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![Swift Kotlin let beefBurger = BeefBurger()
let chickenBurger = ChickenBurger()
let fishBurger = FishBurger()
let burgers = [beefBurger, chickenBurger, fishBurger]
for item in burgers {
if item is BeefBurger {
// downcast
let burger = item as BeefBurger
burger.prepare()
}
} Uses is keyword Uses as keyword Type Checks and Casts](https://image.slidesharecdn.com/c7d493d9-384d-4a2a-895b-566075ca556a-150602211421-lva1-app6891/75/Swift-and-Kotlin-Presentation-37-2048.jpg)
Uploaded byAndrzej Sitek
Swift and Kotlin Presentation
The document compares the programming languages Swift and Kotlin. It provides background on the speakers and an outline of the topics to be discussed, including brief introductions to Swift and Kotlin, common language features between the two, demonstrations of code samples, and conclusions. IDEs like Xcode, Android Studio, and AppCode will also be demonstrated.
Swift and Kotlin Presentation
- 1. Swift and Kotlin PaulMurphy and Andrzej Sitek Tuesday, April 14, 2014
- 2. Speakers • Paul Murphy •Background: Java Server Side, Native Android and iOS Development, Javascript • Developed Apps for: Vodafone, MTN, Discover Digital, Avoca Learning, NPN, TVTextbook • Andrzej Sitek • Background: Front-End JavaScript, Node.js, Mobile Web and Native Android Development • Developed Apps for: MTN, Discover Digital, vRide, Vanstar, Egopolis, Mobile Nokaut.pl
- 3. Introduction • Brief discussionof App development and the motivation for Cross Platform Development • The common language features of Swift and Kotlin • Short code demonstration of Swift and Kotlin and a Short IDE demo of AppCode and Android Studio • Conclusions • Questions
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- 5. Cross Platform AppTools
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- 7. Simplified App Architecture ApplicationApplication Activities Fragments ViewControllers Services
- 8. Simplified App Architecture Modeland Business Service Layers Application Application Activities Fragments ViewControllers Services Model and Business Service Layers
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- 10. Model and BusinessService LayersModel and Business Service Layers
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- 13. What is Swift? •"Objective-C without the C" • Relatively new compiled programming language for iOS and OS X. It was Introduced at Apple's 2014 WWDC • It works well with Cocoa Touch, Foundation Classes and integrates well with existing Objective-C code • Developed by Apple and is very well supported • Built with the LLVM compiler framework and uses Objective-C runtime
- 14. Why Swift? • Employsmodern programming concepts • Simplified syntax comparing to Objective-C • Friendly syntax to Java, Javascript and C# developers • By default no pointers and unsafe accessors • Retains key Objective-C concepts • Can run together with C, C++ and Objective-C in a single program
- 15. What features doesSwift bring? • It is a nice syntax which is easy to learn • Strongly typed • Functions are first-class objects • Header files are not required anymore • Error handling rather than exception handling • Full support of Unicode in Strings
- 16. The drawbacks ofSwift • Relatively new - not many apps are written 100% in Swift yet • The iOS APIs are written with legacy data types, e.g. NSArray, NSDictionary - there is poor compatibility between these and the in built Swift datatypes • Swift is a strongly typed language which requires strict control over the initialisation of variables and the use of nil. This is a small challenge to get used to for existing Objective-C, Javascript and Java developers. • Experienced Objective-C developers are reluctant to take Swift on board for major projects. • A knowledge of Objective-C is still necessary when dealing with existing iOS APIs and third party libraries.
