如果一个key值是null而另一个不是键，则解析字典值。
如果source的值为id，则无法解析名称键中的null的值。如果id的值不是null，则其返回name值。
{
"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
}
}
内部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)")
}
}
}
cellForRowAt内部
cell.lbl_NewsTitle?.text = headlines[indexPath.row].title
cell.lbl_NewsSource?.text = headlines[indexPath.row].source["name"]
仅在id保留一些字符串值时打印，否则source.name返回nil
有人可以提出这样的建议吗？ 我是第一次使用快速语言。 :(
答案 0 :(得分：1)
对于Decodable，您必须添加伞形结构，并且必须在author中将Headline和id中的Source声明为可选，因为它们可以null。所有的CodingKeys都是合成的。
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
}
}
日期解码策略必须为.secondsSince1970，而不是.iso8601。
此代码将articles数组分配给数据源，并在主线程上重新加载表视图
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)")
}
}
}
数据源数组必须声明为
var headlines = [Headline]()
在cellForRowAt中写
let headline = headlines[indexPath.row]
cell.lbl_NewsTitle?.text = headline.title
cell.lbl_NewsSource?.text = headline.source.name