Swift3 简单代码swift到reactiveswift

了解如何转换代码：

struct CarModel {
    var model: String?
    var make: String?
    var kilowatts: Int?
    var photoURL: String?

    init(model: String, make: String, kilowatts: Int, photoURL: String) {
        self.model = model
        self.make = make
        self.kilowatts = kilowatts
        self.photoURL = photoURL
    }
} 

以及：

cocoa/ReactiveSwift。我念了一遍。关于Reactive的文档，但我不理解如何在代码中实现Reactive API。 谁知道我需要怎么做，请告诉我。

---

还有一位知道上一版本ReactiveCocoa/ReactiveSwift的好示例/示例/教程的人，请告诉我。

ReactiveCocoa用于将动态数据（保存在viewmodel中）绑定到ViewController的UI。如果数据不是动态的（如果viewmodel在viewcontroller的生命周期内没有更改），则根本不需要使用reactivecocoa。但是，如果您的

car

变量将发生变化，并且一个viewcontroller将用于显示多辆车，那么reactivecocoa将非常有用。您可以使用

MutableProperty

类来封装动态

car

变量，并创建在汽车属性更改时更新ViewController的信号

class CarViewModel {
  let car: MutableProperty<Car>

  init(_ car: Car) {
    self.car = MutableProperty(car)
  }

  var modelTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { $0.model }
  }

  var makeTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { $0.make }
  }

  var horsepowerTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { car in
      let HP = Int(round(Double(car.kilowatts) * CarViewModel.HPperKW))
      return "\(HP) HP"
    }
  }

  var titleTextSignal: SignalProducer<String, NoError> {
    return car.producer.map {  "\($0.make) \($0.model)" }
  }

  var photoURLSignal: SignalProducer<URL?, NoError> {
    return car.producer.map { URL(string: $0.photoURL) }
  }
}

因此，您可以看到，如果只需要在视图控制器中显示一个不变的汽车对象，则无需使用ReactiveCocoa--但是，如果您的viewmodel在viewcontroller的整个生命周期中都在更改，reactivecocoa允许您将可变数据绑定到UI，以便在数据更改时自动更新视图

class CarViewModel {
  let car: MutableProperty<Car>

  init(_ car: Car) {
    self.car = MutableProperty(car)
  }

  var modelTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { $0.model }
  }

  var makeTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { $0.make }
  }

  var horsepowerTextSignal: SignalProducer<String, NoError> {
    return car.producer.map { car in
      let HP = Int(round(Double(car.kilowatts) * CarViewModel.HPperKW))
      return "\(HP) HP"
    }
  }

  var titleTextSignal: SignalProducer<String, NoError> {
    return car.producer.map {  "\($0.make) \($0.model)" }
  }

  var photoURLSignal: SignalProducer<URL?, NoError> {
    return car.producer.map { URL(string: $0.photoURL) }
  }
}

class CarViewController: UIViewController {
  @IBOutlet modelLabel: UILabel!
  @IBOutlet makeLabel: UILabel!
  @IBOutlet horsepowerLabel: UILabel!
  @IBOutlet titleLabel: UILabel!
  @IBOutlet image: UIImageView!

  var viewModel: CarViewModel!

  override func viewDidLoad() {
    self.modelLabel.reactive.text <~ self.viewModel.modelTextSignal
    self.makeLabel.reactive.text <~ self.viewModel.makeTextSignal
    self.horsepowerLabel.reactive.text <~ self.viewModel.horsepowerTextSignal
    self.titleLabel.reactive.text <~ self.viewModel.titleTextSignal
    self.viewModel.photoURLSignal.startWithValues { [weak self] url in
      self?.setImageFromUrl(url)
    }
  }

  func displayNewCar() {
    self.viewModel.car.value = aRandomCar()
  }

  private func setImageFromUrl(url: URL?) {
    //download url and display in UIImageView
  }
  private func aRandomCar() -> Car {
    //return a Car object
  }
}