Presented at the Swift Delhi Meetup https://swiftindia.github.io/swiftindia/

1. @NatashaTheRobot

2. • @NatashaTheRobot 🤖
• NatashaTheRobot.com
• This Week in Swift Newsletter
• Swift Jobs
• tryswift.co 🐥#🎉
• @NatashaTheNomad %

3. UITableViewDelegate
UITableViewDataSource
UITextFieldDelegate
NSURLSessionDelegate
CLLocationManagerDelegate
MCSessionDelegate

4. Protocol-Oriented Programming in Swift
Dave Abrahams Professor of Blowing-Your-Mind

5. –- Professor of Blowing-Your-Mind
"Swift Is a Protocol-Oriented Programming Language"

7. Practical POP
• View
• (UITable)ViewController
• Networking

8. POP Views

11. // FoodImageView.swift
import UIKit
class FoodImageView: UIImageView {
func shake() {
let animation = CABasicAnimation(keyPath: "position")
animation.duration = 0.05
animation.repeatCount = 5
animation.autoreverses = true
animation.fromValue = NSValue(cgPoint: CGPoint(x: self.center.x - 4.0, y: self.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: self.center.x + 4.0, y: self.center.y))
layer.add(animation, forKey: "position")
}

12. // ViewController.swift
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var foodImageView: FoodImageView!
@IBAction func onShakeButtonTap(sender: AnyObject) {
foodImageView.shake()
}
}

13. 💃💃💃

15. // ShakeableButton.swift
import UIKit
class ActionButton: UIButton {
func shake() {
let animation = CABasicAnimation(keyPath: "position")
animation.duration = 0.05
animation.repeatCount = 5
animation.autoreverses = true
animation.fromValue = NSValue(cgPoint: CGPoint(x: self.center.x - 4.0, y: self.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: self.center.x + 4.0, y: self.center.y))
layer.add(animation, forKey: "position")
}
}

16. // ViewController.swift
class ViewController: UIViewController {
@IBOutlet weak var foodImageView: FoodImageView!
@IBOutlet weak var actionButton: ActionButton!
@IBAction func onShakeButtonTap(sender: AnyObject) {
foodImageView.shake()
actionButton.shake()
}
}

17. 🤔

18. // UIViewExtension.swift
import UIKit
extension UIView {
func shake() {
let animation = CABasicAnimation(keyPath: "position")
animation.duration = 0.05
animation.repeatCount = 5
animation.autoreverses = true
animation.fromValue = NSValue(cgPoint: CGPoint(x: self.center.x - 4.0, y: self.center.y))
animation.toValue = NSValue(cgPoint: CGPoint(x: self.center.x + 4.0, y: self.center.y))
layer.add(animation, forKey: "position")
}
}

19. class FoodImageView: UIImageView {
// other customization here
}
class ActionButton: UIButton {
// other customization here
}
class ViewController: UIViewController {
@IBOutlet weak var foodImageView: FoodImageView!
@IBOutlet weak var actionButton: ActionButton!
@IBAction func onShakeButtonTap(sender: AnyObject) {
foodImageView.shake()
actionButton.shake()
}
}

21. // Shakeable.swift
import UIKit
protocol Shakeable { }
extension Shakeable where Self: UIView {
func shake() {
// implementation code
}
}

22. class FoodImageView: UIImageView, Shakeable {
}
class ActionButton: UIButton, Shakeable {
}

23. class FoodImageView: UIImageView, Shakeable, Dimmable {
}

24. class FoodImageView: UIImageView, Dimmable {
}

25. Transparent View Controllers
and Dim Backgrounds
totem.training

26. 👯👯👯👯👯

27. POP (UITable)ViewControllers

29. // FoodLaLaViewController
override func viewDidLoad() {
super.viewDidLoad()
let foodCellNib = UINib(nibName: "FoodTableViewCell", bundle: nil)
tableView.register(foodCellNib,
forCellReuseIdentifier: "FoodTableViewCell")
}

30. let foodCellNib = UINib(nibName: String(describing: FoodTableViewCell.self),
bundle: nil)
tableView.register(foodCellNib,
forCellReuseIdentifier: String(describing: FoodTableViewCell.self))

31. protocol ReusableView: class {}
extension ReusableView where Self: UIView {
static var reuseIdentifier: String {
return String(describing: self)
}
}

32. extension UITableViewCell: ReusableView { }
FoodTableViewCell.reuseIdentifier
// FoodTableViewCell

33. let foodCellNib = UINib(nibName: "FoodTableViewCell",
bundle: nil)
tableView.register(foodCellNib,
forCellReuseIdentifier: FoodTableViewCell.reuseIdentifier)

34. protocol NibLoadableView: class { }
extension NibLoadableView where Self: UIView {
static var nibName: String {
return String(describing: self)
}
}

35. extension FoodTableViewCell: NibLoadableView { }
FoodTableViewCell.nibName
// "FoodTableViewCell"

36. let foodCellNib = UINib(nibName: FoodTableViewCell.nibName, bundle: nil)
tableView.register(foodCellNib,
forCellReuseIdentifier: FoodTableViewCell.reuseIdentifier)

