How to do delegate with RxSwift

[onmyway133]

We can use DelegateProxy and DelegateProxyType to make beautiful delegate with RxSwift. But in some other cases, we can just create a custom class with PublishSubject.

This is how we can make rx out of UIApplication life cycle events

class LifeCycle {
  let didEnterBackground = PublishSubject<Void>()
  let willEnterForeground  = PublishSubject<Void>()
  let didBecomeActive = PublishSubject<Void>()
  let willResignActive = PublishSubject<Void>()

  init() {
    let center = NotificationCenter.default
    let app = UIApplication.shared

    center.addObserver(forName: Notification.Name.UIApplicationDidEnterBackground,
                       object: app, queue: .main, using: { [weak self] _ in
      self?.didEnterBackground.onNext(())
    })

    center.addObserver(forName: Notification.Name.UIApplicationWillEnterForeground,
                       object: app, queue: .main, using: { [weak self] _ in
      self?.willEnterForeground.onNext(())
    })

    center.addObserver(forName: Notification.Name.UIApplicationDidBecomeActive,
                       object: app, queue: .main, using: { [weak self] _ in
      self?.didBecomeActive.onNext(())
    })

    center.addObserver(forName: Notification.Name.UIApplicationWillResignActive,
                       object: app, queue: .main, using: { [weak self] _ in
      self?.willResignActive.onNext(())
    })
  }
}

Usage

let lifeCycle = LifeCycle()
lifeCycle.didBecomeActive
      .bindNext({ [weak self] in
        self?.viewModel.reloadProfile()
      })
      .disposed(by: bag)