SwiftUI - How to save custom class data to UserDefaults? - ios

Question

I have created a custom class (as an ObservedObject since I need to share this data).
Everything works but when I force close the app the data resets and I have not found any way to save it to UserDefaults. (Trying to save normally as an object crashed the app).
How can I save this data? (When pressing the button in SettingsView)
First time asking here.
---MainView---
import SwiftUI
class ProgressData: ObservableObject {
#Published var licenseDate: Date = Date()
#Published var dayProgressValue: Float = 0.00
#Published var nightProgressValue: Float = 0.00
#Published var newDriverProgressValue: Float = 0.00
}
struct MainView: View {
let defualts = UserDefaults.standard
#ObservedObject var data = ProgressData()
var body: some View {
// App Code Here!
}
--- SettingsView ---
import SwiftUI
struct SettingsView: View {
#ObservedObject var data: ProgressData
var body: some View {
Button(action: {
// What to do in order to save it here?
})
}
Thanks.

Answer 1

In order to do so, all you have to do is make sure your custom class is comforting the Codable protocol.
class ProgressData: ObservableObject, Codable {
#Published var licenseDate: Date = Date()
#Published var dayProgressValue: Float = 0.00
#Published var nightProgressValue: Float = 0.00
#Published var newDriverProgressValue: Float = 0.00
}
Next, you need to save it to UserDefault like that:
import SwiftUI
struct SettingsView: View {
#ObservedObject var data: ProgressData
var body: some View {
Button(action: {
let encoder = JSONEncoder()
if let encoded = try? encoder.encode(data) {
UserDefaults.standard.set(encoded, forKey: "saved_data")
}
})
}
}
When you want to pull your saved data from UserDefaults, all you have to do it:
if let data = defaults.object(forKey: "saved_data") as? Data {
let decoder = JSONDecoder()
if let savedData = try? decoder.decode(ProgressData.self, from: data) {
// Do wantever you want with `savedData`
}
}
You can read a bit more about it, in this wonderful article