像往常一样，用字符串当key 缺点：
- 容易拼写错误
- 重复定义
- 多人开发项目,难于管理
eg:
import Foundation
import UIKit
protocol UserDefaultNameSpace {}
extension UserDefaultNameSpace {
static func namespace<T>(_ key:T) -> String where T: RawRepresentable {
return "\(Self.self).\(key.rawValue)"
}
}
protocol UserDefaultSettable: UserDefaultNameSpace {
associatedtype UserDafaultKey: RawRepresentable
}
extension UserDefaultSettable where UserDafaultKey.RawValue == String {}
extension UserDefaultSettable {
/// 关于 Int 类型的存储和读取
static func set(value: Int, forKey key: UserDafaultKey) {
let key = namespace(key)
UserDefaults.standard.set(value, forKey: key)
}
static func integer(value: Int, forKey key: UserDafaultKey) {
let key = namespace(key)
UserDefaults.standard.integer(forKey: key)
}
/// 关于 String 类型存储和读取
static func set(value: Any?, forKey key: UserDafaultKey) {
let key = namespace(key)
UserDefaults.standard.set(value, forKey: key)
}
static func string(value: Any?, forKey key: UserDafaultKey) {
let key = namespace(key)
UserDefaults.standard.string(forKey: key)
}
}
// MARK: - 使用方式
extension UserDefaults {
struct Account: UserDefaultSettable {
enum UserDafaultKey: String {
case name
case age
case birth
}
}
}
class test {
func testFunction() {
UserDefaults.Account.set(value: 20, forKey: .age)
UserDefaults.Account.set(value: "hjq", forKey: .name)
}
}
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