Best approach to persist preferences of several User ( NSUserDefaults, XML file or Database)

Question

I am creating one iOS app with the possibility of managing users and login them.

I want to persist the user data settings of every user but I´m not sure what is the best way to do save this setting by each user.

Should I save the data into an xml file, or NSUserDefaults or even saving them into my Parse Cloud Database?

I just want to save a list of user properties when loading a view, but I must have in consideration that my App must load the right parameter for current user.

For example:

User: Peter trackingSwitchEnabled: YES

User: Molly trackingSwitchEnabled: NO

User: Paul trackingSwitchEnabled: YES

Answer 1

• Don't use the keychain unless you are storing sensitive information.
• Don't use Core Data or XML (unless it's a plist) because it's a lot of work.
• Don't use Parse unless you have a reason to, because your user data would depend on you paying for an account, and the users having connectivity.
• Use NSUserDefaults with key=user, value=JSON string. You can parse that to/from an object.
• Use a compound key if you are extra-lazy, e.g.: key="Mary|tracking", value=YES.

Bonus ASCII art!

                           NSUserDefaults   plist    Core Data   SQList
    Full text search           ✘              ✘          ✘         ✔
    Complex search             ✘              ✘          ✔         ✔
    Binary data                ✘              ✘          ✔         ✔
    Allows complex data        ★              ★★        ★★★★     ★★★★
    Performance                ★              ★         ★★★      ★★★★
    Learning curve             ★              ★★        ★★★      ★★★★

Answer 2

If you want to use NSUserDefaults, you should use initWithSuiteName: to create different database.

[[NSUserDefaults alloc] initWithSuiteName:USER_IDENTIFY]