構造体の保存

Codable + UserDefaults で保存する。

Codable + UserDefaults で保存する。

正しい保存

struct CCC: Codable {
    var aaa: String
    var bbb: BBB
}

struct BBB: Codable {
    var ccc: String
}

class TestClass {
    var c: CCC?
    
    func ee() {
        c = CCC(aaa: "123", bbb: BBB(ccc: "456"))
        
        if let data = try? JSONEncoder().encode(c) {
            UserDefaults.standard.set(data, forKey: "test")
            print("保存成功")
        }
    }
    
    func ff() {
        do {
            guard let a = UserDefaults.standard.data(forKey: "test") else {
                throw NSError(domain: "", code: 0, userInfo: nil) }
            c = try JSONDecoder().decode(CCC.self, from: a)
            print("読み込み成功")
        } catch {
            print("読み込み失敗")
        }
    }
}

struct CCC: Codable {

var aaa: String

var bbb: BBB

}

struct BBB: Codable {

var ccc: String

}

class TestClass {

var c: CCC?

func ee() {

c = CCC(aaa: "123", bbb: BBB(ccc: "456"))

if let data = try? JSONEncoder().encode(c) {

UserDefaults.standard.set(data, forKey: "test")

print("保存成功")

}

func ff() {

do {

guard let a = UserDefaults.standard.data(forKey: "test") else {

throw NSError(domain: "", code: 0, userInfo: nil) }

c = try JSONDecoder().decode(CCC.self, from: a)

print("読み込み成功")

} catch {

print("読み込み失敗")

}

失敗例(構造体の初期化がNG)

struct CCC: Codable {
    var aaa: String
    var bbb: BBB
}

struct BBB: Codable {
    var ccc: String
}

class TestClass {
    var c: CCC?
    
    func ee() {
        c?.aaa = "123"
        c?.bbb.ccc = "456"
        
        if let data = try? JSONEncoder().encode(c) {
            UserDefaults.standard.set(data, forKey: "test")
            print("保存成功")
        }
    }
    
    func ff() {
        do {
            guard let a = UserDefaults.standard.data(forKey: "test") else {
                throw NSError(domain: "", code: 0, userInfo: nil) }
            c = try JSONDecoder().decode(CCC.self, from: a)
            print("読み込み成功")
        } catch {
            print("読み込み失敗")
        }
    }
}