面向协议编程与 Cocoa 的邂逅

My talk in MDCC 16. About using Protocol-Oriented Programming language in daily Cocoa life.

Transcript

1. ᶎݻܐᦓᖫᑕӨ Cocoa ጱᮁᭊ
   MDCC 16
   ሴ૛ - 2016 ଙ 9 ์ 24 ෭
   

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2. Ԇ᷌
   • ᩸ɾॳᦩ
   • ಥɾ૬஌
   • ᫨ɾᅾ௡
   • ݳɾജ൐
   

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3. Ԇ᷌
   • ᩸ɾॳᦩ - Ջԍฎ Swi' ܐᦓ
   • ಥɾ૬஌
   • ᫨ɾᅾ௡
   • ݳɾജ൐
   

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4. Ԇ᷌
   • ᩸ɾॳᦩ - Ջԍฎ Swi' ܐᦓ
   • ಥɾ૬஌ - ܐᦓಘ઀޾ᶎݻܐᦓᖫᑕ
   • ᫨ɾᅾ௡
   • ݳɾജ൐
   

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5. Ԇ᷌
   • ᩸ɾॳᦩ - Ջԍฎ Swi' ܐᦓ
   • ಥɾ૬஌ - ܐᦓಘ઀޾ᶎݻܐᦓᖫᑕ
   • ᫨ɾᅾ௡ - ࣁ෭ଉ୏ݎӾֵአܐᦓ
   • ݳɾജ൐
   

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6. Ԇ᷌
   • ᩸ɾॳᦩ - Ջԍฎ Swi' ܐᦓ
   • ಥɾ૬஌ - ܐᦓಘ઀޾ᶎݻܐᦓᖫᑕ
   • ᫨ɾᅾ௡ - ࣁ෭ଉ୏ݎӾֵአܐᦓ
   • Model (Networking)
   • ViewController
   • ݳɾജ൐
   

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7. ᩸ɾॳᦩ
   Ջԍฎ Swi% ܐᦓ
   Protocol
   

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8. protocol Greetable {
   var name: String { get }
   func greet()
   }
   

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9. ᶎݻ੒᨝
   Object-oriented
   

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10. ᶎݻ੒᨝
    class Animal {
    var leg: Int { return 2 }
    func eat() {
    print("eat food.")
    }
    func run() {
    print("run with \(leg) legs")
    }
    }
    class Tiger: Animal {
    override var leg: Int { return 4 }
    override func eat() {
    print("eat meat.")
    }
    }
    let tiger = Tiger()
    tiger.eat() // "eat meat"
    tiger.run() // "run with 4 legs"
    

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11. ViewController → UIViewController
    class ViewCotroller:
    UIViewController
    {
    // ᖀಥ
    // view, isFirstResponder()...
    // ෛے
    func myMethod() {
    }
    }
    

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12. AnotherViewController → UITableViewController → UIViewController
    class AnotherViewController:
    UITableViewController
    {
    // ᖀಥ
    // tableView, isFirstResponder()...
    // ෛے
    func myMethod() {
    }
    }
    

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13. ࢯहԏӞ
    Cross-Cu'ng Concerns
    ཞڔىဳᅩ
    

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14. ᥴ٬ොໜ
    • Copy & Paste
    • ୚ف BaseViewController
    • ׁᩢဳف
    • ग़ᖀಥ
    

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15. Objec&ve-C
    Message Sending
    

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16. ViewController *v1 = ...
    [v1 myMethod];
    AnotherViewController *v2 = ...
    [v2 myMethod];
    

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17. NSArray *array = @[v1, v2];
    for (id obj in array) {
    [obj myMethod];
    }
    

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18. NSObject *v3 = [NSObject new]
    // v3 ဌํਫሿ `myMethod`
    NSArray *array = @[v1, v2, v3];
    for (id obj in array) {
    [obj myMethod];
    }
    // Runtime error:
    // unrecognized selector sent to instance blabla
    

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19. ࢯहԏԫ
    Dynamic Dispatch Safety
    ۖாၝݎਞق௔
    

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20. OOP ࢯह
    • ۖாၝݎਞق௔
    • ཞڔىဳᅩ
    

