Andrew Miotke

Posting about IT stuff. Sometimes programming, usually Python or Swift.

AppStorage is not a secure storage location

You shouldn’t use AppStorage for sensitive or personal information. AppStorage is really intended for app settings, such as theme (dark/light mode, etc).

Full code example below and the project can be downloaded at: code_examples/Appstorage.

Writing to @AppStorage

Writing to @AppStorage is fairly straight forward. Declare @AppStorage in one of your views as shown below. In this instance the thing we are storing is a String.

Example:

@AppStorage("username") var username: String = ""

Reading @AppStorage

Reading @AppStorage is straight forward too. In this example we’ll call our username variable in a different view by declaring the same @AppStorage line we used to write to AppStorage.

In the example below we put @AppStorage("username") var username: String = "" at the top of our view struct and can pass username into a Text view.

Example:

@AppStorage("username") var username: String = ""

var body: some View {
    Text("Username is: \(username)")
}

Full code example

ContentView.swift

import SwiftUI

struct ContentView: View {

    @AppStorage("username") var username: String = ""

    @State var showUsernameForm: Bool = false

    var body: some View {
        NavigationView {
            Group {
                Text("Username is: \(username)")
            }
            .toolbar {
                ToolbarItem {
                    Button("Change username") {
                        showUsernameForm.toggle()
                    }
                    .sheet(isPresented: $showUsernameForm) {
                        UsernameForm(showUsernameForm: $showUsernameForm)
                    }
                }
            }
        }

    }
}

UsernameForm.swift

struct UsernameForm: View {

    @Binding var showUsernameForm: Bool

    @AppStorage("username") var username: String = ""

    var body: some View {
        NavigationView {
            Form {
                TextField("Username", text: $username)
            }
            .toolbar {
                ToolbarItem {
                    Button("Save") {
                        showUsernameForm.toggle()
                    }
                }
            }
        }
    }
}