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- 19. What is Kotlin? •“Statically typed programming language targeting the JVM and JavaScript” • 100% interoperable with Java • Made by JetBrains (folks behind IntelliJ IDEA and, by extension, Android Studio) • Named after an island near Saint Petersburg (the location of the development office behind the project) • Introduced in 2011 (well before Swift!!!) • Android support came in 2nd milestone release (M2)
- 20. Why Kotlin? • Activelydeveloped and maintained by JetBrains • Designed to be light by excluding all the domain- specific heft • It has some of the core features missing in Java • Easy to integrate with Eclipse, IntelliJ, Android Studio (official JetBrains Kotlin plugin is available) • Versatile, No performance impact, very small runtime • Similar syntax to Swift
- 22. What features doesKotlin bring? • Named and optional arguments • Lambdas • Null and type safety • Data objects • Simple singletons (object notation) • Traits (interfaces with default implementation) • Extension functions
- 23. The drawbacks ofKotlin • It will take time until best practices emerge for Kotlin in the Android world • Annotation processors are not supported (such as Butterknife) • For more effective size and method count you have to enable ProGuard: Original ProGuard Java 55 KB 54 KB Kotlin 396 KB 57 KB Original ProGuard Java 24 11 Kotlin 6,063 53
- 25. Similar Language Features •Variables and Constants • Functions and Methods • Classes and Instantiation • Classes and Inheritance • Protocols and Traits • Enums
- 26. Similar Language Features •Nil and Null Safety (optional variables) • Any and AnyObject • Type Checks and Casts • Generics • Extensions and Typealias • Error Handling
- 27. Swift Kotlin var name:String = "Paul Murphy" var address: String = "Cork" let MON: String = "Monday" let TUE: String = "Tuesday" let WED: String = "Wednesday" let THU: String = "Thursday" let FRI: String = "Friday" var name: String = "Andrzej Sitek" var address: String = "Cork" val MON: String = "Monday" val TUE: String = "Tuesday" val WED: String = "Wednesday" val THU: String = "Thursday" val FRI: String = "Friday" Variables and Constants
- 28. Swift Kotlin class FastFood{ func createBurger(item: String, id: Int) -> Burger { let ingredientFactory = KCIngredientFactory() var burger = BeefBurger(factory: ingredientFactory) return burger } func createPizza(item: String, _ id: Int) -> Burger { let ingredientFactory = KCIngredientFactory() var burger = BeefBurger(factory: ingredientFactory) return burger } fun createOrders() { var burger = createBurger("beef", id: 101) var pizza = createPizza("pepperoni", 101) } } class FastFood { fun createBurger(item: String, id: Int): Burger { val ingredientFactory = KCIngredientFactory() var burger = BeefBurger(factory = ingredientFactory) return burger } fun createPizza(item: String, id: Int): Burger { val ingredientFactory = KCIngredientFactory() var burger = BeefBurger(factory = ingredientFactory) return burger } fun createOrders() { var burger = createBurger("beef", id = 101) var pizza = createPizza("pepperoni", 101) } } Functions and Methods
- 29. Swift Kotlin class Burger{ var id: Int var name: String init(id: Int, name: String) { self.id = id self.name = name } } var burger = Burger(id: 101, name:"KC Burger") class Burger { var id: Int var name: String constructor(id: Int, name: String) { this.id = id this.name = name } } var burger = Burger(id=101, name="KC Burger") Classes and Instantiation
- 30. Swift Kotlin class Burger{ var id: Int var name: String init(id: Int, name: String) { self.id = id self.name = name } } class BeefBurger : Burger { override init(id: Int, name: String) { super.init(id: id, name: name) } } var burger = BeefBurger(id: 101, name:"KC Burger") open class Burger { var id: Int var name: String constructor(id: Int, name: String) { this.id = id this.name = name } } class BeefBurger: Burger { constructor(id: Int, name: String): super(id, name) { } } var burger = BeefBurger(id=101, name="KC Burger") Classes and Inheritance
- 31. Swift Kotlin protocol IngredientFactory{ func createBeef() -> Beef func createChicken() -> Chicken func createFish() -> Fish func createCheese() -> Cheese func createToppings() -> Array<Topping> func createSauces() -> Array<Sauce> } trait IngredientFactory { fun createBeef(): Beef fun createChicken(): Chicken fun createFish(): Fish fun createCheese(): Cheese fun createToppings(): ArrayList<Topping> fun createSauces(): ArrayList<Sauce> } Protocols and Traits
- 32. Swift Kotlin class KCIngredientFactory:IngredientFactory { func createBeef() -> Beef { return CorkBeef() } func createChicken() -> Chicken { return ChickenBreast() } func createFish() -> Fish { return BatteredFish() } func createCheese() -> Cheese { return Cheese.MatureCheddar } func createToppings() -> Array<Topping> { var toppings = Array<Topping>() toppings.add(Topping.Onions) return toppings } func createSauces() -> Array<Sauce> { var sauces = Array<Sauce>() sauces.add(Sauce.Mayo) sauces.add(Sauce.Ketchup) return sauces } class KCIngredientFactory: IngredientFactory { override fun createBeef(): Beef { return CorkBeef() } override fun createChicken(): Chicken { return ChickenBreast() } override fun createFish(): Fish { return BatteredFish() } override fun createCheese(): Cheese { return Cheese.MatureCheddar } override fun createToppings(): ArrayList<Topping> { var toppings = ArrayList<Topping>() toppings.add(Topping.Onions) return toppings } fun createSauces(): Array<Sauce> { var sauces = ArrayList<Sauce>() sauces.add(Sauce.Mayo) sauces.add(Sauce.Ketchup) return sauces } Protocols and Traits
- 33. Swift Kotlin enum Cheese{ case MatureCheddar case MeltyCheese } enum Topping { case IcebergLettuce case Gherkins case Pickles case Onions } enum Sauce { case Mayo case Ketchup case Mustard } enum class Cheese { MatureCheddar MeltyCheese } enum class Topping { IcebergLettuce Gherkins Pickles Onions } enum class Sauce { Mayo Ketchup Mustard } Enums
- 34. The Billion DollarMistake Tony Hoare I call it my billion-dollar mistake. It was the invention of the null reference in 1965…..But I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years.
