当JSON使用数组对Swift对象进行编码时，出现异常“Invalid type in JSON write (__SwiftValue)”
当JSON使用数组对Swift对象进行编码时，出现异常“Invalid type in JSON write (__SwiftValue)”
提问于 2019-12-02 10:16:10
尝试将此Swift对象编码为JSON时获取异常*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid type in JSON write (__SwiftValue)'。所有非可选成员，对象可编码。什么是正确的编码方式，或者应该使用一些第三方库？
struct MediaItem: Codable {
var key: String = ""
var filename: String = ""
}
struct NoteTask: Codable {
var id: String = ""
var notes: String = ""
var mediaList: [MediaItem] = []
}
static func addTask(task: NoteTask, callback: @escaping TaskAPICallback) {
let configuration = URLSessionConfiguration.default
let session = URLSession(configuration: configuration)
let url = URL(string: postUrl)
var request : URLRequest = URLRequest(url: url!)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
let params: [String: Codable?] = [
"email": task.id,
"notes": task.notes,
"fileList": task.fileList
]
do {
request.httpBody = try JSONSerialization.data(withJSONObject: params, options: [])
} catch {
DispatchQueue.main.async {
callback(false)
}
return
}
...
}回答 1
Stack Overflow用户
发布于 2019-12-02 12:56:10
问题是您使用的是JSONSerialization而不是JSONEncoder。JSONSerialization是一种更老的基础/Objective-C写对象方式。它仅适用于基础对象(有关完整列表，请参阅documentation )。
相反，您应该使用JSONEncoder。棘手的部分是，如果您不做一些工作，JSONEncoder就不能直接编码Dictionary。有几种方法可以解决这个问题，但是如果这是您唯一要使用的JSON格式，我可能只需要使用CodingKeys为您的结构创建自定义键。
struct MediaItem: Codable {
var key: String = ""
var filename: String = ""
}
struct NoteTask: Codable {
var id: String = ""
var notes: String = ""
var mediaList: [MediaItem] = []
enum CodingKeys: String, CodingKey {
case id = "email"
case notes = "notes"
case mediaList = "fileList"
}
}
static func addTask(task: NoteTask, callback: @escaping TaskAPICallback) {
let configuration = URLSessionConfiguration.default
let session = URLSession(configuration: configuration)
let url = URL(string: postUrl)
var request : URLRequest = URLRequest(url: url!)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
do {
request.httpBody = try JSONEncoder().encode(task)
} catch {
DispatchQueue.main.async {
callback(false)
}
return
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/59131842
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