Swift 的问题是有一种方法可以让枚举类型具有一个可以具有关联值的情况。
我有一个 API 可以为我提供可用的过滤器,该 API 不太可能但有可能添加其他过滤器类型。因此,如果 API 发送未知的过滤器类型,我希望将该信息与枚举相关联。
以下是我对此的不同想法。
我的前两次尝试没有编译。我的第三次尝试感觉有点笨拙。
有没有人有更好的方法来做到这一点?您认为我不应该使用枚举来解决这个问题吗?
typealias APIFilterIdentifier = String
/* Does Not Compile */
enum EnumTestAssociatedValeu: APIFilterIdentifier {
case Unknown(APIFilterIdentifier)
case Everyone = "everyone"
case Team = "myteam"
}
/* Does not compile */
enum EnumTestDefaultAssociatedValues: APIFilterIdentifier {
case Unknown(APIFilterIdentifier)
case Everyone(APIFilterIdentifier = "everyone")
case Team(APIFilterIdentifier = "myteam")
}
/* Compiles but is there a better way? */
enum EnumTestWithCustomInit {
case Unknown(APIFilterIdentifier)
case Everyone
case Team
init(filterIdentifier: APIFilterIdentifier) {
let everyone: APIFilterIdentifier = EnumTestWithCustomInit.everyoneFilterIdentifier
let team: APIFilterIdentifier = EnumTestWithCustomInit.teamFilterIdentifier
switch filterIdentifier {
case everyone:
self = .Everyone
case team:
self = .Team
default:
self = .Unknown(filterIdentifier)
}
}
func asIdentifer() -> APIFilterIdentifier {
switch self {
case .Everyone:
return EnumTestWithCustomInit.everyoneFilterIdentifier
case .Team:
return EnumTestWithCustomInit.teamFilterIdentifier
case .Unknown(let filterIdentifier):
return filterIdentifier
}
}
private static var everyoneFilterIdentifier: APIFilterIdentifier {
return "everyone"
}
private static var teamFilterIdentifier: APIFilterIdentifier {
return "myteam"
}
}
我知道这有点旧了,但这能满足您的需求吗?
typealias FilterIdentifier = String
enum DefaultAPIFilters: FilterIdentifier {
case Everyone = "everyone"
case Team = "team"
}
enum APIFilters {
case Default(DefaultAPIFilters)
case Custom(FilterIdentifier)
}
let everyoneFilter = APIFilters.Default(.Everyone)
let teamFilter = APIFilters.Default(.Team)
let clownFilter = APIFilters.Custom("clowns_only")
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