Simple SharedPrefs

Android library written in Kotlin to simplify use of SharedPreferences.

Setup

Add the JitPack repository to your build file

allprojects {
  repositories {
    maven { url 'https://jitpack.io' }
  }
}

Add library dependency to your project build file

dependencies {
  implementation 'com.github.cregus:simple-shared-prefs:1.0.2'
}

Sample usage

Define prefs class and some properties using provided delegates

class AppPrefs(sharedPreferences: SharedPreferences) : SharedPrefs(sharedPreferences) {
    var isAuthorized by booleanPreference()
    var userName by stringPreference()
}

Use it

val appPrefs = AppPrefs(PreferenceManager.getDefaultSharedPreferences(context))

if (appPrefs.isAuthorized) {
  appPrefs.userName = "John Doe"
}

Config

You can use all data types that can be stored in shared preferences. Default values and delegates are:

Type	Value	Delegate
Boolean	false	booleanPreference()
Int	0	intPreference()
Long	0L	longPreference()
Float	0f	floatPreference()
String	null	stringPreference()
Set<String>	null	stringSetPreference()

You can change default value by passing it to delegate method:

var isDarkTheme by booleanPreference(defaultValue = true)

String and Set<String> are nullable types until you provide default value, for example:

var userName: String? by stringPreference()
var themeColor: String by stringPreference(defaultValue = "#F44336")

You can also change preference key (it's property name by default) and switch from apply to commit save method:

var authToken by stringPreference(commit = true, key = "auth_token")

If you need to store other types of data you need to provide mapper:

object DateMapper : PreferenceMapper<Date, Long> {
    override fun fromStored(stored: Long): Date {
        return Date(stored)
    }

    override fun toStored(value: Date): Long {
        return value.time
    }
}

And now it can be stored using mapped version of delegate:

var lastUpdateCheck by mappedLongPreference(mapper = DateMapper, defaultValue = Date())