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21. ܐᦓ
    Protocol
    

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22. Java, C#
    Interface
    

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23. Swift
    protocol
    

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24. Swi$ protocol
    protocol Greetable {
    var name: String { get }
    func greet()
    }
    

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25. Swi$ protocol
    protocol Greetable {
    var name: String { get }
    func greet()
    }
    struct Person: Greetable {
    let name: String
    func greet() {
    print("֦অ \(name)")
    }
    }
    Person(name: "Wei Wang").greet()
    

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26. ಥɾ૬஌
    ܐᦓಘ઀޾ᶎݻܐᦓᖫᑕ
    

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27. OOP ࢯह
    • ۖாၝݎਞق௔
    • ཞڔىဳᅩ
    

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28. protocol Greetable {
    var name: String { get }
    func greet()
    }
    struct Person: Greetable {
    let name: String
    func greet() {
    print("֦অ \(name)")
    }
    }
    

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29. protocol Greetable {
    var name: String { get }
    func greet()
    }
    struct Cat: Greetable {
    let name: String
    func greet() {
    print("meow~ \(name)")
    }
    }
    

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30. let array: [Greetable] = [
    Person(name: "Wei Wang"),
    Cat(name: "onevcat")]
    for obj in array {
    obj.greet()
    }
    // ֦অ Wei Wang
    // meow~ onevcat
    

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31. struct Bug: Greetable {
    let name: String
    }
    // Compiler Error:
    // 'Bug' does not conform to protocol 'Greetable'
    // protocol requires function 'greet()'
    

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32. OOP ࢯह
    • ✅ ۖாၝݎਞق௔
    • ཞڔىဳᅩ
    

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33. ֵአܐᦓوՁդᎱ
    protocol P {
    func myMethod()
    }
    

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34. // class ViewController: UIViewController
    extension ViewController: P {
    func myMethod() {
    doWork()
    }
    }
    // class AnotherViewController: UITableViewController
    extension AnotherViewController: P {
    func myMethod() {
    doWork()
    }
    }
    

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35. Swi$ 2 - ܐᦓಘ઀
    

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36. protocol P {
    func myMethod()
    }
    extension P {
    func myMethod() {
    doWork()
    }
    }
    ԅ P ਧԎጱොဩ൉׀ἕᦊਫሿ
    

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37. extension ViewController: P { }
    extension AnotherViewController: P { }
    viewController.myMethod()
    anotherViewController.myMethod()
    

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38. ਫሿ๚ࣁܐᦓӾ्กጱٖ਻
    protocol P {
    func myMethod()
    }
    extension P {
    func myMethod() {
    doWork()
    }
    func anotherMethod() {
    myMethod()
    someOtherWork()
    }
    }
    viewController.anotherMethod()
    

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39. • ܐᦓਧԎ
    • ൉׀ਫሿጱفݗ
    • ᭽஗ܐᦓጱᔄࣳᵱᥝ੒ٌᬰᤈਫሿ
    • ܐᦓಘ઀
    • ԅفݗ൉׀ἕᦊਫሿ
    • ໑ഝفݗ൉׀᷐क़ਫሿ
    

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40. OOP ࢯह
    • ✅ ۖாၝݎਞق௔
    • ✅ ཞڔىဳᅩ
    

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41. ᫨ɾᅾ௡
    ࣁ෭ଉ୏ݎӾֵአܐᦓ
    

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42. WWDC 15 #408
    Protocol-Oriented Programming in Swi3
    

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43. Model (Networking)
    

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44. ໜֺ
    चԭ Protocol ጱᗑᕶ᧗࿢
    

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45. Demo
    • चԭܐᦓ
    • ᔄࣳਞق
    • ᥴᘠݳ
    • ݢܔᇿၥᦶ
    • ಘ઀௔
    

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46. • Networking:
    • AFNetworking
    • Alamofire
    • (ASIHTTPRequest) !
    • Model Parser
    • SwiAyJSON
    • Argo
    • Himotoki
    

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47. սضᘍᡤֵአܐᦓ
    ṛଶܐᦓ۸ํۗԭᥴᘠ҅ၥᦶզ݊ಘ઀
    

