Question

Objective-C有一个setValue方法，允许开发人员通过它的名称为字段设置特定值。

如果不继承NSObject并且实际使用setValue方法，我怎么能在Swift中做到这一点？

Answer 1

您可以使用KVC这样做，afaik。看看这个很酷的例子： https://www.raywenderlich.com/163857/whats-new-swift-4

struct Lightsaber {
  enum Color {
    case blue, green, red
  }
  let color: Color
}

class ForceUser {
  var name: String
  var lightsaber: Lightsaber
  var master: ForceUser?

  init(name: String, lightsaber: Lightsaber, master: ForceUser? = nil) {
    self.name = name
    self.lightsaber = lightsaber
    self.master = master
  }
}

let sidious = ForceUser(name: "Darth Sidious", lightsaber: Lightsaber(color: .red))
let obiwan = ForceUser(name: "Obi-Wan Kenobi", lightsaber: Lightsaber(color: .blue))
let anakin = ForceUser(name: "Anakin Skywalker", lightsaber: Lightsaber(color: .blue), master: obiwan)

// Use keypath directly inline and to drill down to sub objects
let anakinSaberColor = anakin[keyPath: \ForceUser.lightsaber.color]  // blue

// Access a property on the object returned by key path
let masterKeyPath = \ForceUser.master
let anakinMasterName = anakin[keyPath: masterKeyPath]?.name  // "Obi-Wan Kenobi"

// AND HERE's YOUR ANSWER
// Change Anakin to the dark side using key path as a setter
anakin[keyPath: masterKeyPath] = sidious
anakin.master?.name // Darth Sidious

如何按属性名称设置Swift值？

1 个答案: