iOS RxSwift 4.2 如何使用 DelegateProxy 实现 CBCentralManager 的 Reactive 扩展？

Question

我在看this example of using reactive extensions with Core Bluetooth .但是，它是用 swift 3.0 编写的，并且在 Swift 4.2 中运行时存在许多错误。我有兴趣实现 CBCentralManager 的响应式扩展为我提供状态事件的 RX 流。

我的理解是，这允许代理从 CBCentralManager 接收委托(delegate)事件并使用 _stateBehaviorSubject: BehaviorSubject<CBManagerState>? 将它们传播给观察者。但是，该项目有太多错误，我无法弄清楚我应该在哪里削减以只保留我想要的功能。

如何使用 CBCentralManager 的 DelegateProxy 实现响应式(Reactive)扩展？

extension Reactive where Base: CBCentralManager {

  public var delegate: DelegateProxy {
    return RxCBCentralManagerDelegateProxy.proxyForObject(base)
  }

  public var state: Observable<CBManagerState> {
    let proxy = RxCBCentralManagerDelegateProxy.proxyForObject(base) //error here
    return proxy.stateBehaviorSubject.skip(1)
  }
}

Answer 1

这是 CBCentralManager 的有效实现

extension CBCentralManager : HasDelegate {
    public typealias Delegate = CBCentralManagerDelegate
}

class RxCBCentralManagerDelegateProxy
  : DelegateProxy<CBCentralManager, CBCentralManagerDelegate>
  , DelegateProxyType
  , CBCentralManagerDelegate
{

   internal let stateBehaviorSubject: BehaviorSubject<CBManagerState>

   init(centralManager: CBCentralManager) {
       let subject = BehaviorSubject(value: centralManager.state)
       stateBehaviorSubject = subject

       super.init(parentObject: centralManager, delegateProxy: RxCBCentralManagerDelegateProxy.self)
   }

   func centralManagerDidUpdateState(_ central: CBCentralManager) {
       stateBehaviorSubject.onNext(central.state)
       _forwardToDelegate?.centralManagerDidUpdateState(central)
   }

   static func registerKnownImplementations() {
       self.register { RxCBCentralManagerDelegateProxy(centralManager: $0) }
   }

   deinit {
       stateBehaviorSubject.on(.completed)
   }
}

extension Reactive where Base : CBCentralManager {
   var delegate: DelegateProxy<CBCentralManager, CBCentralManagerDelegate> {
       return RxCBCentralManagerDelegateProxy.proxy(for: base)
   }

   var state: ControlEvent<CBManagerState> {
       let source = (delegate as! RxCBCentralManagerDelegateProxy)
          .stateBehaviorSubject
          .skip(1)
       return ControlEvent(events: source)
   }
}