What's the point of having a default value in sharedPref.getString?

Question

I\'m accessing my Android apps SharedPreferences via

private val sharedPref = PreferenceManager.getDefaultSharedPreferences(context)`
         


        

Answer 1

SharedPreferences is an abstraction over Key/Value databasing provided by Google, how you use it is up to you. If you dislike this syntax, then create a wrapper or extension for your getString(). Just to give an example:

fun PreferenceManager.getStringTheFancyWay(key: String, defaultValue: String): String {
    return getString(key, defaultValue) ?: defaultValue
}
val value = getStringTheFancyWay("a", "b")

Personally I dislike this, because null allows for a better control flow over non-existing keys.

This is how I use SharedPreferences

val preferences = PreferenceManager.getDefaultSharedPreferences(context)
val value = preferences.getString("username", null)
if (value != null) {
    toast("Hello $value")
} else {
    toast("Username not found")
}

or

preferences.getString("username", null)?.let { username ->
    toast("Hello $username")
}

Notice the difference?