我应该如何从用户默认值更新对象值?

Question

有如下所示的结构

struct User:Codable {
static var shared = User()
var name:String!
var age:Int!
}

用户可以保存他们的信息

var userInfo = User.shared
userInfo.name = "Kevin"
userInfo.age = 28
UserDefaults.standard.set(try? PropertyListEncoder().encode(userInfo), forKey:"UserInformation")

我在下面试过

但它似乎创造了新对象

UserDefaults.standard.set(try? PropertyListEncoder().encode(userInfo.age == 32), forKey:"UserInformation")

是否可以仅从用户默认更新用户信息对象？

喜欢只更改用户信息年龄 = 32

Answer 1

您需要解码对象，更改其值，然后再次编码：

guard let data = UserDefaults.standard.data(forKey: "UserInformation") else {
// no data associated with the key!
}
guard var obj = try? PropertyListDecoder().decode(User.self, from: data) else {
// something wrong happened with decoding 
}
obj.age = 32 // changing the object...
guard let newData = try? PropertyListEncoder().encode(obj) else {
// something wrong happened with encoding
}
UserDefaults.standard.set(newData, forKey: "UserInformation")