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48. APIKit1 + Himotoki2
    2 h$ps:/
    /github.com/ikesyo/Himotoki
    1 h$ps:/
    /github.com/ishkawa/APIKit
    

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49. Controller
    

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50. ໜֺ
    ړᶭے᫹
    

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51. ړᶭے᫹ጱᗑᕶ᧗࿢
    struct Pagination {
    let items: [T]
    let hasNext: Bool
    }
    struct ChannelsResquest: Request {
    typealias Response = Pagination
    let lastId: Int?
    }
    

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52. class ChannelsTableViewController: UITableViewController {
    private var lastId: Int? = nil
    private var hasNext = true
    override func viewDidLoad() {
    super.viewDidLoad()
    load()
    }
    func load() {
    if hasNext {
    client.send(ChannelsResquest(lastId: lastId)) {
    result in
    }
    }
    }
    }
    

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53. class ChannelsTableViewController: UITableViewController {
    private var lastId: Int? = nil
    private var hasNext = true
    private var data: [Channel] = []
    override func viewDidLoad() {
    super.viewDidLoad()
    load()
    }
    func load() {
    if hasNext {
    client.send(ChannelsResquest(lastId: lastId)) {
    result in
    self.lastId = result!.items.last?.id
    self.hasNext = result!.hasNext
    self.data = result.items
    self.tableView.reloadData()
    }
    }
    }
    }
    

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54. extension ChannelsTableViewController: UITableViewDelegate {
    override func tableView(tableView: UITableView,
    willDisplayCell cell: UITableViewCell,
    forRowAtIndexPath indexPath: NSIndexPath)
    {
    if indexPath.row == data.count - 1 {
    load()
    }
    }
    

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55. ඳԪᬮဌํᕮ๳...
    

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56. ඳԪᬮဌํᕮ๳...
    private var isLoading = false
    func load() {
    if isLoading { return }
    if hasNext {
    isLoading = true
    client.send(ChannelsResquest(lastId: lastId)) {
    result in
    //...
    self.isLoading = false
    }
    }
    }
    

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57. ChannelsTableViewController
    Pagina&on
    

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58. FriendsTableViewController
    Pagina&on
    

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59. ොໜӞғ॔ګᔌᩂ
    

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60. ොໜӞғ॔ګᔌᩂ
    

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61. ොໜԫғᆿᔄ
    

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62. BaseTableViewController
    

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63. class BaseTableViewController: UITableViewController {
    var lastId: Int? = nil
    var hasNext = true
    var isLoading = false
    func loadNext() {
    if isLoading { return }
    if hasNext {
    isLoading = true
    doLoad {result in
    self.lastId = //...
    self.hasNext = //...
    }
    }
    }
    func doLoad(handler: (Any?)->Void) {
    // ??
    }
    }
    

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64. class BaseTableViewController: UITableViewController {
    var lastId: Int? = nil
    var hasNext = true
    var isLoading = false
    func loadNext() {
    if isLoading { return }
    if hasNext {
    isLoading = true
    doLoad {result in
    self.lastId = //...
    self.hasNext = //...
    }
    }
    }
    func doLoad(handler: (Any?)->Void) {
    fatalError("You should implement it in subclass!")
    }
    }
    

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65. class FriendsTableViewController: BaseTableViewController {
    private var data: [Friend] = []
    override func viewDidLoad() {
    super.viewDidLoad()
    loadNext()
    }
    override func doLoad(handler: (Any?)->Void) {
    client.send(FriendsRequest(lastId: lastId)) {
    result in
    handler(result)
    // ...
    self.data = result!.items
    self.tableView.reloadData()
    }
    }
    }
    

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66. View Slide

67. View Slide

68. WTF?
    

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69. • FriendsTableViewController →
    FriendsCollec5onViewController
    

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70. • FriendsTableViewController →
    FriendsCollec5onViewController
    • BaseTableViewController →
    BaseCollec5onViewController
    

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71. • FriendsTableViewController →
    FriendsCollec5onViewController
    • BaseTableViewController →
    BaseCollec5onViewController
    ॔ګᔌᩂ?
    

