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.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
}
}
}
我的问题模型我想在下面创建哪些对象
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
}
}
答案 0 :(得分：13)
这就是我解决问题的方法。
由于init内部Question确实收到non optional个对象，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（告诉我，如果我错了）。
这是重构的Question类。如您所见，我添加了一个类方法build，它接收JSON（a SwiftyJSON）并返回Question（如果json包含正确的数据），否则为nil。
目前我无法使用
执行此操作failable initializer。
extension String {
func toBool() -> Bool? {
switch self.lowercaseString {
case "true", "1", "yes" : return true
case "false", "0", "no" : return false
default: return nil
}
}
}
class Question {
let level: Int
let questionText: String
let answer1: String
let answer2: String
let answer3: String
let answer4: String
let correctAnswer: String
let haveAnswered: Bool
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
}
class func build(json:JSON) -> Question? {
if let
level = json["level"].string?.toInt(),
questionText = json["questionText"].string,
answer1 = json["answer1"].string,
answer2 = json["answer2"].string,
answer3 = json["answer3"].string,
answer4 = json["answer4"].string,
correctAnswer = json["correctAnswer"].string,
haveAnswered = json["haveAnswered"].string?.toBool() {
return Question(
level: level,
questionText: questionText,
answer1: answer1,
answer2: answer2,
answer3: answer3,
answer4: answer4,
correctAnswer: correctAnswer,
haveAnswered: haveAnswered)
} else {
debugPrintln("bad json \(json)")
return nil
}
}
}
现在让我们看一下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#a行，我在rootJSON内放入从连接收到的整个数据（转换为JSON）。
第#b行会发生什么？
我尝试访问位于"pack1"内的数组。
rootJSON["pack1"].array?
如果数组存在，我运行map方法。这将提取数组的每个单元格，我将能够在闭包内使用$0参数名称引用它。
在闭包内部，我使用这个json块（应该代表一个问题）来构建一个Question实例。
结果将是Question?的数组。如果某些儿子数据无效，可能会有不良值。如果您愿意，我可以向您展示如何从此数组中删除nil值
我无法使用真实数据尝试代码，希望这会有所帮助。
答案 1 :(得分：7)
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Model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"
}
]
}
*/
}
步骤2.我们将创建JSON的扩展，它将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
}
}
步骤3.将代码与Alamofire或其他代码一起使用。
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)
}
}
我希望这会有用。
有关此内容的更多信息，请参阅此链接 https://github.com/SwiftyJSON/SwiftyJSON/issues/714
答案 2 :(得分：7)
您可以使用专为此目的而设计的SwiftyJSONModel。所以在你的情况下，模型将是这样的：
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
}
}
然后这样做：
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：
PropertyKey stringValue，intValue等JSON无效，框架会发出详细错误，您会立即看到出现了什么问题答案 3 :(得分：1)
pywintypes27.dll
应该有效