swift - RxSwift PublishSubject 类型 Optional startWith nil

Question

我正在努力实现以下目标:

let reachedTopMostMessage = PublishSubject<Int?>()
reachedTopMostMessage.startWith(nil).subscribeNext { (_) in
    //
}

但是编译器报错:

'Int?' (aka 'Optional') is not convertible to '(Int?...)' (aka '(Optional...)')

这是怎么回事？

Answer 1

使用 Optional<Int>()创建一个 nil Int? ，不只是 nil .

let reachedTopMostMessage = PublishSubject<Int?>()
reachedTopMostMessage.startWith(Optional<Int>()).subscribeNext { (_) in
    //
}