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72. • FriendsTableViewController →
    FriendsCollec5onViewController
    • BaseTableViewController →
    BaseCollec5onViewController
    ॔ګᔌᩂ
    

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73. ොໜӣғܐᦓ
    

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74. struct NextPageState {
    private(set) var hasNext: Bool
    private(set) var isLoading: Bool
    private(set) var lastId: T?
    init() {
    hasNext = true
    isLoading = false
    lastId = nil
    }
    mutating func reset() {
    hasNext = true
    isLoading = false
    lastId = nil
    }
    mutating func update(hasNext: Bool, isLoading: Bool, lastId: T?) {
    self.hasNext = hasNext
    self.isLoading = isLoading
    self.lastId = lastId
    }
    }
    

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75. protocol NextPageLoadable: class {
    associatedtype DataType
    associatedtype LastIdType
    var data: [DataType] { get set }
    var nextPageState: NextPageState { get set }
    func performLoad(
    successHandler: (_ rows: [DataType],
    _ hasNext: Bool,
    _ lastId: LastIdType?) -> (),
    failHandler: () -> ()
    )
    }
    

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76. protocol NextPageLoadable: class {
    associatedtype DataType
    associatedtype LastIdType
    var data: [DataType] { get set }
    var nextPageState: NextPageState { get set }
    func performLoad(
    successHandler: (_ rows: [DataType],
    _ hasNext: Bool,
    _ lastId: LastIdType?) -> (),
    failHandler: () -> ()
    )
    }
    extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    guard nextPageState.hasNext else { return }
    if nextPageState.isLoading { return }
    

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77. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    guard nextPageState.hasNext else { return }
    if nextPageState.isLoading { return }
    nextPageState.isLoading = true
    performLoad(successHandler: { rows, hasNext, lastId in
    self.data += rows
    self.nextPageState.update(hasNext: hasNext,
    isLoading: false,
    lastId: lastId)
    

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78. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    guard nextPageState.hasNext else { return }
    if nextPageState.isLoading { return }
    nextPageState.isLoading = true
    performLoad(successHandler: { rows, hasNext, lastId in
    self.data += rows
    self.nextPageState.update(hasNext: hasNext,
    isLoading: false,
    lastId: lastId)
    self.tableView.reloadData()
    }, failHandler: {
    //..
    })
    }
    }
    

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79. class FriendTableViewController: UITableViewController {
    var nextPageState = NextPageState()
    var data: [Friend] = []
    }
    extension FriendTableViewController: NextPageLoadable {
    func performLoad(
    successHandler: ([String], Bool, Int?) -> (),
    failHandler: () -> ())
    {
    client.send(FriendsRequest()) {
    result in
    if let result = result {
    successHandler(result.items,
    result.hasNext,
    result.items.last.id)
    } else {
    failHandler()
    }
    }
    }
    }
    

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80. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() { ... }
    }
    

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81. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() { ... }
    }
    extension FriendTableViewController: NextPageLoadable { ... }
    class FriendTableViewController: UITableViewController {
    //...
    override func viewDidLoad() {
    super.viewDidLoad()
    loadNext()
    }
    override func tableView(tableView: UITableView,
    willDisplayCell cell: UITableViewCell,
    forRowAtIndexPath indexPath: NSIndexPath)
    {
    if indexPath.row == data.count - 1 {
    loadNext()
    }
    }
    }
    

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82. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() { ... }
    }
    UICollec(onView ெԍېҘ
    

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83. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() { ... }
    }
    UICollec(onView ெԍېҘ
    ॔ګᔌᩂҘ
    extension NextPageLoadable where Self: UICollectionViewController {
    func loadNext() { ... }
    }
    

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84. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    guard nextPageState.hasNext else { return }
    if nextPageState.isLoading { return }
    nextPageState.isLoading = true
    performLoad(successHandler: { rows, hasNext, lastId in
    self.data += rows
    self.nextPageState.update(hasNext: hasNext, isLoading: false, lastId: lastId)
    self.tableView.reloadData()
    }, failHandler: {
    // Failed when first loading
    if self.nextPageState.lastId == nil {
    self.data = []
    self.nextPageState.reset()
    }
    })
    }
    }
    

