Android Shared Preferences Delegate for Kotlin

import android.content.Context
import android.content.SharedPreferences
import android.preference.PreferenceManager
import java.util.*
import kotlin.reflect.KProperty

/*
 * Android Shared Preferences Delegate for Kotlin
 *
 * Usage:
 *
 * PrefDelegate.init(context)
 * ...
 * var accessToken by stringPref(PREFS_ID, "access_token")
 * var appLaunchCount by intPref(PREFS_ID, "app_launch_count", 0)
 * var autoRefreshEnabled by booleanPref("auto_refresh enabled") // using Default Shared Preferences
 *
 */

abstract class PrefDelegate<T>(val prefName: String?, val prefKey: String) {

    companion object {
        private var context: Context? = null

        /**
         * Initialize PrefDelegate with a Context reference
         * !! This method needs to be called before any other usage of PrefDelegate !!
         */
        fun init(context: Context) {
            this.context = context
        }
    }

    protected val prefs: SharedPreferences by lazy {
        if (context != null)
            if (prefName != null) context!!.getSharedPreferences(prefName, Context.MODE_PRIVATE) else PreferenceManager.getDefaultSharedPreferences(context!!)
        else
            throw IllegalStateException("Context was not initialized. Call PrefDelegate.init(context) before using it")
    }

    abstract operator fun getValue(thisRef: Any?, property: KProperty<*>): T
    abstract operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T)
}

fun stringPref(prefKey: String, defaultValue: String? = null) = StringPrefDelegate(null, prefKey, defaultValue)
fun stringPref(prefName: String, prefKey: String, defaultValue: String? = null) = StringPrefDelegate(prefName, prefKey, defaultValue)
class StringPrefDelegate(prefName: String?, prefKey: String, val defaultValue: String?) : PrefDelegate<String?>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getString(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) = prefs.edit().putString(prefKey, value).apply()
}

fun intPref(prefKey: String, defaultValue: Int = 0) = IntPrefDelegate(null, prefKey, defaultValue)
fun intPref(prefName: String, prefKey: String, defaultValue: Int = 0) = IntPrefDelegate(prefName, prefKey, defaultValue)
class IntPrefDelegate(prefName: String?, prefKey: String, val defaultValue: Int) : PrefDelegate<Int>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getInt(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Int) = prefs.edit().putInt(prefKey, value).apply()
}

fun floatPref(prefKey: String, defaultValue: Float = 0f) = FloatPrefDelegate(null, prefKey, defaultValue)
fun floatPref(prefName: String, prefKey: String, defaultValue: Float = 0f) = FloatPrefDelegate(prefName, prefKey, defaultValue)
class FloatPrefDelegate(prefName: String?, prefKey: String, val defaultValue: Float) : PrefDelegate<Float>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getFloat(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Float) = prefs.edit().putFloat(prefKey, value).apply()
}

fun booleanPref(prefKey: String, defaultValue: Boolean = false) = BooleanPrefDelegate(null, prefKey, defaultValue)
fun booleanPref(prefName: String, prefKey: String, defaultValue: Boolean = false) = BooleanPrefDelegate(prefName, prefKey, defaultValue)
class BooleanPrefDelegate(prefName: String?, prefKey: String, val defaultValue: Boolean) : PrefDelegate<Boolean>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getBoolean(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) = prefs.edit().putBoolean(prefKey, value).apply()
}

fun longPref(prefKey: String, defaultValue: Long = 0L) = LongPrefDelegate(null, prefKey, defaultValue)
fun longPref(prefName: String, prefKey: String, defaultValue: Long = 0L) = LongPrefDelegate(prefName, prefKey, defaultValue)
class LongPrefDelegate(prefName: String?, prefKey: String, val defaultValue: Long) : PrefDelegate<Long>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getLong(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Long) = prefs.edit().putLong(prefKey, value).apply()
}

fun stringSetPref(prefKey: String, defaultValue: Set<String> = HashSet<String>()) = StringSetPrefDelegate(null, prefKey, defaultValue)
fun stringSetPref(prefName: String, prefKey: String, defaultValue: Set<String> = HashSet<String>()) = StringSetPrefDelegate(prefName, prefKey, defaultValue)
class StringSetPrefDelegate(prefName: String?, prefKey: String, val defaultValue: Set<String>) : PrefDelegate<Set<String>>(prefName, prefKey) {
    override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getStringSet(prefKey, defaultValue)
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Set<String>) = prefs.edit().putStringSet(prefKey, value).apply()
}

Once we store value from one activity, how we can access the same value from another Activity?
Can you provide me code for this task?
Thanks in advance

PreferenceManager is deprecated, any ideas?

PreferenceManager is deprecated, any ideas?

you need to use androidx.preference now.