Swift - Encode and Decode a dictionary [String:Any] into plist

Question

I am trying to store the dictionary in my class Marker but it is throwing an error saying it is not encodable or decodable. I can see the error is caused by the [String: Any] but how can I go around it?

var buttonActions : [String: [String: [String:Any]]] = [:]

Save and Load

func saveData() {
    let dataFilePath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("\(fileName).plist")

    let encoder = PropertyListEncoder()
    do {
        let data = try encoder.encode(markerArray)
        try data.write(to: dataFilePath!)
        print("Saved")
    } catch {
        print("Error Encoding \(error)")
    }
}

func loadData() {
    let dataFilePath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("\(fileName).plist")

    if let data = try? Data(contentsOf: dataFilePath!){
        let decoder = PropertyListDecoder()
        do {
            markerArray = try decoder.decode([Marker].self, from: data)
        } catch {
            print("Decode Error \(error)")
        }
    }

Class

class Marker : Encodable, Decodable {
    var UUIDpic: UUID = UUID()
    var alpha: Int = 1
    var buttonType: Int = 0
    var buttonActions : [String: [String: [String:Any]]] = [:]
    var buttonNameColor: String = ""
    var buttonNameFontSize: Int = 10
    var buttonShape: String = ""
    var loggerRect: String = ""
    var maskColor: String = ""
    var name: String = ""
}

Answer 1

Unfortunately you cannot use encode or decode on generic types containing Any (e.g. [String: Any] or [Any]). Any does not conform to protocols Encodable nor Decodable and Swift doesn't know how to encode/decode it. You must use a concrete generic type for your dictionary (e.g. [String: String]).

If you still need to use a general type like Any you have to implement encode(to:) and init(from:) methods. Another option would be to use a struct instead of your [String: [String: [String:Any]]] which conforms to Codable (Encodable & Decodable). You will still have to implement encode(to:) and init(from:) methods in that struct, but the bright side is that you will not have to write the encoder.encode() story for all the properties like you would have to if you implement them in the Marker class.