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85. tableView.reloadData()
    colletionView.reloadData()
    

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86. tableView.reloadData()
    colletionView.reloadData()
    protocol ReloadableType {
    func reloadData()
    }
    extension UITableView: ReloadableType {}
    extension UICollectionView: ReloadableType {}
    

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87. extension NextPageLoadable
    where Self: UITableViewController {
    func loadNext() {
    //...
    self.tableView.reloadData()
    //...
    }
    }
    

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88. extension NextPageLoadable {
    func loadNext(view: ReloadableType) {
    //...
    view.reloadData()
    //...
    }
    }
    

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89. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    loadNext(reloadView: tableView)
    }
    }
    

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90. extension NextPageLoadable where Self: UITableViewController {
    func loadNext() {
    loadNext(reloadView: tableView)
    }
    }
    extension NextPageLoadable where Self: UICollectionViewController {
    func loadNext() {
    loadNext(reloadView: collectionView)
    }
    }
    

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91. • FriendsTableViewController →
    FriendsCollec5onViewController
    

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92. class FriendTableViewController: UITableViewController {
    var nextPageState = NextPageState()
    var data: [Friend] = []
    }
    extension FriendTableViewController: NextPageLoadable {
    func performLoad(
    successHandler: ([String], Bool, Int?) -> (),
    failHandler: () -> ())
    {
    client.send(FriendsRequest()) {
    result in
    if let result = result {
    successHandler(result.items,
    result.hasNext,
    result.items.last.id)
    } else {
    failHandler()
    }
    }
    }
    }
    

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93. class FriendCollectionViewController: UITableViewController {
    var nextPageState = NextPageState()
    var data: [Friend] = []
    }
    extension FriendCollectionViewController: NextPageLoadable {
    func performLoad(
    successHandler: ([String], Bool, Int?) -> (),
    failHandler: () -> ())
    {
    client.send(FriendsRequest()) {
    result in
    if let result = result {
    successHandler(result.items,
    result.hasNext,
    result.items.last.id)
    } else {
    failHandler()
    }
    }
    }
    }
    

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94. ViewController ၥᦶ
    

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95. ֵአܐᦓ๶ᕟᕢ ViewController
    • כ೮ᓌܔጱ ViewController ᖀಥ (ٺ੝ᖀಥ)
    

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96. ֵአܐᦓ๶ᕟᕢ ViewController
    • כ೮ᓌܔጱ ViewController ᖀಥ (ٺ੝ᖀಥ)
    • ֵአܐᦓ๶̿೪ᤰ̀ViewController ಅᵱᥝጱۑᚆ
    

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97. ֵአܐᦓ๶ᕟᕢ ViewController
    • כ೮ᓌܔጱ ViewController ᖀಥ (ٺ੝ᖀಥ)
    • ֵአܐᦓ๶̿೪ᤰ̀ViewController ಅᵱᥝጱۑᚆ
    • ਖ਼դᎱ޾ᨱձړᐶڊ ViewController
    

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98. ֵአܐᦓ๶ᕟᕢ ViewController
    • כ೮ᓌܔጱ ViewController ᖀಥ (ٺ੝ᖀಥ)
    • ֵአܐᦓ๶̿೪ᤰ̀ViewController ಅᵱᥝጱۑᚆ
    • ਖ਼դᎱ޾ᨱձړᐶڊ ViewController
    • ֵአ᯿຅ጱොဩਖ਼ܐᦓ᭑Ⴙ᭗አ۸
    

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99. ݳɾജ൐
    ֵአܐᦓଆۗද࠺դᎱᦡᦇ
    

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100. വគᩒා
     • Protocol-Oriented Programming in Swi4 - WWDC
     15 #408
     • Protocols with Associated Types - @alexisgallagher
     • Protocol Oriented Programming in the Real World -
     @_maHhewpalmer
     • PracIcal Protocol-Oriented-Programming -
     @natashatherobot
     

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101. ᨀᨀᘰލ
     FAQ
     Email: onev@onevcat.com, GitHub: onevcat
     

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