迅速反思2 [英] Reflection in swift 2

问题描述

我有一个班级用户:

import UIKit
import ObjectMapper


class User: NSObject, CustomStringConvertible, Mappable {

    var FirstName: NSString! ;
    var LastName: NSString! ;


    required init?(_ map: Map){

    }


    func mapping(map: Map) {

        FirstName <- map["FirstName"]
        LastName <- map["LastName"]

    }


    override var description:String {
        var s:String=""

  //USE REFLECTION TO GET NAME AND VALUE OF DATA MEMBERS      
        for var index=1; index<reflect(self).count; ++index {
            s += (reflect(self)[index].0 + ": "+reflect(self)[index].1.summary+"\t")
        }

        return s
    }
}

在swift 1.2中，我使用了reflect()方法来获取所有数据成员及其名称和值的数组.

In swift 1.2, I was using reflect() method to get array of all the data members with their names and values.

现在，我将其更新为swift 2后，出现以下错误:

Now, after I have updated to swift 2, I am getting the following error:

'reflect'不可用:调用'Mirror(reflecting :)'初始化程序

'reflect' is unavailable: call the 'Mirror(reflecting:)' initializer

通过一些试验，我能够通过以下方式获取数据成员的数量:Int(Mirror(reflecting: self).children.count)，但仍然无法获取成员名称及其值.

With some trials, I was able to get the count of data members by this: Int(Mirror(reflecting: self).children.count), but still, I am unable to get the member name and its value.

我研究了以下资源:

1. https://netguru.co/blog/reflection-swift
2. http://nshipster.com/mirrortype/

1. https://netguru.co/blog/reflection-swift
2. http://nshipster.com/mirrortype/

更新 我在这里找到了答案: https://stackoverflow.com/a/32846514/4959077 .但这并不能告诉我们如何找出反映价值的类型.如果值是int，并且我们将其解析为String，那么它将给出错误.

UPDATE I have found the an answer here: https://stackoverflow.com/a/32846514/4959077. But this doesn't tell how to find out the type of reflected value. If the value is int and we parse it into String then it gives error.

推荐答案

您可以按如下方式访问反映的属性标签"的名称，值和类型:

You may access the reflected attribute "label" name, value and type as follows:

let mirror = Mirror(reflecting: SomeObject)

var dictionary = [String: Any]() 
for child in mirror.children {
    guard let key = child.label else { continue }
    let value: Any = child.value

    dictionary[key] = value

    switch value {
    case is Int: print("integer = \(anyValue)")
    case is String: print("string = \(anyValue)")
    default: print("other type = \(anyValue)")
    }

    switch value {
    case let i as Int: print("• integer = \(i)")
    case let s as String: print("• string = \(s)")
    default: print("• other type = \(anyValue)")
    }

    if let i = value as? Int {
        print("•• integer = \(i)")
    }
}

注意:在每个问题的后续调查中，显示了三种确定反射值类型的方法.

Note: per the question followup, three approaches to determine the type of the reflected value are shown.

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