我想知道什么是最好的做法是什么当我想要一些功能公开,一些在我内部使用协议时.我正在写一个 AudioManager在Swift 3中包装AVPlayer作为框架.我想要一些公开的方法,例如使用AudioManager的ViewController可以访问某些方法,但某些方法不会暴露在框架之外 – >即具有内部访问修饰符而不是公共修饰符.我正在使用协议驱动设计编写框架,几乎每个部分都应该有一个协议.所以协议正在与框架内的协议进行通信.例如.主类 – AudioManager – 有一个AudioPlayer,应该可以调用它上面的一些内部函数,例如暂停(原因:),但该方法应该是内部的,不会暴露在框架之外.这是一个例子.

internal enum PauseReason {
    case byUser
    case routeChange
}

// Compilation error: `Public protocol cannot refine an internal protocol`
public protocol AudioPlayerProtocol: InternalAudioPlayerProtocol { 
   func pause() // I want 
}

internal protocol InternalAudioPlayerProtocol {
    func pause(reason: PauseReason) // Should only be accessible within the framework
}

public class AudioPlayer: AudioPlayerProtocol {
    public func pause() {
        pause(reason: .byUser)
    }

    // This would probably not compile because it is inside a public class...
    internal func pause(reason: PauseReason) { //I want this to be internal
        // save reason and to stuff with it later on
    }
}

public protocol AudioManagerProtocol {
    var audioPlayer: AudioPlayerProtocol { get }
}

public class AudioManager: AudioManagerProtocol {
    public let audioPlayer: AudioPlayerProtocol

    init() {
        audioPlayer = AudioPlayer()
        NotificationCenter.default.addObserver(self,selector: #selector(handleRouteChange(_:)),name: NSNotification.Name.AVAudioSessionRouteChange,object: nil)
    }

    func handleRouteChange(_ notification: Notification) {
        guard
        let userInfo = notification.userInfo,let reasonRaw = userInfo[AVAudioSessionRouteChangeReasonKey] as? NSNumber,let reason = AVAudioSessionRouteChangeReason(rawValue: reasonRaw.uintValue)
        else { print("what could not get route change") }
        switch reason {
        case .oldDeviceUnavailable:
            pauseBecauSEOfRouteChange()
        default:
            break
        }
    }
}

private extension AudioManager {
    func pauseBecauSEOfRouteChange() {
        audioPlayer.pause(reason: .routeChange)
    }
}

// Outside of Audio framework
class PlayerViewController: UIViewController {
    fileprivate let audioManager: AudioManagerProtocol 
    @IBAction didPressPauseButton(_ sender: UIButton) {
        // I want the `user of the Audio framwwork` (in this case a ViewController)
        // to only be able to `see` `pause()` and not `pause(reason:)` 
        audioManager.audioPlayer.pause()
    }
}

我知道我可以通过将pauseBecauSEOfRouteChange方法更改为如下所示来实现它：

func pauseBecauSEOfRouteChange() {
    guard let internalPlayer = audioPlayer as? InternalAudioPlayerProtocol else { return }
    internalPlayer.pause(reason: .routeChange)
}

但我想知道是否有更优雅的解决方案？像标记AudioPlayerProtocol精炼InternalAudioPlayerProtocol …

或者你们的程序员如何做到这一点？如果框架没有公开供内部使用的方法和变量,那么框架会更漂亮！

谢谢！

public class AudioPlayer: AudioPlayerProtocol {
    public func pause() {
        pause(reason: .byUser)
    }

    internal func pause(reason: PauseReason) {
    }
}