使用JSONDecoder后如何正确调用属性

Question

我正在解码一个JSON，然后我创建了一个completionHandler函数，以便能够在项目中的任何位置获得JSON解析的属性。但是，当我调用函数并只打印我想要的属性时，我将所有这些都放在一起，而不是调用的属性。

例如：我调用beer.name，所以当我打印出来时，我得到了解码的Struct中包含的所有属性和值。我做错了什么？我需要将这些值分开，以便能够填充UITableView和其他组件。

ViewController

override func viewDidLoad() {
super.viewDidLoad()
getApiData { (cerveja) in
for beer in cerveja {
print(beer.name!)
} 
}
}

这就是我在下面的电话中得到的：

[HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Buzz"), abv: 4.5, image_url: "https://images.punkapi.com/v2/keg.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Trashy Blonde"), abv: 4.1, image_url: "https://images.punkapi.com/v2/2.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Berliner Weisse With Yuzu - B-Sides"), abv: 4.2, image_url: "https://images.punkapi.com/v2/keg.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Pilsen Lager"), abv: 6.3, image_url: "https://images.punkapi.com/v2/4.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Avery Brown Dredge"), abv: 7.2, image_url: "https://images.punkapi.com/v2/5.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Electric India"), abv: 5.2, image_url: "https://images.punkapi.com/v2/6.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("AB:12"), abv: 11.2, image_url: "https://images.punkapi.com/v2/7.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Fake Lager"), abv: 4.7, image_url: "https://images.punkapi.com/v2/8.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("AB:07"), abv: 12.5, image_url: "https://images.punkapi.com/v2/9.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Bramling X"), abv: 7.5, image_url: "https://images.punkapi.com/v2/10.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Misspent Youth"), abv: 7.3, image_url: "https://images.punkapi.com/v2/keg.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Arcade Nation"), abv: 5.3, image_url: "https://images.punkapi.com/v2/12.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Movember"), abv: 4.5, image_url: "https://images.punkapi.com/v2/13.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Alpha Dog"), abv: 4.5, image_url: "https://images.punkapi.com/v2/14.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Mixtape 8"), abv: 14.5, image_url: "https://images.punkapi.com/v2/15.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Libertine Porter"), abv: 6.1, image_url: "https://images.punkapi.com/v2/16.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("AB:06"), abv: 11.2, image_url: "https://images.punkapi.com/v2/17.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Russian Doll – India Pale Ale"), abv: 6.0, image_url: "https://images.punkapi.com/v2/18.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Hello My Name Is Mette-Marit"), abv: 8.2, image_url: "https://images.punkapi.com/v2/19.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Rabiator"), abv: 10.27, image_url: "https://images.punkapi.com/v2/keg.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Vice Bier"), abv: 4.3, image_url: "https://images.punkapi.com/v2/keg.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Devine Rebel (w/ Mikkeller)"), abv: 12.5, image_url: "https://images.punkapi.com/v2/22.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Storm"), abv: 8.0, image_url: "https://images.punkapi.com/v2/23.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("The End Of History"), abv: 55.0, image_url: "https://images.punkapi.com/v2/24.png"), HakerRank___Bruno_Vavretchek.Cerveja(name: Optional("Bad Pixie"), abv: 4.7, image_url: "https://images.punkapi.com/v2/25.png")]

我确实需要的是所有的名字或abv或image_url的

模型文件夹：

struct Cerveja:Decodable{
let name:String?
let abv:Double
let image_url:String
}

网络文件夹：

func getApiData(completion: @escaping ([Cerveja]) -> ()){
guard let urlString = URL(string: "https://api.punkapi.com/v2/beers") else {
print("URL Error")
return
}
Alamofire.request(urlString).responseJSON { response in
if response.data == response.data{
do{
let decoder = try JSONDecoder().decode([Cerveja].self, from: response.data!)
print(decoder)
}catch{
print(error)
}
}else{print("API Response is Empty")}
}
}

Answer 1

实际上，您正在打印"解码器"。你必须这样写：

func getApiData(completion: @escaping ([Cerveja]) -> ()){
guard let urlString = URL(string: "https://api.punkapi.com/v2/beers") else {
print("URL Error")
return
}
Alamofire.request(urlString).responseJSON { response in
if let data = response.data{
do{
let decoder = try JSONDecoder().decode([Cerveja].self, from: data)
completion(decoder)
}catch{
print(error)
}
}else{print("API Response is Empty")}
}

}

避免强行展开。所以使用

if let data = response.data{ 
// Some code
}

然后你可以在viewDidLoad((中打印它

override func viewDidLoad() {
super.viewDidLoad()
getApiData { (cerveja) in
for beer in cerveja {
print(beer.name!)
} 
}
}

Answer 2

您当前附加的日志来自

print(decoder)

不是来自for循环，评论它并尝试，你甚至没有返回完成

func getApiData(completion: @escaping ([Cerveja]) -> ()){
guard let urlString = URL(string: "https://api.punkapi.com/v2/beers") else {
print("URL Error")
return
}
Alamofire.request(urlString).responseJSON { response in
if response.data == response.data{
do{
let decoder = try JSONDecoder().decode([Cerveja].self, from: response.data!)
// print(decoder)
completion(decoder) // here 
}
catch{
print(error)
}
}else{print("API Response is Empty")}
}
}

Answer 3

创建模型的数组>

var arrBeer: [Cerveja]()
override func viewDidLoad() {
super.viewDidLoad()
getApiData { (cerveja) in
arrBeer = cerveja // you save all your model objects in this array
}
}

现在可以使用控制器并在tableView单元格中使用了。

let model = arrBeer[indexPath.row]
cell.name = model.name

希望这对你有帮助。