RxSwift 簡(jiǎn)單使用和與swift的寫(xiě)法對(duì)比

RxSwift特點(diǎn)

swift是一門(mén)靜態(tài)語(yǔ)言，不像OC那樣可以動(dòng)態(tài)的傳輸數(shù)據(jù)發(fā)送消息，RxSwift可以彌補(bǔ)swift的這種語(yǔ)言特性。
RxSwift函數(shù)響應(yīng)式編程思想，其代碼可讀性強(qiáng)、復(fù)用性高、容易理解、很穩(wěn)定，抽象了異步編程統(tǒng)一代碼風(fēng)格。

函數(shù)響應(yīng)式編程FRP(Function Reactive Programming)

1、函數(shù)式是以函數(shù)作為參數(shù)的編程方式

函數(shù)式例子：

        //獲取大于3的數(shù)字之后將其加1，并取結(jié)果中的偶數(shù)

        let array = [1, 2, 3, 4, 5, 6, 7]
        for num in array {
            if (num > 3) {
                let number = num + 1
                if (number % 2 == 0) {
                    print(number)
                }
            }
        }

        //函數(shù)式寫(xiě)法：filter函數(shù)參數(shù)是一個(gè)閉包，$0 > 3表示取數(shù)組第一個(gè)值大于3
        array.filter { $0 > 3 }
            .filter { ($0 + 1) % 2 == 0 }
            .forEach { print($0) }

對(duì)比之后發(fā)現(xiàn)函數(shù)式可讀性和可操作性更強(qiáng)

2、響應(yīng)式：RxSwift 簡(jiǎn)單使用
KVO

KVO是runtime的運(yùn)行時(shí)機(jī)制，在靜態(tài)語(yǔ)言swift里無(wú)法執(zhí)行，需要加上@objc dynamic才能執(zhí)行，@objc的意思是使用OC訪問(wèn)這段代碼，dynamic是開(kāi)啟運(yùn)行時(shí)功能

swift寫(xiě)法：

//  LYPerson.swift
class LYPerson: NSObject {
    @objc dynamic var name:String = "ly"
}

//  ViewController.swift
    override func viewDidLoad() {
        super.viewDidLoad()
        self.setupKVO()
    }
    func setupKVO() {
        self.person.addObserver(self, forKeyPath: "name", options: .new, context: nil)
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        person.name = "\(person.name) + "
    }
    
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        print(change as Any)
    }
    
    deinit {
        self.person.removeObserver(self, forKeyPath: "name", context: nil)
    }

/*
輸出結(jié)果：
Optional([__C.NSKeyValueChangeKey(_rawValue: new): ly + , __C.NSKeyValueChangeKey(_rawValue: kind): 1])
Optional([__C.NSKeyValueChangeKey(_rawValue: new): ly +  + , __C.NSKeyValueChangeKey(_rawValue: kind): 1])
*/

RxSwift寫(xiě)法：

//  ViewController.swift
    func setupKVO() {
        self.person.rx.observeWeakly(String.self, "name")
            .subscribe(onNext: { (value) in
                print(value as Any)
            })
            .disposed(by: disposeBag)
    }

/*
輸出結(jié)果：
Optional("ly")
Optional("ly + ")
Optional("ly +  + ")
*/
Button

swift寫(xiě)法：

func setupButton() {
        self.button.addTarget(self, action: #selector(buttonClick), for: .touchUpInside)
    }
@objc func buttonClick() {
        print("點(diǎn)擊了按鈕")
    }

RxSwift寫(xiě)法：

//業(yè)務(wù)邏輯和功能邏輯在一起
func setupButton() {
        self.button.rx.tap
            .subscribe(onNext: { () in
               print("點(diǎn)擊事件")
            })
            .disposed(by: disposeBag)

        self.button.rx.controlEvent(.touchUpInside)
            .subscribe(onNext: { () in
                print("點(diǎn)擊事件1")
            })
            .disposed(by: disposeBag)
    }
  • rx實(shí)現(xiàn)：
//協(xié)議拓展
extension ReactiveCompatible {

    /// Reactive extensions. //提供給外界的屬性
    public static var rx: RxSwift.Reactive<Self>.Type

    /// Reactive extensions.
    public var rx: RxSwift.Reactive<Self>
}

/// A type that has reactive extensions. //ReactiveCompatible協(xié)議，實(shí)現(xiàn)此協(xié)議的類(lèi)都會(huì)擁有rx屬性
public protocol ReactiveCompatible {
    /// Extended type
    associatedtype ReactiveBase //關(guān)聯(lián)類(lèi)型

    @available(*, deprecated, message: "Use `ReactiveBase` instead.")
    typealias CompatibleType = ReactiveBase

    /// Reactive extensions. //rx的get和set方法，協(xié)議屬性
    static var rx: Reactive<ReactiveBase>.Type { get set }

    /// Reactive extensions. //協(xié)議方法
    var rx: Reactive<ReactiveBase> { get set }
}

/// Extend NSObject with `rx` proxy. //協(xié)議實(shí)現(xiàn)，NSObject拓展實(shí)現(xiàn)協(xié)議
extension NSObject : ReactiveCompatible {
}
TextField

swift寫(xiě)法

class ViewController: UIViewController, UITextFieldDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        self.setupTextField()
    }

    func setupTextField() {
        self.textField.delegate = self
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        print(string)
        return true
    }
}
/*
輸出結(jié)果：
p
o
i
u
y
*/

RxSwift寫(xiě)法：

func setupTextField() {
        self.textField.rx.text.orEmpty
            .subscribe(onNext: { (text) in
                print(text)
            })
            .disposed(by: disposeBag)

//將textField輸入的值綁定到button的title
        self.textField.rx.text
        .bind(to: self.button.rx.title())
    }
/*
輸出結(jié)果：
p
po
poi
poiu
poiuy
*/
  • bind方法
/**
     Creates new subscription and sends elements to observer(s).
     In this form, it's equivalent to the `subscribe` method, but it better conveys intent, and enables
     writing more consistent binding code.
     - parameter to: Observers to receives events.
     - returns: Disposable object that can be used to unsubscribe the observers.
     */
    public func bind<Observer>(to observers: Observer...) -> Disposable where Observer : ObserverType, Self.Element == Observer.Element
  • title()方法
/// Reactive wrapper for `setTitle(_:for:)` //Binder將拿到的值賦值給button的title
    public func title(for controlState: UIControl.State = []) -> Binder<String?> {
        return Binder(self.base) { button, title -> Void in
            button.setTitle(title, for: controlState)
        }
    }
ScrollView

swift寫(xiě)法：

class ViewController: UIViewController, UIScrollViewDelegate {
    func setupScrollView() {
        self.scrollView.delegate = self
    }
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        self.view.backgroundColor = UIColor.init(white: scrollView.contentOffset.y/60, alpha: 1.0)
    }
}

RxSwift寫(xiě)法：

func setupScrollView() {
        self.scrollView.rx.contentOffset
            .subscribe(onNext: { [weak self](content) in
                self?.view.backgroundColor = UIColor.init(white: content.y/60, alpha: 1.0)
            })
            .disposed(by: disposeBag)
    }
gesture手勢(shì)

swift寫(xiě)法：

func setupGesture() {
        let tap = UITapGestureRecognizer()
        self.label.isUserInteractionEnabled = true
        self.label.addGestureRecognizer(tap)
        
        tap.addTarget(self, action: #selector(tapLabel(_ :)))
    }
    
    @objc func tapLabel(_ gesture: UITapGestureRecognizer) {
        print(gesture.view)
    }

RxSwift寫(xiě)法：

func setupGesture() {
        let tap = UITapGestureRecognizer()
        self.label.isUserInteractionEnabled = true
        self.label.addGestureRecognizer(tap)
        
        tap.rx.event.subscribe(onNext: { (tap) in
            print(tap.view)
        })
        .disposed(by: disposeBag)
    }
NotificationCenter通知，監(jiān)聽(tīng)鍵盤(pán)避免遮擋輸入框

swift寫(xiě)法：

func setupNotification() {
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillShow(_ :)),
                                               name: UIResponder.keyboardWillShowNotification,
                                               object: nil)
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillHide(_ :)),
                                               name: UIResponder.keyboardWillHideNotification,
                                               object: nil)
    }
    
    @objc func keyboardWillShow(_ notification: Notification) {
        DispatchQueue.main.async {
            
            let user_info = notification.userInfo
            let keyboardRect = (user_info?[UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
            
            let y = keyboardRect.origin.y
            let y2 = (self.textField?.frame.origin.y)! + (self.textField?.frame.size.height)! + 5
            let offset_y = y2 > y ? (y2-y):(0)
            
            UIView.animate(withDuration: 0.25, animations: {
                self.view.center = CGPoint.init(x: self.view.center.x, y: self.view.center.y - offset_y)
            })
        }
    }
    
    @objc func keyboardWillHide(_ notification: Notification) {
        DispatchQueue.main.async {
            self.view.center = CGPoint.init(x: self.view.center.x, y: self.view.frame.height/2)
        }
    }
    deinit {
        NotificationCenter.default.removeObserver(self)
    }

RxSwift寫(xiě)法：

func setupNotification() {
        NotificationCenter.default.rx
            .notification(UIResponder.keyboardWillShowNotification)
            .subscribe(onNext: { (noti) in
                print(noti)
            let user_info = noti.userInfo
            let keyboardRect = (user_info?[UIResponder.keyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
            
            let y = keyboardRect.origin.y
            let y2 = (self.textField?.frame.origin.y)! + (self.textField?.frame.size.height)! + 5
            let offset_y = y2 > y ? (y2-y):(0)
            
            UIView.animate(withDuration: 0.25, animations: {
                self.view.center = CGPoint.init(x: self.view.center.x, y: self.view.center.y - offset_y)
            })
        })
        .disposed(by: disposeBag)
        NotificationCenter.default.rx
            .notification(UIResponder.keyboardWillHideNotification)
            .subscribe(onNext: { (noti) in
                print(noti)
                self.view.center = CGPoint.init(x: self.view.center.x, y: self.view.frame.height/2)
            })
        .disposed(by: disposeBag)
    }
timer定時(shí)器

swift寫(xiě)法：（scrollview滾動(dòng)時(shí)定時(shí)器會(huì)停止計(jì)時(shí)）

let timerT = Timer.init(timeInterval: 1, repeats: true) { (kTimer) in
            print(kTimer)
        }
        RunLoop.current.add(timerT, forMode: .default)
        timerT.fire()

RxSwift寫(xiě)法：（scrollview滾動(dòng)事件不影響定時(shí)器計(jì)時(shí)，實(shí)際是根據(jù)interval發(fā)送響應(yīng)來(lái)執(zhí)行操作）

var timer: Observable<Int>!

func setupTimer() {
        timer = Observable<Int>.interval(1, scheduler: MainScheduler.instance)
        timer.subscribe(onNext: { (num) in
            print(num)
        })
        .disposed(by: disposeBag)
    }
  • interval實(shí)現(xiàn)
public static func interval(_ period: RxTimeInterval, scheduler: SchedulerType)
        -> Observable<Element> {
        return Timer(
            dueTime: period,
            period: period,
            scheduler: scheduler
        )
    }
  • timer實(shí)現(xiàn)，TimerSink()實(shí)現(xiàn)定時(shí)
final private class Timer<Element: RxAbstractInteger>: Producer<Element> {
    fileprivate let _scheduler: SchedulerType
    fileprivate let _dueTime: RxTimeInterval
    fileprivate let _period: RxTimeInterval?

