ReactiveSwift - 将“Action”绑定到“UIControl”

Question

我正在尝试将 Action 绑定到 UISwitch。

我使用以下代码创建了操作

    action = Action<UISwitch, Bool, NoError> { (input: UISwitch) -> SignalProducer<Bool, NoError> in
        return SignalProducer{ (observer, disposable) in
            observer.send(value: input.isOn)
            observer.sendCompleted()
        }
    }

但我无法将它连接到 UISwitch。

有人可以帮忙吗？

Answer 1

还有另一个 class CocoaAction 用于包装 Actions 并将它们连接到 UIControls（现在在 ReactiveCocoa 而不是核心 ReactiveSwift，因此如果您使用的是 RAC 5，则必须同时导入两者）

var switch: UISwitch!

//switch.addTarget() does not retain the target, so if we do not
//keep a strong reference here the cocoaAction will be deallocated
//at the end of viewDidLoad() and you will get unrecognized selector 
//errors when the switch tries to execute the action
var switchCocoaAction: CocoaAction!

override func viewDidLoad() {
  let action = Action<UISwitch, Bool, NoError> { (input: UISwitch) -> SignalProducer<Bool, NoError> in
    return SignalProducer { (observer, disposable) in
      observer.send(value: input.isOn)
      observer.sendCompleted()
    }
  }

  //unsafe because it will cast anyObject as! UISwitch
  self.switchCocoaAction = action.unsafeCocoaAction

  switch.addTarget(switchCocoaAction,
    action: CocoaAction.selector,
    forControlEvents: .ValueChanged
  ) 
}

但是，如果您想要的只是一个信号，只要它发生变化就会发出 switch.isOn 值，您可以使用内置 rac_signalForControlEvents

更轻松地完成此操作

func switchSignal() -> SignalProducer<Bool, NoError> {
  switch.rac_signalForControlEvents(.ValueChanged) //returns legacy RACsignal
    .toSignalProducer() //legacy RACSignal -> swift SignalProducer
    .flatMapError { _ in .empty } //NSError -> NoError, errors not possible here, so ignore them
    .map { ([=11=] as! UISwitch).isOn }
}

ReactiveSwift - 将“Action”绑定到“UIControl”

ReactiveSwift - Bind `Action` to `UIControl`

ios

swift

swift3

reactive