解析嵌套的 json 问题答案

【问题标题】：parsing nested json issue解析嵌套的 json 问题
【发布时间】：2018-12-18 05:29:35
【问题描述】：

我是新来的，我正在解析 json，它是侧数组中的数组，所以我不明白如何从 json 中获取数组，让我向你展示我的 json。

JSON

{
    "subject_list" =     (
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 4;
            "sub_list" =             (
                                {
                    "ch_id" = 17;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1530600693.jpg";
                    "ch_name" = " 01. Measurement";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 4;
                },
                                {
                    "ch_id" = 23;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1451930609.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 4;
                },
                                {
                    "ch_id" = 24;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1884777188.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 4;
                },
                                {
                    "ch_id" = 25;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1518702048.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 4;
                }
            );
            "sub_name" = Physics;
        },
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 8;
            "sub_list" =             (
                                {
                    "ch_id" = 26;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1437196139.jpg";
                    "ch_name" = " 1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 8;
                },
                                {
                    "ch_id" = 27;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1903171865.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 8;
                }
            );
            "sub_name" = Chemistry;
        },
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 9;
            "sub_list" =             (
                                {
                    "ch_id" = 31;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1319333294.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 9;
                }
            );
            "sub_name" = Testing;
        },
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 10;
            "sub_list" =             (
                                {
                    "ch_id" = 28;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1373218664.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 10;
                }
            );
            "sub_name" = "Test Subject";
        },
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 11;
            "sub_list" =             (
                                {
                    "ch_id" = 29;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/246189282.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 11;
                }
            );
            "sub_name" = "Test Subject 1";
        },
                {
            "con_id" = 2;
            "level_id" = 1;
            "sub_id" = 12;
            "sub_list" =             (
                                {
                    "ch_id" = 30;
                    "ch_image" = "http://mobileapp.xmeducation.com/upload/1342731807.jpg";
                    "ch_name" = "1. Test Chapter";
                    "con_id" = 2;
                    "level_id" = 1;
                    "sub_id" = 12;
                }
            );
            "sub_name" = "Test Subject 2";
        }
    );

这是我的 JSON，我想要来自 subject_list 的 sub_list 数组我已经完成了一些代码，让我给你看。

代码

func callSubChapAPI(){
        let preferences = UserDefaults.standard
        let studentlvl = "student_lvl"
        let student_lvl = preferences.object(forKey: studentlvl) as! String
        print(student_lvl)
        let params = ["level_id": student_lvl]
        Alamofire.request(subListWithChapter, method: .post, parameters: params).responseJSON(completionHandler: {(response) in
            switch response.result{
            case.success(let data):
                print(data)

                let json  = JSON(data)
                print(json)
                do {
                    let decoder = JSONDecoder()
                    decoder.keyDecodingStrategy = .convertFromSnakeCase
                    let subjects = try decoder.decode(SubjectResponse.self, from: data as! Data)
                    print(subjects)
                } catch {
                    print(error)
                }
            case.failure(let error):
                print(error.localizedDescription)
            }

        })
    }

这是我的结构：

struct sub_list {
    let ch_id : Int
    let ch_image: String
    let ch_name: String
    let con_id: String
    let level_id: String
    let sub_id: String
}

请查看我的代码和 json 格式请告诉我如何从 json 中获取 sub_list 数组，请见鬼，提前致谢。

【问题讨论】：

标签： json swift alamofire swifty-json

【解决方案1】：

实际上subject_list 也是一个array，所以你也需要对其进行迭代。

let data = json["subject_list"]
print(data)
data.array?.forEach({ (subject) in
     subject["sub_list"].array?.forEach({ (chapList) in
           let chapter = sub_list(ch_id: chapList["ch_id"].intValue, ch_image: chapList["ch_image"].stringValue, ch_name: chapList["ch_name"].stringValue, con_id: chapList["con_id"].stringValue, level_id: chapList["level_id"].stringValue, sub_id: chapList["sub_id"].stringValue)
           print(chapter)
           self.chapListData.append(chapter)
     })
})

self.collView.reloadData()

推荐

当您已经有 Apple 提供的 Codable 时，不值得为 json 解析添加任何依赖项。由于SwiftyJSON，它将减少您添加的大部分样板代码。

以下是您当前 api 的完整示例，

struct SubjectResponse: Decodable {
    let subjectList: [Subject]
}

struct Subject: Decodable {
    let subList: [Chapter]
}

struct Chapter: Decodable {
    let chId : Int
    let chImage: String
    let chName: String
    let conId: Int
    let levelId: Int
    let subId: Int
}

Alamofire.request(subListWithChapter, method: .post, parameters: params).responseData() { (response) in
    switch response.result {
    case .success(let data):
        do {
            let decoder = JSONDecoder()
            decoder.keyDecodingStrategy = .convertFromSnakeCase
            let subjects = try decoder.decode(SubjectResponse.self, from: data)
            print(subjects)
        } catch {
            print(error)
        }
    case .failure(let error):
        print(error.localizedDescription)
    }
}

【讨论】：

当我将您的代码放入数据时，它会给出这样的建议无法将“任何”类型的值转换为预期的参数类型“数据”，并且当我插入时！它给了我崩溃数据
错误类似于：无法将类型“__NSSingleEntryDictionaryI”（0x1c6c8dcc0）的值转换为“NSData”（0x1c6c8ddd8）。 2018-12-18 12:22:13.912859+0530 XMEducation[5496:1296891] 无法将“__NSSingleEntryDictionaryI”（0x1c6c8dcc0）类型的值转换为“NSData”（0x1c6c8ddd8）。
你必须使用.responseJSON，而你必须使用responseData()。复制完整的示例。
我复制了但仍然给我问题
你在这里使用了错误的方法Alamofire.request(subListWithChapter, method: .post, parameters: params).responseJSON。只需复制我上面提供的整个示例即可。