类型'ListViewController.Pokemon‘的值没有下标

Question

我想从PokeApi返回口袋妖怪名，但是我有一个错误:类型为'ListViewController.Pokemon‘的值没有下标。

这是我的密码：

import UIKit

class ListViewController: UIViewController {
    @IBOutlet weak var pokemon1: UILabel!
    @IBOutlet weak var pokemon2: UILabel!
    @IBOutlet weak var pokemon3: UILabel!
    @IBOutlet weak var pokemon4: UILabel!
    @IBOutlet weak var pokemon5: UILabel!
    
    let url = "https://pokeapi.co/api/v2/pokemon"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        fetchData(from: url)
    }
    
    
    
    func fetchData(from url: String) {
        let url = URL(string: url)
        let defaultSession = URLSession(configuration: .default)
        let dataTask = defaultSession.dataTask(with: url!) { (data: Data?, response: URLResponse?, error: Error?) in
            if(error != nil) {
                print(String(describing: error))
                return
            }
            
            var json: Pokemon
            
            do {
                json = try JSONDecoder().decode(Pokemon.self, from: data!)
                Swift.print(json)
                
                DispatchQueue.main.async {
//                    self.pokemon1.text = json[0].name
                    self.pokemon2.text = json[1].results.name
//                    self.pokemon3.text = json[0].results.name
//                    self.pokemon4.text = json[3].name
//                    self.pokemon5.text = json[4].name
                    //callback: fonction que j'appelle à la suite d'un évènement
                }
            } catch {
                print(error)
                return
            }
        }
        dataTask.resume() // Commence la dataTask si elle n'est pas en marche actuellement
    }
    
    struct Pokemon: Codable {
        let results: [Result]
    }
    
    struct Result: Codable {
        let name: String
        let url: String
    }
}

我查看了打印结果，并收到了json数据。下面是印刷品中的内容：

Pokemon(results: [RattrapageIOS.ListViewController.Result(name: "bulbasaur", url: "https://pokeapi.co/api/v2/pokemon/1/"), RattrapageIOS.ListViewController.Result(name: "ivysaur", url: "https://pokeapi.co/api/v2/pokemon/2/"), RattrapageIOS.ListViewController.Result(name: "venusaur", url: "https://pokeapi.co/api/v2/pokemon/3/"), RattrapageIOS.ListViewController.Result(name: "charmander", url: "https://pokeapi.co/api/v2/pokemon/4/"), RattrapageIOS.ListViewController.Result(name: "charmeleon", url: "https://pokeapi.co/api/v2/pokemon/5/"), RattrapageIOS.ListViewController.Result(name: "charizard", url: "https://pokeapi.co/api/v2/pokemon/6/"), RattrapageIOS.ListViewController.Result(name: "squirtle", url: "https://pokeapi.co/api/v2/pokemon/7/"), RattrapageIOS.ListViewController.Result(name: "wartortle", url: "https://pokeapi.co/api/v2/pokemon/8/"), RattrapageIOS.ListViewController.Result(name: "blastoise", url: "https://pokeapi.co/api/v2/pokemon/9/"), RattrapageIOS.ListViewController.Result(name: "caterpie", url: "https://pokeapi.co/api/v2/pokemon/10/"), RattrapageIOS.ListViewController.Result(name: "metapod", url: "https://pokeapi.co/api/v2/pokemon/11/"), RattrapageIOS.ListViewController.Result(name: "butterfree", url: "https://pokeapi.co/api/v2/pokemon/12/"), RattrapageIOS.ListViewController.Result(name: "weedle", url: "https://pokeapi.co/api/v2/pokemon/13/"), RattrapageIOS.ListViewController.Result(name: "kakuna", url: "https://pokeapi.co/api/v2/pokemon/14/"), RattrapageIOS.ListViewController.Result(name: "beedrill", url: "https://pokeapi.co/api/v2/pokemon/15/"), RattrapageIOS.ListViewController.Result(name: "pidgey", url: "https://pokeapi.co/api/v2/pokemon/16/"), RattrapageIOS.ListViewController.Result(name: "pidgeotto", url: "https://pokeapi.co/api/v2/pokemon/17/"), RattrapageIOS.ListViewController.Result(name: "pidgeot", url: "https://pokeapi.co/api/v2/pokemon/18/"), RattrapageIOS.ListViewController.Result(name: "rattata", url: "https://pokeapi.co/api/v2/pokemon/19/"), RattrapageIOS.ListViewController.Result(name: "raticate", url: "https://pokeapi.co/api/v2/pokemon/20/")])

问题似乎是什么？

Answer 1

您正在尝试访问Pokemon类型并获取它的名称，但是name是Result类型的属性，其实例位于结果数组中。你想要的是：

json.results[0].name

若要获取数组中第一项的名称，请执行以下操作。如果您为您的类型使用了更多信息丰富的名称，那么问题就会更加明显。例如：

struct Wrapper: Codable {
        let results: [Pokemon]
    }
    
    struct Pokemon: Codable {
        let name: String
        let url: String
    }
}

然后你就需要

let wrapped = try JSONDecoder().decode(Wrapper.self, from: data!)
let pokemons = wrapped.results

//etc

self.pokemon2.text = pokemons[0].name