试图用奇怪的初始结构解码json
我有一个json代码结构的问题,我不能解码到swift。 文本中的树如下所示:试图用奇怪的初始结构解码json,json,swift,jsondecoder,Json,Swift,Jsondecoder,我有一个json代码结构的问题,我不能解码到swift。 文本中的树如下所示: { "features": [ { "geometry": { "coordinates": [ 21.9877132, 38.9953683 ], "type": "P
{
"features": [
{
"geometry": {
"coordinates": [
21.9877132,
38.9953683
],
"type": "Point"
},
"properties": {
"country": "Greece",
"countrycode": "GR",
"extent": [
19.2477876,
41.7488889,
29.7296986,
34.7006096
],
"name": "Greece",
"osm_id": 192307,
"osm_key": "place",
"osm_type": "R",
"osm_value": "country",
"type": "country"
},
"type": "Feature"
},strong text
我想知道坐标和国家代码。
我尝试了很多选择,但都没有成功,我把我的第一次尝试留在这里,虽然没有成功,但这是我第一次尝试的原因:
import Foundation
struct features: Codable {
let features: [Features]
}
struct Features: Codable {
let geometry: [Geometry]
let properties: [Properties]
}
struct Geometry: Codable {
let coordinates: [Double]
}
struct Properties: Codable {
let country, countrycode, name: String?
}
以及要解码的代码:
var coordinates = [features]()
let urlString = "https://photon.komoot.io/api/?q=Greece"
if let url = URL(string: urlString) {
if let data = try? Data(contentsOf: url) {
let decoder = JSONDecoder()
if let jsonCord = try? decoder.decode([features].self, from: data) {
coordinates = jsonCord
}
}
}
var coordinates: [Feature] = []
let urlString = "https://photon.komoot.io/api/?q=Greece"
if let url = URL(string: urlString) {
if let data = try? Data(contentsOf: url) {
let decoder = JSONDecoder()
if let jsonCord = try? decoder.decode(Features.self, from: data) {
coordinates = jsonCord.features
}
}
}
如果您能为我提供解决此问题的方法,我将不胜感激。您的数据模型应如下所示:
struct Features: Codable {
let features: [Feature]
}
struct Feature: Codable {
let geometry: Geometry
let properties: Properties
}
struct Geometry: Codable {
let coordinates: [Double]
}
struct Properties: Codable {
let country, countrycode, name: String?
}
以及要解码的代码:
var coordinates = [features]()
let urlString = "https://photon.komoot.io/api/?q=Greece"
if let url = URL(string: urlString) {
if let data = try? Data(contentsOf: url) {
let decoder = JSONDecoder()
if let jsonCord = try? decoder.decode([features].self, from: data) {
coordinates = jsonCord
}
}
}
var coordinates: [Feature] = []
let urlString = "https://photon.komoot.io/api/?q=Greece"
if let url = URL(string: urlString) {
if let data = try? Data(contentsOf: url) {
let decoder = JSONDecoder()
if let jsonCord = try? decoder.decode(Features.self, from: data) {
coordinates = jsonCord.features
}
}
}
这是一种特殊的JSON格式,称为GeoJSON 在iOS 13/macOS 15中,苹果在
MapKit
中引入了一个API来解码这种格式:
要获取坐标和国家代码,您只需要一个自定义结构
import MapKit
struct Country : Decodable {
let countrycode : String
}
let url = URL(string: "https://photon.komoot.io/api/?q=Greece")!
let task = URLSession.shared.dataTask(with: url) { data, _, error in
if let error = error { print(error); return }
do {
let result = try MKGeoJSONDecoder().decode(data!) as! [MKGeoJSONFeature]
if let feature = result.first,
let propertyData = feature.properties {
let country = try JSONDecoder().decode(Country.self, from: propertyData)
print(country.countrycode)
if let annotations = feature.geometry as? [MKPointAnnotation],
let coordinate = annotations.first?.coordinate {
print(coordinate)
}
}
} catch {
print(error)
}
}
task.resume()
解决这个问题的第一步是使用正确的错误处理,使用
try
和do/catch
而不是try?
并在catch子句中打印错误。谢谢,根对象(以及geometry
和properties
)显然是一个字典,而不是一个数组。(注意{}
)并请始终以大写字母开头命名结构。永远不要用同步的数据从远程URL加载数据(内容:
structs始终以大写开头,请检查。远程URL将不会被使用,只是这里有一个问题。是的,它们是一个字典,我不知道如何处理。感谢vadian花时间将字典变成一个结构(没有括号).正如Joakim编写的打印错误
,它会准确地告诉您出了什么问题。感谢vadian提供的额外信息,了解这些信息非常有用。