我正在学习有关使用 Swift 和 Codable 调用 REST API 的教程。尽管我在输入所有内容时都很小心,但我无法编译以下内容。谁能告诉我怎么了?另外,任何人都可以指出我更好的教程吗?错误是:
Catch block is unreachable
还有
cannot find json in scope
import UIKit
import Foundation
struct Example: Codable {
let userId: Int
let id: Int
let title: String
let completed: Bool
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
func getJson(completion: @escaping (Example)-> ()) {
let urlString = "https://jsonplaceholder.typicode.com/todos/1"
if let url = URL(string: urlString) {
URLSession.shared.dataTask(with: url) {data, res, err in
if let data = data {
let decoder = JSONDecoder()
do {
let json: Example = try! decoder.decode(Example.self, from: data)
completion(json)
}catch let error {
print(error.localizedDescription)
}
}
}.resume()
}
}
getJson() { (json) in
print(json.id)
}
}
最佳答案
struct Example: Decodable {
let userId: Int
let id: Int
let title: String
let completed: Bool
}
struct APIRequest {
var resourceURL: URL
let urlString = "https://jsonplaceholder.typicode.com/todos/1"
init() {
resourceURL = URL(string: urlString)!
}
//create method to get decode the json
func requestAPIInfo(completion: @escaping(Result<Example, Error>) -> Void) {
let dataTask = URLSession.shared.dataTask(with: resourceURL) { (data, response, error) in
guard error == nil else {
print (error!.localizedDescription)
print ("stuck in data task")
return
}
let decoder = JSONDecoder()
do {
let jsonData = try decoder.decode(Example.self, from: data!)
completion(.success(jsonData))
}
catch {
print ("an error in catch")
print (error)
}
}
dataTask.resume()
}
}
class ViewController: UIViewController {
let apiRequest = APIRequest()
override func viewDidLoad() {
super.viewDidLoad()
apiRequest.requestAPIInfo { (apiResult) in
print (apiResult)
}
}
}
关于使用 Codable 的 Swift Rest API 调用示例,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/65876500/