Разбирать словарь поведение странно - PullRequest
Новая
       35

Разбирать словарь поведение странно

0 голосов
/ 14 февраля 2019

Анализировать значение словаря, если одно значение key равно null, а другое - это ключ, а не NULL.

Значение из source ключ имени не может проанализировать, если значение id равно null.Если значение id не null, то оно возвращает значение name. 

    {
    "status": "ok",
    "totalResults": 70,
    "articles": [
        {
            "source": {
                "id": null,
                "name": "Bloombergquint.com"
            },
            "author": "Aman Kapadia, Forum Bhatt",
            "title": "Infibeam Auditors Raise Questions On Loans To Vendors - BloombergQuint",
            "description": "Auditors to Infibeam Avenues raise questions about loans to vendors.",
            "url": "https://www.bloombergquint.com/business/infibeam-auditors-raise-questions-on-loans-to-vendors",
            "urlToImage": "https://images.assettype.com/bloombergquint%2F2018-02%2F11136839-3c0c-4356-b4d3-c918f4d417ad%2F323233043_1-9%20(1).jpg?rect=0%2C204%2C4000%2C2100&w=1200&auto=format%2Ccompress",
            "publishedAt": "2019-02-15T14:58:37Z",
            "content": "Auditors to Infibeam Avenues Ltd. raised questions about loans to vendors and how it recognises revenue in a fresh concern for the online retailer. SRBC & Co. LLP, the audit arm of EY, and Shah & Taparia sought more information to justify the rational… [+1985 chars]"
        },
        {
            "source": {
                "id": null,
                "name": "Moneycontrol.com"
            },
            "author": null,
            "title": "RBI lifts cap on FPI investments in corporate bonds - Moneycontrol.com",
            "description": "While the provision was aimed at incentivising FPIs to maintain a portfolio of assets, market feedback indicates that foreign portfolio investors (FPIs) have been constrained by this stipulation, the RBI said.",
            "url": "https://www.moneycontrol.com/news/business/rbi-lifts-cap-on-fpi-investments-in-corporate-bonds-3545571.html",
            "urlToImage": "https://static-news.moneycontrol.com/static-mcnews/2017/03/RBI-770x433.jpg",
            "publishedAt": "2019-02-15T13:26:00Z",
            "content": "The Reserve Bank of India (RBI) Friday withdrew the 20 per cent limit on investments by FPIs in corporate bonds of an entity with a view to encourage more foreign investments. As part of the review of the FPI investment in corporate debt undertaken in April 2… [+696 chars]"
        },
        {
            "source": {
                "id": null,
                "name": "Rushlane.com"
            },
            "author": "Rishabh Jain",
            "title": "2019 Honda Civic Review test drive - Still got the charm? - RushLane",
            "description": "Honda is back with the Civic in India. But does it have enough to attract those who love driving?",
            "url": "https://www.rushlane.com/2019-honda-civic-review-test-drive-12297473.html",
            "urlToImage": "https://www.rushlane.com/wp-content/uploads/2019/02/2019-honda-civic-review-test-drive-photos-specs-launch-price-14.jpg",
            "publishedAt": "2019-02-15T12:59:00Z",
            "content": "The Civic happens to be one of most loved brands from Honda in India. Globally too, it is one of those rare brands which have seen 10 proper generation changes. It is sold in multiple body types like Sedan, Coupe and Hatchback, however the Indian market only … [+8342 chars]"
        },
        {
            "source": {
                "id": null,
                "name": "Team-bhp.com"
            },
            "author": "Aditya Nadkarni",
            "title": "Maruti Swift, Dzire, Ertiga could get CNG variants - Team-BHP",
            "description": "According to a media report, Maruti Suzuki might introduce CNG variants of its cars in the years to come. The move could be taken in response to comply with the BS-VI emission norms, which are scheduled ...",
            "url": "https://www.team-bhp.com/news/maruti-swift-dzire-ertiga-could-get-cng-variants",
            "urlToImage": "https://www.team-bhp.com/sites/default/files/styles/large/public/1_639.jpg",
            "publishedAt": "2019-02-15T12:43:30Z",
            "content": "According to a media report, Maruti Suzuki might introduce CNG variants of its cars in the years to come. The move could be taken in response to comply with the BS-VI emission norms, which are scheduled to be implemented in 2020 and tighter fuel efficiency no… [+1119 chars]"
        }
   ]
}

ModelClass 

private struct Headline: Decodable {
    let author: String
    let title: String
    let source: Source

    struct Source: Codable {
        var id : String
        var name : String
    }

    private enum CodingKeys: String, CodingKey {

        case author
        case title
        case source
    }
}

Inside ViewController 

let url = ""
    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .secondsSince1970
    // It is necessary for correct decoding. Timestamp -> Date.

        Alamofire.request(url, method: .get, parameters: nil, encoding: JSONEncoding.default, headers: nil)
            .responseJSON { response in
                switch response.result {
                case .success:
//                    ??? how to assing here! access the value global????
                case .failure(let error):
                    print("Request failed with error: \(error)")
            }
        }
    }

Inside cellForRowAt

cell.lbl_NewsTitle?.text = headlines[indexPath.row].title
cell.lbl_NewsSource?.text = headlines[indexPath.row].source["name"]

Он печатается только когда id содержит некоторое строковое значение, иначе source.name возвращает nil

Может ли кто-нибудь посоветовать, почему это так?Я впервые использую быстрый язык.:(

1 Ответ

0 голосов
/ 16 февраля 2019

Для Decodable необходимо добавить структуру зонта и объявить author в Headline и id в Source как необязательные, поскольку они могут быть null.Все CodingKeys синтезированы. 

struct Response : Decodable {
    let status: String
    let totalResults: Int
    let articles: [Headline]
}

struct Headline: Decodable {
    let author: String?
    let title: String
    let source: Source
    let publishedAt : Date

    struct Source: Decodable {
        let id: String?
        let name: String
    }
}

Вместо .secondsSince1970 стратегия декодирования даты должна быть .iso8601.

Этот код присваивает массиву articles источнику данных и перезагружает представление таблицы в главном потоке 

let url = ""

    Alamofire.request(url).responseJSON { response in
        switch response.result {
        case .success:
            let decoder = JSONDecoder()
            decoder.dateDecodingStrategy = .iso8601
            do {
               let result = try decoder.decode(Response.self, from: response.data!)
               self.headlines = result.articles
               DispatchQueue.main.async {
                    self.tableView.reloadData()
               }
            } catch { print("Decoding error:", error) }
        case .failure(let error):
            print("Request failed with error: \(error)")
        }
    }
}

Массив источника данных должен быть объявлен как 

var headlines = [Headline]()

В cellForRowAt записать 

let headline = headlines[indexPath.row]
cell.lbl_NewsTitle?.text = headline.title
cell.lbl_NewsSource?.text = headline.source.name
...