RxSwift概念系列入门
基本核心概念 Observable
Observable的层级概念
public class Observable<Element> : ObservableType ---->
public protocol ObservableType: ObservableConvertibleType
ObservableType的核心作用
1 定义统一的方法
func subscribe<Observer: ObserverType>(_ observer: Observer) -> Disposable where Observer.Element == Element2 使子类统一具有可观察功能
extension ObservableType {
/// Default implementation of converting `ObservableType` to `Observable`.
public func asObservable() -> Observable<Element> {
// temporary workaround
//return Observable.create(subscribe: self.subscribe)
return Observable.create { o in
return self.subscribe(o)
}
}
}常用使用
//Observable一系列方法
Observable.from(["1","2"]).subscribe{
print($0)
}.dispose()
Observable.of("1","2").subscribe{
print($0)
}.dispose()
Observable<String>.create { (observer) -> Disposable in
observer.onNext("1")
observer.onCompleted()
return Disposables.create()
}.subscribe{
print($0)
}.dispose()
Observable.range(start: 0, count: 10).subscribe{
print($0)
}
var times = 0
let factory = Observable<Any>.deferred {
times+=1
return Observable.of(0..<times)
}
for i in 0...10{
factory.subscribe{
print($0)
}
}
订阅模式
//订阅
Observable.of("A","B").subscribe{
event in
print(event)
}
//可以缩写省略
Observable.of("A" ... "D").subscribe{
print($0)
}
订阅可以关注整个过程或者某过程某一部分
//订阅显示整个过程
Observable.of("A","B","C").subscribe(onNext: { (item) in
print(item)
}, onError: { (error) in
print(error)
}, onCompleted: {
}) {
}
//关注某一个过程
Observable.of("A").subscribe(onNext: { (item) in
print(item)
})Variables的使用
let disposeBag = DisposeBag()
struct Person {
var name: Variable<String> //再次修改的时候会重新发送single
}
let scott = Person(name: Variable("Scott"))
let lori = Person(name: Variable("Lori"))
let person = Variable(scott)
person.asObservable().flatMap { (p) -> Observable<String> in
return p.name.asObservable()
}.subscribe(onNext: { (name) in
print(name)
}).disposed(by: disposeBag)
person.value = lori
scott.name.value = "Eric"通过Variable可以监听内部Value值修改变化，如上栗中 person.value = lori scott.name.value = "Eric"进行修改时均会一起注册监听的回调
更直观的例子
let search = Variable("iOS")
search.asObservable().map{
$0.lowercased()
}.distinctUntilChanged()
.subscribe { (e:Event<String>) in
print(e)
}.disposed(by: disposeBag)
search.value = "IOS"
search.value = "Rx"当修改search的value时订阅回调
