Question

我遇到了编译错误，我在解释时遇到了问题。预期的参数类型看起来与我传递给它的相同，所以我不确定该怎么做。可能最好只是粘贴错误和相关的代码位。

这里失败了：

static func DefaultProvider() -> ReactiveManabiAPIProvider<ManabiAPI> {
    return ReactiveManabiAPIProvider(endpointClosure: endpointsClosure,
        requestClosure: endpointResolver(),
        stubClosure: StubBehaviour,
        plugins: APIProvider.plugins)
}

错误信息：

错误：无法转换类型＆＃39;（ManabiAPI）的值 - ＆gt;端点＆＃39;预期参数类型＆＃39; _ - ＆gt;端点＆LT; _＆GT;＆＃39; 返回ReactiveManabiAPIProvider（endpointClosure：endpointsClosure， ^ ~~~~~~~~~~~~~~~

以上引用的其他一些相关代码：

enum ManabiAPI {
[...]
}

extension ManabiAPI : TargetType {
    var baseURL: NSURL { return NSURL(string: "[...]")! }    
    var path: String {
    [...]
    }
    var parameters: [String: AnyObject]? {
    [...]
    }
    var method: ReactiveMoya.Method {
    [...]
    }
    [...]
}

public class ReactiveManabiAPIProvider<Target where Target: TargetType> : ReactiveCocoaMoyaProvider<Target> {
    var appController: AppController
    var requestErrors: RACSubject

    override init(endpointClosure: MoyaProvider<Target>.EndpointClosure = MoyaProvider.DefaultEndpointMapping,
        requestClosure: MoyaProvider<Target>.RequestClosure = MoyaProvider.DefaultRequestMapping,
        stubClosure: MoyaProvider<Target>.StubClosure = MoyaProvider.NeverStub,
        manager: Manager = Alamofire.Manager.sharedInstance,
        plugins: [PluginType] = [], stubScheduler: DateSchedulerType? = nil) {
            let appDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
            appController = appDelegate.appController!

            requestErrors = RACSubject()

            super.init(endpointClosure: endpointClosure, requestClosure: requestClosure, stubClosure: stubClosure, manager: manager, plugins: plugins)
    }
    [...]
}

如果能看到其他任何内容，请告诉我。

Answer 1

我很难在操场上尝试这个解决方案，因为上面的例子仍然有点太小。但我怀疑您需要在函数Target的return子句中的TargetType初始化程序中明确声明泛型ReactiveManabiAPIProvider类型（在类型约束DefaultProvider()下）。 E.g：

static func DefaultProvider() -> ReactiveManabiAPIProvider<ManabiAPI> {
    return ReactiveManabiAPIProvider<ManabiAPI>(endpointClosure: endpointsClosure,
        requestClosure: endpointResolver(),
        stubClosure: StubBehaviour,
        plugins: APIProvider.plugins)
}

否则返回初始化ReactiveManabiAPIProvider而没有关联的泛型，并且自然后面的返回强制转换失败，因为函数返回期望ReactiveManabiAPIProvider实例具有泛型Target类型ManabiAPI。

Answer 2

这就是我遇到完全相同问题的代码（我使用的是Moya 6.5.0）

public protocol ApiService {
    var apiProvider: ReactiveCocoaMoyaProvider<ApiRouter> { get }
    func request(token: ApiRouter) -> SignalProducer<Response, NSError>
}

public class ApiServiceImpl: ApiService {
    private let application: UIApplication
    public var apiProvider: ReactiveCocoaMoyaProvider<ApiRouter>

    public init(stubbing: Bool, application: UIApplication) {
        self.application = application
        if stubbing == false {
            let endpointsClosure = { (target: ApiRouter) -> Endpoint<ApiRouter> in
                return Endpoint<ApiRouter>(
                    URL: ApiServiceImpl.url(target),
                    sampleResponseClosure: { .NetworkResponse(200, target.sampleData) },
                    method: target.method,
                    parameters: target.parameters
                )
            }
            let networkActivityPlugin = NetworkActivityPlugin { type in
                switch type {
                case .Began : application.networkActivityIndicatorVisible = true
                case .Ended : application.networkActivityIndicatorVisible = false
                }
            }

            let networkLoggerPlugin = NetworkLoggerPlugin(verbose: true, responseDataFormatter: JSONResponseDataFormatter)
            let plugins = [networkActivityPlugin, networkLoggerPlugin]

            apiProvider = ReactiveCocoaMoyaProvider<ApiRouter>(endpointClosure: endpointsClosure, plugins: plugins)
        } else {
            apiProvider = ReactiveCocoaMoyaProvider<ApiRouter>(stubClosure: { _ in .Immediate })
        }
    }

    public func request(token: ApiRouter) -> SignalProducer<Response, NSError> {
        return apiProvider
            .request(token)
            .filterSuccessfulStatusAndRedirectCodes()
    }

    private static func url(route: TargetType) -> String {
        return route.baseURL.URLByAppendingPathComponent(route.path).absoluteString
    }
}

我通过将 [PluginType] 添加到插件数组定义行来修复该错误，因此它变为

let plugins: [PluginType] = [networkActivityPlugin, networkLoggerPlugin]

这个Swift类型错误意味着什么？它读起来就像预期的那样

2 个答案: