重构两个 switch case 语句的代码

Question

我正在处理一个 swift 项目，并且有一个问题要重构我的代码。

我正在编写代码来检查用户是否在应用程序中同时授权了摄像头和麦克风授权。我编写了以下代码，但我想（并且我希望）我可以重构代码，因为我认为下面的代码不清楚。我了解了基本的 Swift 语法，并逐渐了解了编译语言，但请告诉我是否有办法使其更具可读性或更易于编写。

我想在这里做的是......

• 检查摄像头和麦克风是否都被授权。

• 如果两者都被授权，则使用 showNextVC() 显示视图控制器。

• 如果其中一项或两项均未获得授权，则使用 showConfigurationAlert 显示警报

  func checkAuthStatus(){
      checkCameraStatus()
  }
  
  func checkCameraStatus() {
      switch AVCaptureDevice.authorizationStatus(for: .video) {
      case .notDetermined:
          print("not Determined")
          AVCaptureDevice.requestAccess(for: .video) { granted in
              if granted {
                  print("Now it's granted")
              }
          }
      case .restricted:
          print("restricted")
          showConfigurationAlert(for: "camera")
      case .denied:
          print("denied")
          showConfigurationAlert(for: "camera")
      case .authorized:
          checkMicrophoneStatus()
      @unknown default:
          print("unknown")
      }
  
  }
  
  func checkMicrophoneStatus() {
      switch AVCaptureDevice.authorizationStatus(for: .audio){
      case .notDetermined:
          AVCaptureDevice.requestAccess(for: .audio) { granted in
              if granted {
                  print("Now it's granted")
              }
          }
      case .restricted:
          print("restricted")
          showConfigurationAlert(for: "microphone")
      case .denied:
          print("denied")
          showConfigurationAlert(for: "microphone")
      case .authorized:
          print(("authorized"))
          showNextVC()
      @unknown default:
          print("unknown")
      }
  }
  

我所做的是，首先在 checkAuthStatus 中检查相机授权，然后，如果相机被授权，则触发 checkMicrophoneStatus() 以检查麦克风授权。 我认为这段代码不清楚的原因是，我只在 checkAuthStatus() 函数中编写了一个检查相机授权的函数。我想如果我能写出类似的东西很清楚

func checkAuthStatus(){
    // check both cameara and microphone is authorized.
    // if both of them are authorized, show next VC with showNextVC() function.
}

Answer 1

一种方法是为这两个函数添加一个onAuthorised 闭包参数。这两个checkXXXStatus 函数也有很多共同点。我们不需要重复 switch 语句。

func checkMediaStatus(type: AVMediaType, deviceName: String, onAuthorised: (() -> Void)?) {
    switch AVCaptureDevice.authorizationStatus(for: type){
    case .notDetermined:
        AVCaptureDevice.requestAccess(for: type) { granted in
            if granted {
                print("Now it's granted")
            }
        }
    case .restricted:
        print("restricted")
        showConfigurationAlert(for: deviceName)
    case .denied:
        print("denied")
        showConfigurationAlert(for: deviceName)
    case .authorized:
        print(("authorized"))
        onAuthorised?()
    @unknown default:
        print("unknown")
    }
}

func checkMicrophoneStatus(onAuthorised: (() -> Void)?) {
    checkMediaStatus(type: .audio, deviceName: "microphone", onAuthorised: onAuthorised)
}

func checkCameraStatus(onAuthorised: (() -> Void)?) {
    checkMediaStatus(type: .video, deviceName: "camera", onAuthorised: onAuthorised)
}

那么checkAuthStatus可以写成：

func checkAuthStatus(){
    checkCameraStatus {
        self.checkMicrophoneStatus {
            self.showNextVC()
        }
    }
}

还请注意，您可能还想在 requestAccess 完成处理程序中调用 onAuthorised 和 showConfigurationAlert。我认为这是一个更好的设计。

if granted {
    print("Now it's granted")
    onAuthorised?()
} else {
    showConfigurationAlert(for: deviceName)
}

Answer 2

我认为您正在寻找这样的东西：

let videoStatus = AVCaptureDevice.authorizationStatus(for: .video)
let audioStatus = AVCaptureDevice.authorizationStatus(for: .audio)

switch (videoStatus, audioStatus) {
case (.authorized, .authorized): showNextVC()
case (.authorized, _): showConfigurationAlert(for: "microphone")
case (_, .authorized): showConfigurationAlert(for: "camera")
default: print(videoStatus, audioStatus)
}

您可以同时检查两种情况并处理您喜欢的每种情况

Answer 3

您可以更改 checkCameraStatus() 和 checkMicrophoneStatus() 以返回 bool 并在 checkAuthStatus() 内部更改为：

func checkAuthStatus(){
    let cameraAuthorised = checkCameraStatus()
    let micAuthorised = checkMicrophoneStatus()

    if (cameraAuthorised && micAuthorised) {
        showNextVC()
    }
 }