RxSwift特点
swift是一门静态语言，不像OC那样可以动态的传输数据发送消息，RxSwift可以弥补swift的这种语言特性。
RxSwift函数响应式编程思想，其代码可读性强、复用性高、容易理解、很稳定，抽象了异步编程统一代码风格。
函数响应式编程FRP(Function Reactive Programming)
1、函数式是以函数作为参数的编程方式
函数式例子：
//获取大于3的数字之后将其加1，并取结果中的偶数
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)
}
}
}
//函数式写法：filter函数参数是一个闭包，$0 > 3表示取数组第一个值大于3
array.filter { $0 > 3 }
.filter { ($0 + 1) % 2 == 0 }
.forEach { print($0) }
对比之后发现函数式可读性和可操作性更强
2、响应式：RxSwift 简单使用
KVO
KVO是runtime的运行时机制，在静态语言swift里无法执行，需要加上@objc dynamic才能执行，@objc的意思是使用OC访问这段代码，dynamic是开启运行时功能
swift写法：
// 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)
}
/*
输出结果：
Optional([__C.NSKeyValueChangeKey(_rawValue: new): ly + , __C.NSKeyValueChangeKey(_rawValue: kind): 1])
Optional([__C.NSKeyValueChangeKey(_rawValue: new): ly + + , __C.NSKeyValueChangeKey(_rawValue: kind): 1])
*/
RxSwift写法：
// ViewController.swift
func setupKVO() {
self.person.rx.observeWeakly(String.self, "name")
.subscribe(onNext: { (value) in
print(value as Any)
})
.disposed(by: disposeBag)
}
/*
输出结果：
Optional("ly")
Optional("ly + ")
Optional("ly + + ")
*/
Button
swift写法：
func setupButton() {
self.button.addTarget(self, action: #selector(buttonClick), for: .touchUpInside)
}
@objc func buttonClick() {
print("点击了按钮")
}
RxSwift写法：
//业务逻辑和功能逻辑在一起
func setupButton() {
self.button.rx.tap
.subscribe(onNext: { () in
print("点击事件")
})
.disposed(by: disposeBag)
self.button.rx.controlEvent(.touchUpInside)
.subscribe(onNext: { () in
print("点击事件1")
})
.disposed(by: disposeBag)
}
- rx实现：
//协议拓展
extension ReactiveCompatible {
/// Reactive extensions. //提供给外界的属性
public static var rx: RxSwift.Reactive<Self>.Type
/// Reactive extensions.
public var rx: RxSwift.Reactive<Self>
}
/// A type that has reactive extensions. //ReactiveCompatible协议，实现此协议的类都会拥有rx属性
public protocol ReactiveCompatible {
/// Extended type
associatedtype ReactiveBase //关联类型
@available(*, deprecated, message: "Use `ReactiveBase` instead.")
typealias CompatibleType = ReactiveBase
/// Reactive extensions. //rx的get和set方法，协议属性
static var rx: Reactive<ReactiveBase>.Type { get set }
/// Reactive extensions. //协议方法
var rx: Reactive<ReactiveBase> { get set }
}
/// Extend NSObject with `rx` proxy. //协议实现，NSObject拓展实现协议
extension NSObject : ReactiveCompatible {
}
TextField
swift写法
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
}
}
/*
输出结果：
p
o
i
u
y
*/
RxSwift写法：
func setupTextField() {
self.textField.rx.text.orEmpty
.subscribe(onNext: { (text) in
print(text)
})
.disposed(by: disposeBag)
//将textField输入的值绑定到button的title
self.textField.rx.text
.bind(to: self.button.rx.title())
}
/*
输出结果：
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将拿到的值赋值给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写法：
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写法：
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手势
swift写法：
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写法：
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，监听键盘避免遮挡输入框
swift写法：
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写法：
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定时器
swift写法：（scrollview滚动时定时器会停止计时）
let timerT = Timer.init(timeInterval: 1, repeats: true) { (kTimer) in
print(kTimer)
}
RunLoop.current.add(timerT, forMode: .default)
timerT.fire()
RxSwift写法：（scrollview滚动事件不影响定时器计时，实际是根据interval发送响应来执行操作）
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实现
public static func interval(_ period: RxTimeInterval, scheduler: SchedulerType)
-> Observable<Element> {
return Timer(
dueTime: period,
period: period,
scheduler: scheduler
)
}
- timer实现，TimerSink()实现定时
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()实现，通过state的改变达到计时的目的
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网络请求
swift写法：
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()
}
/*
输出结果：
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写法：
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)
}
/*
输出结果：
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实现：将request和dataTask放在函数里实现，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)
}
}
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