- 35. Swift Kotlin var a:String = “abc” a = nil // compilation error var b: String? = “abc” b = nil // ok class KCBurgerStand: BurgerStand { let factory = KCIngredientFactory() func createBurger(item: String) -> Burger { var burger: Burger? if (item == "beef") { burger = BeefBurger(factory: factory) burger!.name = "KC Special Burger" } else if (item == "chicken") { burger = ChickenBurger(factory: factory) burger!.name = "KC Breast In A Bun" } else if (item == "fish") { burger = FishBurger(factory: factory) burger!.name = "KC Atlantis Fish Burger" } return burger! } } var a: String = “abc” a = null // compilation error var b: String? = “abc” b = null // ok class KCBurgerStand: BurgerStand { val factory = KCIngredientFactory() fun createBurger(item: String): Burger { var burger: Burger? = null if (item == "beef") { burger = BeefBurger(factory: factory) burger!!.name = "KC Special Burger" } else if (item == "chicken") { burger = ChickenBurger(factory: factory) burger!!.name = "KC Creole In A Bun" } else if (item == "fish") { burger = FishBurger(factory: factory) burger!!.name = "KC Atlantis Fish Burger" } return burger!! } } Nil and Null Safety
- 36. Swift Kotlin var anything: Any var object : AnyObject var anything : Any var listOfObjects: List<AnyObject> var listOfAnything: List<Any> Important for interacting with existing Objective-C APIs Objective-C id maps to Swift AnyObject id -> AnyObject var object : Any var listOfObjects: ArrayList<Any> Any and AnyObject
- 37. Swift Kotlin let beefBurger= BeefBurger() let chickenBurger = ChickenBurger() let fishBurger = FishBurger() let burgers = [beefBurger, chickenBurger, fishBurger] for item in burgers { if item is BeefBurger { // downcast let burger = item as BeefBurger burger.prepare() } } Uses is keyword Uses as keyword Type Checks and Casts
- 38. Swift Kotlin func genericFunction<T>(item:T) -> T { } Note: AnyObject V Generics • Strongly Typed • Flexible fun genericFunction<T>(item: T): T { } Generics
- 39. Swift Kotlin extension String{ func toString() -> String { return "summary" } } extension Array { mutating func add(item:T) { append(item) } } typealias Integer = Int typealias HashMap = NSMutableDictionary typealias ArrayList = NSMutableArray fun String.description(): String { return "summary" } Extensions and Typealias
- 40. Swift enum ServerResponse { caseResult(String, String) case Error(String) } let success = ServerResponse.Result("CheeseBurger", "Paul Murphy") let failure = ServerResponse.Error("Out of cheese.") switch success { case let .Result(item, customerName): let serverResponse = "Sunrise is at (item) for (customerName)." case let .Error(error): let serverResponse = "Failure... (error)" } Error Handling
- 41. Ignored Language Features FeatureSwift Kotlin Class Import NO YES Packages NO OPTIONAL Exceptions NO YES Visibility Modifiers YES YES Primary Constructors NO YES Annotations NO YES Tuples YES NO Property Observers YES NO Operator Overloading YES YES Data Classes NO YES Type Safe Builders NO YES Returns and Jumps NO YES
- 42. Language Cheatsheet Swift Kotlin nilnull self this protocol trait init constructor func fun -> : let val AnyObject Any ! !!
- 43. Example Model andService Classes
- 44. Summary • Cross PlatformTools add a layer of complexity and dependency on third parties that can be easily avoided • Native App development on iOS and Android has traditionally been different • Swift and Kotlin share enough similarities in language design and syntax to consider being used in parallel for model and business app layers • The use of a shared and similar IDE platform eases parallel development in both languages
- 45. References • Swift: https://developer.apple.com/swift/ •Kotlin: http://kotlinlang.org • Kotlin web demos: http://kotlin-demo.jetbrains.com/ • Kotlin on Twitter: https://twitter.com/project_kotlin
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