Swift 5: 'self' 在 'self.init' 调用之前使用

Question

我正在尝试使用所需的便捷可失败初始化程序。这是我正在使用的代码：

public init(authState: OIDAuthState, config: [String: String], accessibility: CFString = kSecAttrAccessibleWhenUnlockedThisDeviceOnly) throws {
        self.authState = authState
        self.config = config
        self.accessibility = accessibility

        super.init()

        KeycloakAuth.configuration = config
    }

public required convenience init?(coder aDecoder: NSCoder) {
        try? self.init(authState:     aDecoder.decodeObject(forKey: "authState")     as! OIDAuthState,
                       config:        aDecoder.decodeObject(forKey: "config")        as! [String: String],
                       accessibility: aDecoder.decodeObject(forKey: "accessibility") as! CFString)
    }

我在 public required... 行收到错误 'self' used before 'self.init' call，在 try? self.init(... 行又收到同样的错误。

我查看了 Stack Overflow 上的其他一些相关问题。即这些：

所以我相应地安排了我的便利初始化来尝试 return 如果有任何问题则为零：

public required convenience init?(coder aDecoder: NSCoder) {
        guard
            let authState     = aDecoder.decodeObject(forKey: "authState")     as? OIDAuthState,
            let config        = aDecoder.decodeObject(forKey: "config")        as? [String: String]
        else {
            print("KeycloakTokenManager: There was an error intializing authState or config")
            return nil
        }

        let accessibility = aDecoder.decodeObject(forKey: "accessibility") as! CFString

        try? self.init(authState: authState, config: config, accessibility: accessibility)
    }

但我在同一代码（初始化程序和调用 self.init）上遇到了相同的错误。有趣的是，我的项目在 Swift 4 上构建良好，但我没有听说这是一个错误 Swift 5。我怎样才能摆脱这个错误？

Answer 1

一个解决方案是不调用指定的初始化器

public required init?(coder aDecoder: NSCoder) {
    guard
        let authState     = aDecoder.decodeObject(forKey: "authState")     as? OIDAuthState,
        let config        = aDecoder.decodeObject(forKey: "config")        as? [String: String]
    else {
        print("KeycloakTokenManager: There was an error intializing authState or config")
        return nil
    }

    self.authState = authState
    self.config = config 
    self.accessibility =  aDecoder.decodeObject(forKey: "accessibility") as! CFString

    super.init()

    KeycloakAuth.configuration = config
}

Answer 2

这是我刚刚发现的另一种解决方案，它也有效。因为初始化不抛出，所以最终的代码可以是这样的：

public init(authState: OIDAuthState, config: [String: String], accessibility: CFString = kSecAttrAccessibleWhenUnlockedThisDeviceOnly) {
    self.authState = authState
    self.config = config
    self.accessibility = accessibility

    super.init()

    KeycloakAuth.configuration = config
}

public required convenience init?(coder aDecoder: NSCoder) {
    self.init(authState:     aDecoder.decodeObject(forKey: "authState")     as! OIDAuthState,
              config:        aDecoder.decodeObject(forKey: "config")        as! [String: String],
              accessibility: aDecoder.decodeObject(forKey: "accessibility") as! CFString)
}

Swift 5: 'self' 在 'self.init' 调用之前使用

Swift 5: 'self' used before 'self.init' call

initialization

swift

swift5