JSON 简介
JSON(JavaScript Object Notation, JS 对象简谱) 是一种轻量级的数据交换格式。它基于 ECMAScript (欧洲计算机协会制定的js规范)的一个子集，采用完全独立于编程语言的文本格式来存储和表示数据。简洁和清晰的层次结构使得 JSON 成为理想的数据交换语言。 易于人阅读和编写，同时也易于机器解析和生成，并有效地提升网络传输效率。
看看数据
LandmarkData.json
[
{
"name": "Turtle Rock",
"category": "Featured",
"city": "Twentynine Palms",
"state": "California",
"id": 1001,
"park": "Joshua Tree National Park",
"coordinates": {
"longitude": -116.166868,
"latitude": 34.011286
},
"imageName": "turtlerock"
},
{
"name": "Silver Salmon Creek",
"category": "Lakes",
"city": "Port Alsworth",
"state": "Alaska",
"id": 1002,
"park": "Lake Clark National Park and Preserve",
"coordinates": {
"longitude": -152.665167,
"latitude": 59.980167
},
"imageName": "silversalmoncreek"
},
{
"name": "Chilkoot Trail",
"category": "Rivers",
"city": "Skagway",
"state": "Alaska",
"id": 1003,
"park": "Klondike Gold Rush National Historical Park",
"coordinates": {
"longitude": -135.334571,
"latitude": 59.560551
},
"imageName": "chilkoottrail"
},
{
"name": "St. Mary Lake",
"category": "Lakes",
"city": "Browning",
"state": "Montana",
"id": 1004,
"park": "Glacier National Park",
"coordinates": {
"longitude": -113.536248,
"latitude": 48.69423
},
"imageName": "stmarylake"
},
{
"name": "Twin Lake",
"category": "Lakes",
"city": "Twin Lakes",
"state": "Alaska",
"id": 1005,
"park": "Lake Clark National Park and Preserve",
"coordinates": {
"longitude": -153.849883,
"latitude": 60.641684
},
"imageName": "twinlake"
},
{
"name": "Lake McDonald",
"category": "Lakes",
"city": "West Glacier",
"state": "Montana",
"id": 1006,
"park": "Glacier National Park",
"coordinates": {
"longitude": -113.934831,
"latitude": 48.56002
},
"imageName": "lakemcdonald"
},
{
"name": "Charley Rivers",
"category": "Rivers",
"city": "Eaking",
"state": "Alaska",
"id": 1007,
"park": "Charley Rivers National Preserve",
"coordinates": {
"longitude": -143.122586,
"latitude": 65.350021
},
"imageName": "yukon_charleyrivers"
},
{
"name": "Icy Bay",
"category": "Lakes",
"city": "Icy Bay",
"state": "Alaska",
"id": 1008,
"park": "Wrangell-St. Elias National Park and Preserve",
"coordinates": {
"longitude": -141.518167,
"latitude": 60.089917
},
"imageName": "icybay"
},
{
"name": "Rainbow Lake",
"category": "Lakes",
"city": "Willow",
"state": "Alaska",
"id": 1009,
"park": "State Recreation Area",
"coordinates": {
"longitude": -150.086103,
"latitude": 61.694334
},
"imageName": "rainbowlake"
},
{
"name": "Hidden Lake",
"category": "Lakes",
"city": "Newhalem",
"state": "Washington",
"id": 1010,
"park": "North Cascades National Park",
"coordinates": {
"longitude": -121.17799,
"latitude": 48.495442
},
"imageName": "hiddenlake"
},
{
"name": "Chincoteague",
"category": "Rivers",
"city": "Chincoteague",
"state": "Virginia",
"id": 1011,
"park": "Chincoteague National Wildlife Refuge",
"coordinates": {
"longitude": -75.383212,
"latitude": 37.91531
},
"imageName": "chincoteague"
},
{
"name": "Lake Umbagog",
"category": "Lakes",
"city": "Errol",
"state": "New Hampshire",
"id": 1012,
"park": "Umbagog National Wildlife Refuge",
"coordinates": {
"longitude": -71.056816,
"latitude": 44.747408
},
"imageName": "umbagog"
}
]
读取json并转化为数组
- 定义一个struct存储数据
import SwiftUI
import CoreLocation
struct Landmark: Hashable, Codable, Identifiable {
var id: Int
var name: String
fileprivate var imageName: String
fileprivate var coordinates: Coordinates
var state: String
var park: String
var category: Category
var locationCoordinate: CLLocationCoordinate2D {
CLLocationCoordinate2D(
latitude: coordinates.latitude,
longitude: coordinates.longitude)
}
enum Category: String, CaseIterable, Codable, Hashable {
case featured = "Featured"
case lakes = "Lakes"
case rivers = "Rivers"
}
}
extension Landmark {
var image: Image {
ImageStore.shared.image(name: imageName)
}
}
struct Coordinates: Hashable, Codable {
var latitude: Double
var longitude: Double
}
- 从json中提取数据