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，其中包含 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...问题是，它表示 Photo 的属性DatabaseTableNames 结构体，需要声明为 fileprivate，因为 PhotoTable 是 private...

我在这里做错了什么？

Answer 1

关键是嵌套 PhotoTable 并使其属性静态化。

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

使用示例：

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

Answer 2

更换您的 private 设置 - 并确保它与您要使用的 UIViewController 在同一个文件中定义

private struct DatabaseTableNames {
    let Photo = PhotoTable()
}

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

然后，访问结构体

private var photo : DatabaseTableNames?