Question

我有这样的数据模型

struct Aboutme {
    private(set) public var name: String

    init(name: String) {
        self.name = name
    }
}

像这样的数据服务

struct DataService {
    static let instance = DataService()

    private let sections = [
        [Aboutme(name: "Rate App on the App store")],
        [Aboutme(name: "Facebook")],
        [Aboutme(name: "Twitter")],
        [Aboutme(name: "Linkeden")],
        [Aboutme(name: "Instagram")],
        [Aboutme(name: "Email Feedback")]
                            ]

    func getSections() -> [Aboutme] {
        return sections
    }
}

然而，当我尝试返回关于我的类型的部分，它不会让我，说我不能将返回表达式转换为另一个。我怎样才能解决这个问题。

Answer 1

sections（隐式）声明为[[Aboutme]] getSections()的返回值为[Aboutme]，这是经典类型不匹配。

解决方案：

更改sections

的正文

struct DataService {
    static let instance = DataService()

    private let sections = [
        Aboutme(name: "Rate App on the App store"),
        Aboutme(name: "Facebook"),
        Aboutme(name: "Twitter"),
        Aboutme(name: "Linkeden"),
        Aboutme(name: "Instagram"),
        Aboutme(name: "Email Feedback")
                        ]

    func getSections() -> [Aboutme] {
        return sections
    }
}

更改getSections()

的返回类型

struct DataService {
    static let instance = DataService()

    private let sections = [
        [Aboutme(name: "Rate App on the App store")],
        [Aboutme(name: "Facebook")],
        [Aboutme(name: "Twitter")],
        [Aboutme(name: "Linkeden")],
        [Aboutme(name: "Instagram")],
        [Aboutme(name: "Email Feedback")]
                            ]

    func getSections() -> [[Aboutme]] {
        return sections
    }
}

因为sections是常量，函数getSections()是多余的，根本不需要。

为什么不简单

struct Aboutme {
    let name: String
}

您可以免费获得初始化程序，name是预期的常量。

Answer 2

您的sections跟随数组集合，因此您需要使用返回类型数组数组来返回所有[Aboutme]个对象。

func getSections() -> [[Aboutme]] {
    return sections
}

Answer 3

问题是getSections方法和变量sections的返回类型是不同的类型。您必须更改var sections类型，如getSections方法返回类型或getSections返回类型，如sections。

所以你可以这样做：

 struct DataService {
            static let instance = DataService()

            private let sections = [
                Aboutme(name: "Rate App on the App store"),
                Aboutme(name: "Facebook"),
                Aboutme(name: "Twitter"),
                Aboutme(name: "Linkeden"),
                Aboutme(name: "Instagram"),
                Aboutme(name: "Email Feedback")
        ]


            func getSections() -> [Aboutme] {
                return sections
            }
        }

或者像这样：

struct DataService {
            static let instance = DataService()

            private let sections = [
                [Aboutme(name: "Rate App on the App store")],
                [Aboutme(name: "Facebook")],
                [Aboutme(name: "Twitter")],
                [Aboutme(name: "Linkeden")],
                [Aboutme(name: "Instagram")],
                [Aboutme(name: "Email Feedback")]
        ]


            func getSections() -> [[Aboutme]] {
                return sections
            }
        }

Answer 4

你的部分声明是错误的。您将段声明为数组数组（类型为Array<Array<Section>>），因此当然不能将其转换为Array<Section>。

struct DataService {
    static let instance = DataService()

    private let sections = [
        Aboutme(name: "Rate App on the App store"),
        Aboutme(name: "Facebook"),
        Aboutme(name: "Twitter"),
        Aboutme(name: "Linkeden"),
        Aboutme(name: "Instagram"),
        Aboutme(name: "Email Feedback")
                            ]

    func getSections() -> [Aboutme] {
        return sections
    }
}

无法将“Array <aboutme>”类型的返回表达式转换为返回类型“[关于我]”

4 个答案: