觀察 ViewWillAppear（遷移 RXSwift 來合並）

Question

extension Reactive where Base: UIViewController {
    var viewWillAppear: Observable<Void> {
        sentMessage(#selector(UIViewController.viewWillAppear(_:)))
            .filter { [weak base] _ in
                if base?.isImageViewerPresented == true {
                    return false
                }
                return true
            }
            .mapToVoid()
    }
}

我想像self.viewWillApplerPublisher一樣觀察 viewWillAppear 請幫助如何觀察它

Answer 1

extension Reactive where Base: UIViewController {

public var viewWillAppear: ControlEvent<Void> {
    let source = self.methodInvoked(#selector(Base.viewWillAppear))
        .map { _ in }
    return ControlEvent(events: source)
  }

}