解析字典行为奇怪
Parse dictionary behaviour strange
如果一个 key 值为 null 且另一个键不为空，则解析字典值。
来自 source 的值如果 id 的值为 null，则名称键无法解析。如果 id 的值不是 null 那么它的 return 就是 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]"
}
]
}
模型类
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
}
}
里面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"]
它仅在 id 持有一些字符串值时打印 else source.name return nil
谁能告诉我为什么会这样？
我是第一次使用 swift 语言。 :(
对于 Decodable 你必须添加伞形结构并且你必须在 Headline 中声明 author 并且在 Source 中声明 id 为可选，因为它们可以是 null。所有的CodingKey都合成了。
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
}
}
日期解码策略必须是 .iso8601 而不是 .secondsSince1970。
此代码将 articles 数组分配给数据源并在主线程上重新加载 table 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中写入
let headline = headlines[indexPath.row]
cell.lbl_NewsTitle?.text = headline.title
cell.lbl_NewsSource?.text = headline.source.name
如果一个 key 值为 null 且另一个键不为空，则解析字典值。
来自 source 的值如果 id 的值为 null，则名称键无法解析。如果 id 的值不是 null 那么它的 return 就是 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]"
}
]
}
模型类
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
}
}
里面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"]
它仅在 id 持有一些字符串值时打印 else source.name return nil
谁能告诉我为什么会这样？ 我是第一次使用 swift 语言。 :(
对于 Decodable 你必须添加伞形结构并且你必须在 Headline 中声明 author 并且在 Source 中声明 id 为可选，因为它们可以是 null。所有的CodingKey都合成了。
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
}
}
日期解码策略必须是 .iso8601 而不是 .secondsSince1970。
此代码将 articles 数组分配给数据源并在主线程上重新加载 table 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中写入
let headline = headlines[indexPath.row]
cell.lbl_NewsTitle?.text = headline.title
cell.lbl_NewsSource?.text = headline.source.name