swift 中字符串的对象列表

Question

我想将对象列表转换为字符串以调用我的 API?

它适用于 data 数组。但是 data2 数组

出现错误

错误 terminating with uncaught exception of type NSException

let data = ["123","1234"]

let data2 = [NotificationModel(version: "2", bigPicture: "data"),
                 NotificationModel(version: "3", bigPicture: "data")]

struct NotificationModel: Codable {
    var version : String?
    var bigPicture : String?
}

func json(from object:Any) -> String? {
    guard let data = try? JSONSerialization.data(withJSONObject: object, options: []) else {
        return nil
    }
    return String(data: data, encoding: String.Encoding.utf8)
}

    print("\(json(from:data2 as [NotificationModel]))")
    print("\(json(from: data as Any))")

结果应该是这样的

"notifications":"[{\"body\":\"dfg\",\"groupKey\":\"bhanukacom072\",\"messageData\":\"{\\"audioSeconds\\":0,\\"chatCount\\":891,\\"chatFieldId\\":\\"16184658508585169\\",\\"content\\":\\"dfg\\",\\"createdAt\\":{\\"_seconds\\":1621765164,\\"_nanoseconds\\":964804000},\\"fromUserId\\":\\"W6qfPNooEwhRU3xVlF3FZYdxGeZ2\\",\\"fromUserName\\":\\"bhanuka com 072\\",\\"isChat\\":true,\\"messageStatus\\":\\"U\\",\\"readStatus\\":\\"U\\",\\"requirementId\\":\\"671\\",\\"sendBy\\":\\"V\\",\\"timestamp\\":1621765164964,\\"toUserId\\":\\"TVhRuzRekqnPhhmb1oATXwc10En62\\",\\"toUserName\\":\\"bhanuka yc\\",\\"type\\":\\"text\\",\\"unReadMessageCount\\":4,\\"version\\":2,\\"docId\\":\\"eIfo9thTzyUmURMGX2uyj\\"}\",\"title\":\"You have a message from bhanuka com 072\",\"version\":\"2\"}]","isVendor":false},"executionTime":0.008731000125408173,"log":"Initial response","endpoint":"createChat"}

Answer 1

data 是一个简单的字符串数组，也是一个有效的 json 对象。但是 data2 是 Codable 的数组。默认情况下还不是有效的 json 对象。您需要首先将您的 data2: [NotificationModel] 转换为 data2Json: [[String:Any]] 以使其成为有效对象，然后将其传递给您的 json(from object 函数。您应该使用 JSONEncoder 将 [NotificationModel] 编码为有效的 json 对象。

Answer 2

您需要确保您尝试编码的内容符合 Encodable 协议。您可以使用 Foundation 的 JSONEncoder 加上一点泛型来确保 json 函数的输入是可编码的，如下所示：

import Foundation

let data = ["123","1234"]

let data2 = [NotificationModel(version: "2", bigPicture: "data"),
                 NotificationModel(version: "3", bigPicture: "data")]

struct NotificationModel: Codable {
    var version : String?
    var bigPicture : String?
}

func json<T:Encodable>(from object:T) -> String? {
    let encoder = JSONEncoder()
        
    do {
        let data = try encoder.encode(object)
        return String(data: data, encoding: .utf8)
    } catch {
        return nil
    }
}

print("\(json(from: data2))")
print("\(json(from: data))")

swift 中字符串的对象列表

List of object to string in swift

ios

swift

swift5