- 自定义对象需要遵守
Codable协议
import Foundation
struct BookItem: Codable {
var bookName: String
var bookDescribe: String
var bookPrice: Float
//区别 可以将字典中`name`的值解析到`bookName`
fileprivate enum CodingKeys: String, CodingKey {
case bookName = "name"
case bookDescribe
case bookPrice
}
}
-
vc中调用
fileprivate func codableDemo() {
//1. json字符串转自定义对象
let json = """
{
"name": "米饭童鞋",
"bookPrice": 200.87,
"bookDescribe": "A handsome boy."
}
"""
//2. string -> data
guard let data = json.data(using: .utf8) else {
return
}
//3. data -> item
let decoder = JSONDecoder()
guard let book = try? decoder.decode(BookItem.self, from: data) else {
return
}
print(book, book.bookName, book.bookPrice, book.bookDescribe)
//4. 自定义对象存 UserDefaults
UserDefaults.standard.setItem(book, forKey: "book")
guard let bk1 = UserDefaults.standard.getItem(BookItem.self, forKey: "book") else {
return
}
print(bk1)
}
-
UserDefaults扩展
extension UserDefaults {
func setItem<T: Encodable>(_ object: T, forKey key: String) {
let encoder = JSONEncoder()
guard let encoded = try? encoder.encode(object) else {
return
}
self.set(encoded, forKey: key)
}
func getItem<T: Decodable>(_ type: T.Type, forKey key: String) -> T? {
guard let data = self.data(forKey: key) else {
return nil
}
let decoder = JSONDecoder()
guard let object = try? decoder.decode(type, from: data) else {
print("Couldnt find key")
return nil
}
return object
}
}
- 打印
BookItem(bookName: "米饭童鞋", bookDescribe: "A handsome boy.", bookPrice: 200.87) 米饭童鞋 200.87 A handsome boy.
BookItem(bookName: "米饭童鞋", bookDescribe: "A handsome boy.", bookPrice: 200.87)
