给定这个模型:
public class RSS2Feed {
public var channel: RSS2FeedChannel?
public init() {}
}
public class RSS2FeedChannel {
public var title: String?
public var description: String?
public init() {}
}
我需要做什么才能获取属性名称和值RSS2FeedChannel
实例?
这就是我正在尝试的:
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
}
最终,我试图创建一个Dictionary
使用反射与实例匹配,但到目前为止我无法获取实例的属性名称和值。
文档说:
适当时可以使用可选标签,例如表示存储属性或活动枚举案例的名称,并将在字符串传递给后代方法时用于查找。
但我只得到一个“Some”字符串。
此外, value 属性返回一个带有 Type 的字符串RSS2FeedChannel
当我期望每个孩子都是“反射实例结构的元素。”!
当我理解正确时,这应该可以解决您的问题:
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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