如何在Swift中将多个值与枚举关联？

Question

I'm trying to use an enum to categorize the various sections in a UITableView .

Here's the current implementation of the Section enum :

enum Section: Int, CustomStringConvertible {

    case open = 0
    case closed = 1

    var description: String {
        switch self {
        case .open:
            return "Open"
        case .closed:
            return "Closed"
        }
    }
}

Here's how I'm using it to name the titles for the headers in my UITableView sections :

override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return Section(rawValue: section)?.description
}

I'm just curious to know if there's a better way of implementing this. Perhaps with tuples. I'm not exactly sure, but I'd love to see if there's a better solution.

This is just one use case and the two cases given are just for brevity. I'd like to use multiple values, for instance UIColors associated with the given case .

Answer 1

If all you're trying to do is set up a correspondence between numbers and strings:

0 -> Open
1 -> Closed

... then it's hard to see what the enum is for. What you want is a dictionary where the numbers are keys, or even just a simple array :

let arr = ["Open", "Closed"]

In the array, the string is indexed by the numbers:

return arr[rawValue: section]

Answer 2

If you are going to use the enum to provide other information for the header (eg. background color, or whatever) you could add more vars to the enum as you did with the description.

But if you are only using for header titles you are probably better with an array:

let sectionTitles = ["Open", "Closed"] //var if the section can change.

override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    return sectionTitles[section]
}

Answer 3

Assuming you will be adding more variables or functionality to this enum, your syntax is fine. You can consolidate a bit when naming the cases like this:

case open, closed, thirdCase, fourthCase

If your enum has a rawValue of Int, and the cases start from 0 and number incrementally, you don't have to assign the values.

If you wanted the increments to start at a different number than 0, you can set it up like so:

case open = 3, closed, thirdCase, fourthCase

Your cases would then have a rawValues of 3, 4, 5, 6