RxSwift发送及订阅 Subjects、Variables代码示例

let sub = PublishSubject<String>()

sub.onNext("订阅之前的不能接收到")

sub.subscribe { event in
  print(event.element)
//Optional("订阅之后的可以接收到")
//nil
}.disposed(by: disposeBag)

sub.onNext("订阅之后的可以接收到")
//结束
sub.onCompleted()
/// 结束之后添加的订阅能收到 completed
sub.subscribe { event in
  print(event)
}
sub.onNext("结束后发的都收不到")

let sub = BehaviorSubject(value: "默认值")

sub.subscribe { event in
  print("订阅1", event)
}.disposed(by: disposeBag)
sub.onNext("发送1")
sub.subscribe { event in
  print("订阅2", event)
}.disposed(by: disposeBag)
sub.onCompleted()
sub.subscribe { event in
  print("订阅3", event)
}.disposed(by: disposeBag)

订阅1 next(默认值)
订阅1 next(发送1)
订阅2 next(发送1)
订阅1 completed
订阅2 completed
订阅3 completed

let sub = ReplaySubject<String>.create(bufferSize: 2)

sub.subscribe { event in
  print("订阅1", event)
}.disposed(by: disposeBag)
sub.onNext("发送1")
print("-------")
sub.subscribe { event in
  print("订阅2", event)
}.disposed(by: disposeBag)

sub.onNext("发送2")
sub.onNext("发送3")
sub.onNext("发送4")
print("-------")
sub.subscribe { event in
  print("订阅3", event)
}.disposed(by: disposeBag)
sub.onCompleted()
print("-------")
/// 不仅会收到最后的两个 event 还有 Completed
sub.subscribe { event in
  print("订阅4", event)
}

订阅1 next(发送1)
-------
订阅2 next(发送1)
订阅1 next(发送2)
订阅2 next(发送2)
订阅1 next(发送3)
订阅2 next(发送3)
订阅1 next(发送4)
订阅2 next(发送4)
-------
订阅3 next(发送3)
订阅3 next(发送4)
订阅1 completed
订阅2 completed
订阅3 completed
-------
订阅4 next(发送3)
订阅4 next(发送4)
订阅4 completed

let sub = BehaviorRelay(value: "初始值")

sub.subscribe { event in
  print("第一次订阅", event)
}.disposed(by: disposeBag)
sub.accept("新值1")
sub.subscribe { event in
  print("第二次订阅", event)
}.disposed(by: disposeBag)