Swift - 如何声明私有嵌套结构？

Question

我想让我的代码更具可读性，所以我决定制作一些重复的字典键，软编码...所以我创建了一个新的.swift文件，里面有2个结构：

struct DatabaseTableNames {
    let Photo = PhotoTable()
}

private struct PhotoTable {
    let lowQuality = "lowQuality"
    let highQuality = "highQuality"
    let numberOfLikes = "numberOfLikes"
}

所以我有我要使用的初始结构和第二个结构，我不希望它在文件范围之外可见......事情是，它说， DatabaseTableNames结构的Photo属性，需要要声明为fileprivate因为PhotoTable是private ......

我在这做错了什么？

Answer 1

关键是嵌套PhotoTable并使其属性保持静态。

struct DatabaseTableNames {
    struct PhotoTable {
        static let lowQuality = "lowQuality"
        static let highQuality = "highQuality"
        static let numberOfLikes = "numberOfLikes"
    }
}

示例使用：

let test = DatabaseTableNames.PhotoTable.lowQuality
print(test)

Answer 2

交换您的private设置 - 并确保在与您要使用它的UIViewController相同的文件中定义它

private struct DatabaseTableNames {
    let Photo = PhotoTable()
}

struct PhotoTable {
    let lowQuality = "lowQuality"
    let highQuality = "highQuality"
    let numberOfLikes = "numberOfLikes"
}

然后，访问结构

private var photo : DatabaseTableNames?