    init(dueTime: RxTimeInterval, period: RxTimeInterval?, scheduler: SchedulerType) {
        self._scheduler = scheduler
        self._dueTime = dueTime
        self._period = period
    }

    override func run<Observer: ObserverType>(_ observer: Observer, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where Observer.Element == Element {
        if self._period != nil {
            let sink = TimerSink(parent: self, observer: observer, cancel: cancel)
            let subscription = sink.run()
            return (sink: sink, subscription: subscription)
        }
        else {
            let sink = TimerOneOffSink(parent: self, observer: observer, cancel: cancel)
            let subscription = sink.run()
            return (sink: sink, subscription: subscription)
        }
    }
}
  • TimerSink()實(shí)現(xiàn)，通過(guò)state的改變達(dá)到計(jì)時(shí)的目的
final private class TimerSink<Observer: ObserverType> : Sink<Observer> where Observer.Element : RxAbstractInteger  {
    typealias Parent = Timer<Observer.Element>

    private let _parent: Parent
    private let _lock = RecursiveLock()

    init(parent: Parent, observer: Observer, cancel: Cancelable) {
        self._parent = parent
        super.init(observer: observer, cancel: cancel)
    }

    func run() -> Disposable {
        return self._parent._scheduler.schedulePeriodic(0 as Observer.Element, startAfter: self._parent._dueTime, period: self._parent._period!) { state in
            self._lock.lock(); defer { self._lock.unlock() }
            self.forwardOn(.next(state))
            return state &+ 1
        }
    }
}
network網(wǎng)絡(luò)請(qǐng)求

swift寫(xiě)法：

func setupNetwork() {
    let url = URL(string: "https://www.baidu.com")
        URLSession.shared.dataTask(with: url!) { (data, response, error) in
            print(String.init(data: data!, encoding: .utf8))
        }.resume()
}
/*
輸出結(jié)果：
Optional("<html>\r\n<head>\r\n\t<script>\r\n\t\tlocation.replace(location.href.replace(\"https://\",\"http://\"));\r\n\t</script>\r\n</head>\r\n<body>\r\n\t<noscript><meta http-equiv=\"refresh\" content=\"0;url=http://www.baidu.com/\"></noscript>\r\n</body>\r\n</html>")
*/

RxSwift寫(xiě)法：

let url = URL(string: "https://www.baidu.com")
func setupNetwork() {
    URLSession.shared.rx.response(request: URLRequest(url: url!))
            .subscribe(onNext: { (response, data) in
                print(String.init(data: data, encoding: .utf8))
            })
            .disposed(by: disposeBag)
}
/*
輸出結(jié)果：
curl -X GET 
"https://www.baidu.com" -i -v
Success (1246ms): Status 200
Optional("<html>\r\n<head>\r\n\t<script>\r\n\t\tlocation.replace(location.href.replace(\"https://\",\"http://\"));\r\n\t</script>\r\n</head>\r\n<body>\r\n\t<noscript><meta http-equiv=\"refresh\" content=\"0;url=http://www.baidu.com/\"></noscript>\r\n</body>\r\n</html>")
*/
  • response實(shí)現(xiàn)：將request和dataTask放在函數(shù)里實(shí)現(xiàn)，返回response、data和error信息
public func response(request: URLRequest) -> Observable<(response: HTTPURLResponse, data: Data)> {
        return Observable.create { observer in

            // smart compiler should be able to optimize this out
            let d: Date?

            if Logging.URLRequests(request) {
                d = Date()
            }
            else {
               d = nil
            }

            let task = self.base.dataTask(with: request) { data, response, error in

                if Logging.URLRequests(request) {
                    let interval = Date().timeIntervalSince(d ?? Date())
                    print(convertURLRequestToCurlCommand(request))
                    #if os(Linux)
                        print(convertResponseToString(response, error.flatMap { $0 as NSError }, interval))
                    #else
                        print(convertResponseToString(response, error.map { $0 as NSError }, interval))
                    #endif
                }
                
                guard let response = response, let data = data else {
                    observer.on(.error(error ?? RxCocoaURLError.unknown))
                    return
                }

                guard let httpResponse = response as? HTTPURLResponse else {
                    observer.on(.error(RxCocoaURLError.nonHTTPResponse(response: response)))
                    return
                }

                observer.on(.next((httpResponse, data)))
                observer.on(.completed)
            }

            task.resume()

            return Disposables.create(with: task.cancel)
        }
    }

參考鏈接：
Swift監(jiān)聽(tīng)鍵盤(pán)通知以及做出一些處理
55 - Swift 之 Timer (NSTimer )定時(shí)器

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