json - JSON 模型建议
问题描述
我必须创建一个好的模型来将从 JSON 接收到的数据传递给我的其他控制器。你们会怎么做呢?我需要在项目中的任何地方访问我的结构内的这些属性,以便能够填充 UI 组件等。
这是我的 API 响应文件:
import Foundation
import Alamofire
struct Description: Decodable {
let data: [data]
}
struct data: Decodable {
let id:Int?
let descricao:String?
let urlImagem:String?
}
func callApi(completion: @escaping (String, String) -> Void) {
guard let _url = URL(string: "https://alodjinha.herokuapp.com/categoria")else{return}
Alamofire.request(_url).responseJSON { (response) in
guard let info = response.data else{return}
do{
let dataParsed = try JSONDecoder().decode(Description.self, from: info)
for aData in dataParsed.data {
completion(aData.descricao!, aData.urlImagem!)
}
}catch{
print("Error serialization: \(error)")
}
}
}
这是我收到的 JSON 模型:
{
"data": [
{
"id": 1,
"descricao": "Games",
"urlImagem": "http:\/\/39ahd9aq5l9101brf3b8dq58.wpengine.netdna-cdn.com\/wp-content\/uploads\/2013\/06\/3D-Gaming.png"
},
{
"id": 2,
"descricao": "Livros",
"urlImagem": "http:\/\/4.bp.blogspot.com\/-6Bta1H9d22g\/UJAIJbqcHhI\/AAAAAAAAKi4\/hvgjWrlFc64\/s1600\/resenha-missiologia.png"
},
{
"id": 3,
"descricao": "Celulares",
"urlImagem": "http:\/\/pt.seaicons.com\/wp-content\/uploads\/2015\/11\/Mobile-Smartphone-icon.png"
},
{
"id": 4,
"descricao": "Inform\u00e1tica",
"urlImagem": "http:\/\/portal.ifrn.edu.br\/campus\/ceara-mirim\/noticias\/ifrn-oferece-curso-de-informatica-basica-para-pais-dos-estudantes\/image_preview"
},
{
"id": 5,
"descricao": "Eletrodom\u00e9stico",
"urlImagem": "http:\/\/classificados.folharegiao.com.br\/files\/classificados_categoria\/photo\/8\/sm_4d5ed3beb0f31b61cb9a01e46ecd0cf9.png"
},
{
"id": 6,
"descricao": "TVs",
"urlImagem": "http:\/\/i.utdstc.com\/icons\/256\/terrarium-tv-android.png"
},
{
"id": 7,
"descricao": "Filmes e S\u00e9ries",
"urlImagem": "https:\/\/pbs.twimg.com\/profile_images\/801033586438733824\/91Y_N91t_reasonably_small.jpg"
},
{
"id": 8,
"descricao": "M\u00f3veis e Decora\u00e7\u00f5es",
"urlImagem": "https:\/\/image.flaticon.com\/icons\/png\/128\/148\/148188.png"
},
{
"id": 9,
"descricao": "Moda, Beleza e Perfumaria",
"urlImagem": "http:\/\/icon-icons.com\/icons2\/196\/PNG\/128\/fashion_23852.png"
},
{
"id": 10,
"descricao": "Papelaria",
"urlImagem": "http:\/\/esen.pt\/in\/images\/stories\/skills_256.png"
}
]
}
非常感谢!
解决方案
1. 模型重构
首先,让我们为data
.
这样做是ImageData
因为类型名称应该是 Pascal Cased(这只是一个很好的编码约定)。例如ClassName
, StructName
, PascalCase
.
我们也不希望它被调用Data
,因为这会重载Foundation
's 的Data
类型。
所以我们的模型将是:
struct Description: Decodable {
let data: [ImageData]
}
struct ImageData: Decodable {
let id: Int
let descricao: String
let urlImagem: String
}
2.单身人士
我需要在项目中的任何地方访问我的结构中的这些属性
在这种情况下,我会使用一个引用图像数组的单例。
例子:
class SharedManager {
static let shared = SharedManager()
private init() {}
var images: [ImageData]?
}
3.服务助手
让我们编写一个名为的新类APIHelper
,它将充当服务助手。在这里,我们将有Alamofire
逻辑,所以让我们也改进一下。
- 让我们重命名
callApi(completion:)
为更有意义的东西,比如说,getImages(completion:)
- 为方便起见,让我们将其设为类方法。
- 也不是提供完成闭包
(String, String)
,而是让它提供[ImageData]?
;即ImageData
模型数组。- 以便稍后在应用程序中轻松访问
- 如果 url 无效或请求/解析失败,此数组是可选的(只是保持简单)
:
class APIHelper {
class func getImages(completion: @escaping ([ImageData]?)->Void) {
guard let url = URL(string: "https://alodjinha.herokuapp.com/categoria")
else {
completion(nil)
return
}
Alamofire
.request(url)
.responseJSON { (response) in
switch response.result {
case .success(_):
do {
let myImages = try JSONDecoder().decode(Description.self,
from: response.data!)
completion(myImages.data)
}
catch {
print(error)
completion(nil)
}
case .failure(let error):
print(error)
completion(nil)
}
}
}
}
4.在单例中设置数组
调用getImages(completion:)
一次设置SharedManager.shared.images
如下:
APIHelper.getImages { (imageData) in
print(imageData)
SharedManager.shared.images = imageData
}
5. 用法
现在您应该可以SharedManager.shared.images
随时随地访问图像数组(当然在您的应用范围内)
只是您的基本数组处理逻辑,但这里有几个示例:
遍历它们:
for imageData in SharedManager.shared.images ?? [] { print(imageData) }
访问特定索引处的图像
let imageIndex = 1 let imageURL = SharedManager.shared.images?[imageIndex].urlImagem print(imageURL)
查找具有特定 id 的图像:
let imageIDToFind = 7 let foundImage = SharedManager.shared.images?.first { $0.id == imageIDToFind } print(foundImage)
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