如何从SwiftyJSON创建对象
我有一个代码,解析JSON的问题列表,我可以得到每个属性。如何遍历整个文件并为每个问题创建一个对象如何从SwiftyJSON创建对象,swift,swifty-json,Swift,Swifty Json,我有一个代码,解析JSON的问题列表,我可以得到每个属性。如何遍历整个文件并为每个问题创建一个对象 class ViewController: UIViewController { var hoge: JSON? override func viewDidLoad() { super.viewDidLoad() let number = arc4random_uniform(1000) let url = NSURL(string: "http://www.wire
class ViewController: UIViewController {
var hoge: JSON?
override func viewDidLoad() {
super.viewDidLoad()
let number = arc4random_uniform(1000)
let url = NSURL(string: "http://www.wirehead.ru/try-en.json?\(number)")
var request = NSURLRequest(URL: url!)
var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
if data != nil {
hoge = JSON(data: data!)
let level = hoge!["pack1"][0]["level"].intValue
let questionText = hoge!["pack1"][0]["questionText"].stringValue
let answer1 = hoge!["pack1"][0]["answer1"].stringValue
let answer2 = hoge!["pack1"][0]["answer2"].stringValue
let answer3 = hoge!["pack1"][0]["answer3"].stringValue
let answer4 = hoge!["pack1"][0]["answer4"].stringValue
let correctAnswer = hoge!["pack1"][0]["correctAnswer"].stringValue
let haveAnswered = hoge!["pack1"][0]["haveAnswered"].boolValue
}
}
}
我想在下面创建哪些对象的问题模型
class Question {
var level : Int?
var questionText : String?
var answer1 : String?
var answer2 : String?
var answer3 : String?
var answer4 : String?
var correctAnswer : String?
var haveAnswered : Bool = false
init(level: Int, questionText:String, answer1:String, answer2:String, answer3:String, answer4:String, correctAnswer: String, haveAnswered:Bool) {
self.level = level
self.questionText = questionText
self.answer1 = answer1
self.answer2 = answer2
self.answer3 = answer3
self.answer4 = answer4
self.correctAnswer = correctAnswer
self.haveAnswered = false
}
}
这就是我处理这个问题的方法 第一步 由于您的
init
内部Question
确实接收到非可选
对象,我觉得问题的属性也应该是非可选的。我还将属性从var
转换为let
(如果我错了,请告诉我)
步骤2
这是重构的问题
类。如您所见,我添加了一个类方法build
,它接收一个JSON
(aSwiftyJSON
),并返回一个问题(如果JSON包含正确的数据),否则返回nil
现在,我无法使用可失败的初始值设定项来执行此操作
步骤3
现在让我们看看viewDidLoad
func viewDidLoad() {
super.viewDidLoad()
let number = arc4random_uniform(1000)
if let
url = NSURL(string: "http://www.wirehead.ru/try-en.json?\(number)"),
data = NSURLConnection.sendSynchronousRequest(NSURLRequest(URL: url), returningResponse: nil, error: nil) {
// line #a
let rootJSON = JSON(data: data)
// line #b
if let questions = (rootJSON["pack1"].array?.map { return Question.build($0) }) {
// now you have an array of optional questions [Question?]...
}
}
}
在第a行,我将从连接接收到的所有数据(转换为JSON
)放入rootJSON
)
b线发生了什么
我尝试访问“pack1”
中的数组
如果数组存在,我运行map方法。这将提取数组的每个单元格,我将能够在闭包中用$0
参数名引用它
在闭包中,我使用这个json块(应该表示一个问题)来构建一个question
实例
结果将是一组问题?
