Swift School #1

Swift Школа
Сергей Пронин
Empatika

План
• Интро
• Why Swift?
• Как подружить Objective-C и Swift?

Интро
Сергей Пронин 
Ведущий разработчик Empatika
Ведущий разработчик App in the Air
Преподаватель НИУ-ВШЭ
@spronin
sergey@pronin.me

Why Swift?
• Multiple return values
• Optionals -> Safety
• Playgrounds
• Extensions
• Powerful enums
• Sweet syntax

var variable: Double = 55
variable = 12
let constant = 42 //implicit Int
let str = "Answer is (constant)"
var ar: [Int] = [1, 2, 3]
var dic: [String: AnyObject] = ["key": "value",
"num": 123]
for n in ar {
if n % 2 == 0 {
println(n)
}
}
for (key, value) in dic {
println("(key) -> (value)")
}

var optional: String? = "Hello?"
if let exists = optional {
println(exists)
}
if optional != nil {
println(optional!)
}
if optional?.hasSuffix("?") { 
println("somebody home?")
}

let lang = "swift"
switch (lang) {
case "swift":
println("young")
case let x where x.hasSuffix("#"):
println("wat?")
case "js", "css":
println("web")
default:
println("java, is it you?")
}
//add <break> to exit clause
//add <fallthrough> to fall through

for i in 0..<ar.count { //0...n = [0,n]
println(ar[i])
}
for var i = 0; i < ar.count; i++ {
println(ar[i])
}
do {
fetchMessagesFromServer()
sleep(5)
} while true
while ar.count > 0 {
ar.removeLast()
}

func confession(name: String) -> String {
return "I miss (name)"
}
confession("my mom")
func fl(a: [AnyObject]) ->
(first: AnyObject, last: AnyObject) {
return (a[0], a[a.count-1])
}
var result = fl(ar)
println(result.first)
println(result.1)

func params(numbers: Int…) -> Int {
var sum = 0
for n in numbers {
sum += n
}
return sum
}
params(1, 1, 2, 3, 5, 8)

func isEven(n: Int) -> Bool {
return n % 2 == 0
}
func filter(a: [Int], check: Int -> Bool)
-> [Int] {
var result: [Int] = []
for n in a {
if check(n) {
result.append(n)
}
}
return result
}
filter(0...10, isEven)

filter(0...10, { (item: Int) -> Bool in
return item % 2 == 0
})
filter(0...100, { item in item % 10 == 0 })
filter(0...100, { $0 % 10 == 0 })
filter(0...100) { $0 % 10 == 0 }

class Shape {
var sides = 0
var name: String
init(name: String) {
self.name = name
}
func description() -> String {
return "Sides -> (sides)"
}
}
var shape = Shape(name: "ama shape")
shape.description()

class Triangle: Shape {
var a, b, c: Int
init(name: String, sides a: Int, _ b: Int, _ c: Int) {
self.a = a
self.b = b
self.c = c
super.init(name: name)
self.sides = 3
}
var perimeter: Int {
get {
return a + b + c
}
}
override func description() -> String {
return "Triangle with perimeter -> (perimeter)"
}
}
var tr = Triangle(name: "Tr", sides: 5, 10, 20)
tr.description

extension Shape {
class func plusFunction() -> String {
return "I’m a class function "
}
}
Shape.plusFunction()
struct StructShape {
//all the same code, actually
static func plusFunction() -> String {
return "Passed by value"
}
}
//struct objects are being passed by value
//class objects are being passed by reference

enum Status: Int {
case Undetermined, Success, Failure
}
func sendRequest() -> Status {
//networking magic
return Status.Success
}
var result = sendRequest()
switch result {
case .Success:
println("success")
case .Failure:
println("failure")
case .Undetermined:
println("n/a")
}
result = Status.fromRaw(1)! //Success
result.toRaw() //1

protocol NetworkingDelegate {
func request(request: NSURLRequest,
completedWithResult result: NSData?)
}
class ServerHelper {
var delegate: NetworkingDelegate?
func doRequest(request: NSURLRequest) {
var data = NSData(contentsOfURL: request.URL)
delegate?.request(request, completedWithResult: data)
}
}
class Controller: NetworkingDelegate {
func request(request: NSURLRequest,
completedWithResult result: NSData?) {
println("magic")
}
let helper = ServerHelper()
helper.delegate = Controller()
let url = NSURL(string: "http://empatika.com")
helper.doRequest(NSURLRequest(URL: url)))

Готовимся
typedef enum {
StatusSuccess, StatusFailure
} Status
typedef NS_ENUM(NSInteger, Status) {
StatusSuccess, StatusFailure
};

+ (id)sharedInstance {
//your singleton magic
}
+ (instancetype)sharedInstance {
//singleton magic
}
- (instancetype)init {
//initial magic
}

• В существующей Objective-C codebase ->  
New File - Cocoa Touch Class -> Swift -> 
Conﬁgure Header
• В созданный Bridging Header импортируем все,
что Swift должен видеть из Obj-C 
#import “MyAFAPIClient.h”
• Чтобы Obj-C видел из Swift импортируем 
#import “ProductModuleName-Swift.h”
• Открыть Swift-классы и протоколы через @objc 
@objc(Venue) 
class Venue {…}

Перегнать модель или
Controller на Swift
Начать новый проект на
Swift с модели или
Controller-а

Swift School #1

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