Slajdovi sa iOS Talks 1 u Osijeku, 26.02.2016. Swift 101 - value tipovi, funkcionalno programiranje, zasto Swift > Objective C. http://softwarecity.hr/event/ios-talks-1-swift-u-praksi/

1. SWIFT
U PRAKSI

2. ZAŠTO SWIFT?

3. SWIFT 101

4. LET VS VAR
var myText = "Hello"
myText = "Dobar dan"
let otherText = "Hello"
otherText = "Dobar dan"

5. ?!
var helloString: String? //Optional<String>
print(helloString) //"nil"
helloString = "Hello!"
print(helloString) //"Optional("Hello!")"
print(helloString!) //“Hello!"
helloString = nil
print(helloString!) //CRASH!

6. OPTIONAL CHAINING
?. = CALL ME MAYBE
var user: User?
user?.removeUser()

7. TUPLE
let userData = (name: "Marin", age: 19)
print(userData.name) //"Marin"
print(userData.0) //"Marin"

8. PATTERN MATCHING
let userData = (name: "Marin", age: 19)
switch userData {
case (_, 0...20):
print("User je mlađi od 20 godina!")
default: break
}

9. PROTOCOL EXTENSIONS
protocol Human {
var name: String { get set }
func sayHello()
}
extension Human {
func sayHello() {
print("Hello, I'm (name)")
}
}
struct Sam: Human {
var name = "Sam"
}

10. PROTOCOL ORIENTED
PROGRAMMING
KOMPONIRANJE > NASLJEĐIVANJE

11. VRIJEDNOST
VRIJEDNOSTI

12. $ grep -e "^struct " stdlib.swift | wc -l
78
$ grep -e "^enum " stdlib.swift | wc -l
8
$ grep -e "^class " stdlib.swift | wc -l
1

13. KAKO?
Class Struct
init ☑ ☑
properties ☑ ☑
methods ☑ ☑
inheritance ☑ 🤔
value tip ❌ ☑
reference tip ☑ ❌

14. VALUE TIP?
var a = [1, 2, 3]
var b = a
// a = [1, 2, 3]; b = [1, 2, 3]
b.append(4)
// a = [1, 2, 3]; b = [1, 2, 3, 4]
var a = UIView()
var b = a
// a.alpha = 1; b.alpha = 1
b.alpha = 0
// a.alpha = 0; b.alpha = 0

15. ŠTO FALI OBJEKTIMA?CONCURRENCY PROBLEMI
SKRIVENI DEPENDECY
NISU IZOLIRANI

16. VALUE?KOPIRAN
IZORLIRAN
ZAMJENJIV

17. VALUE = PODATAK

18. VALUE = STANJE

19. VRIJEDNOSTI RADEOBJEKTI KOORDINIRAJU

20. BTW, ENUM

21. PRIMJER
MVC CHAT APLIKACIJA

22. MODEL

23. struct Message {
let text: String
let username: String
init(username: String, text: String) {
self.username = username
self.text = text
}
}
struct Join {
let username: String
init(username: String, date: NSDate) {
self.username = username
}
}

24. enum ChatEvent {
case Message(username: String, message: String)
case Join(username: String)
}

25. public enum Optional<Wrapped> {
case None
case Some(Wrapped)
}

26. enum ChatEvent {
case Message(username: String, message: String)
case Join(username: String)
}
func displayTextForEvent(event: ChatEvent)-> String {
switch event {
case .Join(let username):
return "(username) joined the chat"
case .Message(let username, let message):
return "(username) said (message)"
}
}

27. enum ChatEvent {
case Message(username: String, message: String)
case Join(username: String)
var textToDisplay: String {
switch self {
case .Join(let username):
return "(username) joined the chat"
case .Message(let username, let message):
return "(username) said (message)"
}
}
}

28. VIEWCONTROLLEROBJEKTI KOORDINIRAJU

29. class ViewController: UIViewController {
var events = [ChatEvent]()
}

30. class ViewController: UIViewController,
UITableViewDelegate {
var events = [ChatEvent]()
let tableView = UITableView()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
}
}

31. extension ViewController: UITableViewDataSource {
enum ChatCellIdentifier: String {
case Message = "messageCell"
case Join = “joinCell"
}
}

32. extension ViewController: UITableViewDataSource {
enum ChatCellIdentifier: String {
case Message = "messageCell"
case Join = "joinCell"
init(event: ChatEvent) {
switch event {
case .Join(username: _):
self = .Join
case .Message(username: _, message: _):
self = .Message
}
}
}

33. extension ViewController: UITableViewDataSource {
//... (enum ChatCellIdentifier)
func numberOfSectionsInTableView(tableView:
UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView,
numberOfRowsInSection section: Int) -> Int {
return events.count
}
}

34. extension ViewController: UITableViewDataSource {
//... (enum ChatCellIdentifier)
//... (section and cell number)
func tableView(tableView: UITableView, cellForRowAtIndexPath
indexPath: NSIndexPath) -> UITableViewCell
{
let event = events[indexPath.row]
let identifier = ChatCellIdentifier(event: event).rawValue
let cell = tableView.dequeueReusa…withIdentifier(identifier)
cell?.textLabel?.text = event.textToDisplay
return cell!
}
}

35. FUNKCIONALNO
PROGRAMIRNAJE

36. PURE FUNCTIONS
A -> B

37. NUSPOJAVENEDEKLARIRANI PARAMETRI I RETURN

38. FUNKCIONALNO =
BEZ STANJA
var text = "Hello"
func addExclamationMarkToText() {
text += "!"
}
func textWithExclamationMark(text: String) -> String {
return text + "!"
}
var text = textWithExclamationMark("Hello")

39. INPUT -> FUNC -> FUNC -> FUNC -> OUTPUT
BOLJI KOD

40. FIRST CLASS CITIZENCLOSURE
var transformStringFunction: (String)->String = { string in
return string + "!"
}
transformStringFunction("Hey") //Hey!
transformStringFunction = { string in
return string + "?"
}
transformStringFunction("Kako si") //Kako si?

41. FUNKCIJE VIŠEG REDAF(G(X))
func transformString(string: String, function: (String)->String) -> String {
return function(string)
}
transformString(“Hello”, function: { string in
return string + "!"
})

42. FILTER

43. OBJC U SWIFTU
func filterNamesWithA(names: [String])-> [String] {
var tempArray = [String]()
for name in names {
if name.containsString("a") {
tempArray.append(name)
}
}
return tempArray
}
let names = ["Josip", "Mladen", "Luka", "Dominik"]
let filteredNames = filterNamesWithA(names)

44. FUNKCIONALNOARRAY.FILTER( (ELEMENT)-> BOOL) )
let names = ["Josip", "Mladen", "Luka", "Dominik"]
let namesWithA = names.filter { name -> Bool in
return name.containsString("a")
}
print(namesWithA) //["Mladen", "Luka"]

45. ŠTO, NE KAKO

46. MAPARRAY.MAP( (ELEMENT)->ELEMENT) )
let lowercaseNames = names.map { name -> String in
return name.lowercaseString
}
print(lowercaseNames) //["mladen", "luka" ...]

47. let users = [
("Marin", 19),
("Filip", 18),
("Luka", 28),
("Josip", 29)
]
let namesOfUnderTwenties = users
.filter { (_, age) -> Bool in
return age < 20
}
.map { (name, _) -> String in
return name
}
print(namesOfUnderTwenties) //["Marin", "Filip"]

48. OOP JE SUPER,
ALI…