37. extension UITableView {
func register<T: UITableViewCell>(_: T.Type)
where T: ReusableView, T: NibLoadableView
{
let nib = UINib(nibName: T.nibName, bundle: nil)
register(nib, forCellReuseIdentifier: T.reuseIdentifier)
}
}

38. let foodCellNib = UINib(nibName: "FoodTableViewCell", bundle: nil)
tableView.register(foodCellNib,
forCellReuseIdentifier: "FoodTableViewCell")

39. tableView.register(FoodTableViewCell.self)

40. extension UITableView {
func dequeueReusableCell<T: UITableViewCell>(forIndexPath indexPath: IndexPath) -> T
where T: ReusableView
{
guard let cell = dequeueReusableCell(withIdentifier: T.reuseIdentifier,
for: indexPath as IndexPath) as? T
else {
fatalError("Could not dequeue cell with identifier: (T.reuseIdentifier)")
}
return cell
}
}

41. guard let cell = tableView.dequeueReusableCell(withIdentifier: “FoodTableViewCell", forIndexPath: indexPath)
as? FoodTableViewCell
else {
fatalError("Could not dequeue cell with identifier: FoodTableViewCell")
}

42. let cell = tableView.dequeueReusableCell(forIndexPath: indexPath) as FoodTableViewCell

43. if indexPath.row == 0 {
return tableView.dequeueReusableCell(forIndexPath: indexPath) as DesertTableViewCell
}
return tableView.dequeueReusableCell(forIndexPath: indexPath) as FoodTableViewCell

44. iOS Cell Registration & Reusing with
Swift Protocol Extensions and
Generics
medium.com/@gonzalezreal

45. Protocol-Oriented Segue
Identifiers in Swift
natashatherobot.com

47. POP Networking

48. struct FoodService {
func get(completionHandler: Result<[Food]> -> Void) {
// make asynchronous API call
// and return appropriate result
}
}

49. enum Result<T> {
case Success(T)
case Failure(Error)
}

50. struct FoodService {
func get(completionHandler: (Result<[Food]>) -> Void) {
// make asynchronous API call
// and return appropriate result
}
}

51. // FoodLaLaViewController
var dataSource = [Food]() {
didSet {
tableView.reloadData()
}
}
override func viewDidLoad() {
super.viewDidLoad()
getFood()
}
private func getFood() {
FoodService().get() { [weak self] result in
switch result {
case .Success(let food):
self?.dataSource = food
case .Failure(let error):
self?.showError(error: error)
}
}
}

52. View Controller Tests?!!! 😱

53. // FoodLaLaViewController
var dataSource = [Food]() {
didSet {
tableView.reloadData()
}
}
override func viewDidLoad() {
super.viewDidLoad()
getFood()
}
private func getFood() {
FoodService().get() { [weak self] result in
switch result {
case .Success(let food):
self?.dataSource = food
case .Failure(let error):
self?.showError(error)
}
}
}

54. // FoodLaLaViewController
func getFood(fromService service: FoodService) {
service.getFood() { [weak self] result in
// handle result
}
}

55. // FoodLaLaViewControllerTests
func testFetchFood() {
viewController.getFood(fromService: FoodService())
// 🤔 now what?
}

56. struct FoodService {
func get(completionHandler: (Result<[Food]>) -> Void) {
// make asynchronous API call
// and return appropriate result
}
}

57. protocol Gettable {
associatedtype T
func get(completionHandler: (Result<T>) -> Void)
}

58. struct FoodService: Gettable {
func get(completionHandler: (Result<[Food]>) -> Void) {
// make asynchronous API call
// and return appropriate result
}
}

59. // FoodLaLaViewController
override func viewDidLoad() {
super.viewDidLoad()
getFood(fromService: FoodService())
}
func getFood<S: Gettable>(fromService service: S) where S.T == [Food] {
service.get() { [weak self] result in
switch result {
case .Success(let food):
self?.dataSource = food
case .Failure(let error):
self?.showError(error)
}
}
}

60. // FoodLaLaViewControllerTests
class Fake_FoodService: Gettable {
var getWasCalled = false
func get(completionHandler: (Result<[Food]>) -> Void) {
getWasCalled = true
completionHandler(Result.Success(food))
}
}

61. // FoodLaLaViewControllerTests
func testFetchFood() {
let fakeFoodService = Fake_FoodService()
viewController.getFood(fromService: fakeFoodService)
XCTAssertTrue(fakeFoodService.getWasCalled)
XCTAssertEqual(viewController.dataSource.count, food.count)
XCTAssertEqual(viewController.dataSource, food)
}

62. Update: View Controller Data
Injection with Storyboards and
Segues in Swift
natashatherobot.com

63. Protocols with Associated Types
Alexis Gallagher
2015.funswiftconf.com

64. 😎😎😎

65. Practical POP
• View
• (UITable)ViewController
• Networking

66. Beyond Crusty: Real-World
Protocols
Rob Napier
thedotpost.com

67. Blending Cultures: The Best of
Functional, Protocol-Oriented, and
Object-Oriented Programming
Daniel Steinberg
realm.io

68. T H A N K Y O U !
• @NatashaTheRobot 🤖
• NatashaTheRobot.com
• This Week in Swift Newsletter
• Swift Jobs
• tryswift.co 🐥#🎉
• @NatashaTheNomad %

69. @NatashaTheRobot