Swift - 如何声明私有嵌套结构？

Question

I want o make my code more readable, so I decided to make some repeated dictionary keys, soft coded... So I created a new .swift file, with 2 structs in it:

struct DatabaseTableNames {
    let Photo = PhotoTable()
}

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

So I have the initial struct I'm gonna use and the second one, which I don't want it to be visible outside of the file's scope... The thing is, it says that the Photo property of the DatabaseTableNames struct, needs to be declared as fileprivate since PhotoTable is private ...

What am I doing wrong here?

Answer 1

The key was to nest PhotoTable and make its properties static.

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

Example Use:

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

Answer 2

swap around your private settings - and make sure this is defined in the same file as the UIViewController you want to use it

private struct DatabaseTableNames {
    let Photo = PhotoTable()
}

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

and then, access the struct

private var photo : DatabaseTableNames?