嵌套对象swift4可编码解码

Question

API发送给我这个json：

{
"name": "John Doe",
"details": [{
    "name": "exampleString"
}, {
    "name": [1, 2, 3]
}]

}

这里的问题是，details数组有两个不同值类型的字典。如何使用swift4的可解码协议在模型中解码这个json？

Answer 1

我不建议您使用异构类型来构造您的JSOn；在这种情况下，details.name可以是字符串，也可以是Int数组。虽然您可以这样做，但它很混乱，因为默认情况下它是一种静态类型的语言。如果您不能在这里将JSON更改为更干净的东西，那么一个游乐场展示了您如何选择使用Any进行动态行为。

//: Playground - noun: a place where people can play
import PlaygroundSupport
import UIKit

let json = """
{
"name": "John Doe",
"details": [{
"name": "exampleString"
}, {
"name": [1, 2, 3]
}]
}
"""


struct Detail {
    var name: Any?
    var nameString: String? {
        return name as? String
    }
    var nameIntArray: [Int]? {
        return name as? [Int]
    }
    enum CodingKeys: CodingKey {
        case name
    }
}

extension Detail: Encodable {
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        if let string = name as? String {
            try container.encode(string, forKey: .name)
        }
        if let array = name as? [Int] {
            try container.encode(array, forKey: .name)
        }
    }
}


extension Detail: Decodable {
    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        if let string = try? values.decode(String.self, forKey: .name) {
            name = string
        } else if let array = try? values.decode(Array<Int>.self, forKey: .name) {
            name = array
        }
    }
}

struct Record: Codable {
    var name: String
    var details: [Detail]
}

let jsonDecoder = JSONDecoder()
let record = try! jsonDecoder.decode(Record.self, from: json.data(using: .utf8)!)
print("\(record.details.first!.name!) is of type: \(type(of:record.details.first!.name!))")
print("\(record.details.last!.name!) is of type: \(type(of:record.details.last!.name!))")

产出如下：

exampleString is of type: String
[1, 2, 3] is of type: Array<Int>