ride the wave
129. @skentphd Tactics • Ride the wave • Read Android PRs; ask questions
130. @skentphd Tactics • Ride the wave • Read Android PRs; ask questions • Build a small Android app
131. @skentphd Tactics • Ride the wave • Read Android PRs; ask questions • Build a small Android app • Use IntelliJ's auto-conversion to turn Java/ Android code samples into Kotlin.
132. @skentphd Q&A