鉴于此模型:
public class RSS2Feed { public var channel: RSS2FeedChannel? public init() {} } public class RSS2FeedChannel { public var title: String? public var description: String? public init() {} }
为了获取RSS2FeedChannel实例的属性名称和值,我需要做什么?
这是我正在尝试的:
let Feed = RSS2Feed() Feed.channel = RSS2FeedChannel() Feed.channel?.title = "The Channel Title" let mirror = Mirror(reflecting: Feed.channel) mirror.children.first // ({Some "Some"},{{Some "The Channel Title... for (index,value) in mirror.children.enumerate() { index // 0 value.label // "Some" value.value // RSS2FeedChannel }
最后,我正在尝试创建一个匹配实例的Dictionary,使用反射,但到目前为止,我无法获取实例的属性名称和值.
文档说:
The optional label may be used when appropriate,e.g. to represent the name of a stored property or of an active enum case,and will be used for lookup when Strings are passed to the descendant method.
然而,我只得到一个“一些”字符串.
此外,当我希望每个子节点都是“反射实例结构的元素”时,value属性返回一个带有类型RSS2FeedChannel的字符串.
解决方法
当我理解正确这应该解决你的问题:
func aMethod() -> Void { let Feed = RSS2Feed() Feed.channel = RSS2FeedChannel() Feed.channel?.title = "The Channel Title" // Feed.channel?.description = "the description of your channel" guard let channel = Feed.channel else { return } let mirror = Mirror(reflecting: channel) for child in mirror.children { guard let key = child.label else { continue } let value = child.value guard let result = self.unwrap(value) else { continue } print("\(key): \(result)") } } private func unwrap(subject: Any) -> Any? { var value: Any? let mirrored = Mirror(reflecting:subject) if mirrored.displayStyle != .Optional { value = subject } else if let firstChild = mirrored.children.first { value = firstChild.value } return value }
只是swift 3的一些小变化:
private func unwrap(_ subject: Any) -> Any? { var value: Any? let mirrored = Mirror(reflecting:subject) if mirrored.displayStyle != .optional { value = subject } else if let firstChild = mirrored.children.first { value = firstChild.value } return value }
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