[SwiftUI] UserDefaults -> AppStorage

@AppStorage("isLoggedIn") var isLoggedIn : Bool = UserDefaults.standard.bool(forKey: "isLoggedIn")

이런식으로 PropertyWrapper을 달아서 쓸 수 있다!

 

만약 Unsupported Type이라면 이런 extension을 달아서 해결할 수 있다. 

 

extension Array: RawRepresentable where Element: Codable {
    public init?(rawValue: String) {
        guard let data = rawValue.data(using: .utf8),
              let result = try? JSONDecoder().decode([Element].self, from: data)
        else {
            return nil
        }
        self = result
    }

    public var rawValue: String {
        guard let data = try? JSONEncoder().encode(self),
              let result = String(data: data, encoding: .utf8)
        else {
            return "[]"
        }
        return result
    }
}

 

struct ContentView: View {
    @AppStorage("itemsInt") var itemsInt = [1, 2, 3]
    @AppStorage("itemsBool") var itemsBool = [true, false, true]

    var body: some View {
        VStack {
            Text("itemsInt: \(String(describing: itemsInt))")
            Text("itemsBool: \(String(describing: itemsBool))")
            Button("Add item") {
                itemsInt.append(Int.random(in: 1...10))
                itemsBool.append(Int.random(in: 1...10).isMultiple(of: 2))
            }
        }
    }
}