。如果某些子数据无效,则可能存在错误值。如果需要,我可以演示如何从此数组中删除nil
值
我无法用真实数据尝试代码,希望这能有所帮助
for (item, content) in hoge {
let level = content["level"].intValue
}
这应该会起作用步骤1。我们将创建一个协议,其中包含一个构造函数方法和模型类
protocol JSONable {
init?(parameter: JSON)
}
class Style: JSONable {
let ID :String!
let name :String!
required init(parameter: JSON) {
ID = parameter["id"].stringValue
name = parameter["name"].stringValue
}
/* JSON response format
{
"status": true,
"message": "",
"data": [
{
"id": 1,
"name": "Style 1"
},
{
"id": 2,
"name": "Style 2"
},
{
"id": 3,
"name": "Style 3"
}
]
}
*/
}
第二步。我们将创建JSON的扩展,该扩展将JSON转换为模型类类型对象
extension JSON {
func to<T>(type: T?) -> Any? {
if let baseObj = type as? JSONable.Type {
if self.type == .array {
var arrObject: [Any] = []
for obj in self.arrayValue {
let object = baseObj.init(parameter: obj)
arrObject.append(object!)
}
return arrObject
} else {
let object = baseObj.init(parameter: self)
return object!
}
}
return nil
}
}
我希望这将是有用的
有关这方面的更多信息,请参阅此链接。
您可以使用专门为此目的设计的SwiftyJSONModel。因此,在您的情况下,模型如下所示:
class Question: JSONObjectInitializable {
enum PropertyKey: String {
case level, questionText
case answer1, answer2, answer3, answer4
case correctAnswer, haveAnswered
}
var level : Int?
var questionText : String?
var answer1 : String?
var answer2 : String?
var answer3 : String?
var answer4 : String?
var correctAnswer : String?
var haveAnswered : Bool = false
required init(object: JSONObject<PropertyKey>) throws {
level = object.value(for: .level)
questionText = object.value(for: .questionText)
answer1 = object.value(for: .answer1)
answer2 = object.value(for: .answer2)
answer3 = object.value(for: .answer3)
answer4 = object.value(for: .answer4)
correctAnswer = object.value(for: .correctAnswer)
haveAnswered = object.value(for: .haveAnswered) ?? false
}
}
let rootJSON = JSON(data: data)
let questions = rootJSON.arrayValue.flatMap { try? Question(json: $0) }
该框架为您提供了几个不错的功能:
所有密钥都存储在单独的enumPropertyKey
没有类似于stringValue
,intValue
等的样板文件
若JSON
无效,框架将给出一个详细的错误,您将立即看到到底出了什么问题
我看到您正在将您的属性(除了haveresponse
)声明为可选的。另一方面,init
的所有参数都是非可选的
。哪一个是正确的?回答得很好。我正在为一个类似的类建模,这确实帮助了我。@damianesteban谢谢。这是一个解决方案,在过去的一年里我改进了好几次。非常感谢!不幸的是,我得到了错误的json。我检查了JSON,它通过了验证。你能看看有什么问题吗?数据在原始JSON中,级别值是一个字符串
。因此,我们无法直接将其作为Int
检索。我将更新我的答案;-)同样的结果,糟糕的json:(这个答案非常好。我没有这样做就导致了内存泄漏,而这实际上是唯一帮助我的解决方案!谢谢!
Alamofire.request(.GET, url).validate().responseJSON { response in
switch response.result {
case .success(let value):
let json = JSON(value)
var styles: [Style] = []
if let styleArr = json["data"].to(type: Style.self) {
styles = styleArr as! [Style]
}
print("styles: \(styles)")
case .failure(let error):
print(error)
}
}
class Question: JSONObjectInitializable {
enum PropertyKey: String {
case level, questionText
case answer1, answer2, answer3, answer4
case correctAnswer, haveAnswered
}
var level : Int?
var questionText : String?
var answer1 : String?
var answer2 : String?
var answer3 : String?
var answer4 : String?
var correctAnswer : String?
var haveAnswered : Bool = false
required init(object: JSONObject<PropertyKey>) throws {
level = object.value(for: .level)
questionText = object.value(for: .questionText)
answer1 = object.value(for: .answer1)
answer2 = object.value(for: .answer2)
answer3 = object.value(for: .answer3)
answer4 = object.value(for: .answer4)
correctAnswer = object.value(for: .correctAnswer)
haveAnswered = object.value(for: .haveAnswered) ?? false
}
}
let rootJSON = JSON(data: data)
let questions = rootJSON.arrayValue.flatMap { try? Question(json: $0) }