Preference.kt

import android.content.SharedPreferences
import kotlin.properties.ReadWriteProperty
import kotlin.reflect.KProperty

class Preference<T>(
    private val preferences: SharedPreferences,
    private val name: String,
    private val default: T
) : ReadWriteProperty<Any?, T> {

    override fun getValue(thisRef: Any?, property: KProperty<*>): T = findPreference(name, default)

    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
        putPreference(name, value)
    }

    private fun <T> findPreference(name: String, default: T): T = with(preferences) {
        val res: Any = when (default) {
            is Long -> getLong(name, default)
            is String -> getString(name, default)
            is Int -> getInt(name, default)
            is Boolean -> getBoolean(name, default)
            is Float -> getFloat(name, default)
            else -> throw IllegalArgumentException("This type cannot be saved into Preferences")
        }
        res as? T ?: default
    }

    private fun <T> putPreference(name: String, value: T) = with(preferences.edit()) {
        when (value) {
            is Long -> putLong(name, value)
            is String -> putString(name, value)
            is Int -> putInt(name, value)
            is Boolean -> putBoolean(name, value)
            is Float -> putFloat(name, value)
            else -> throw IllegalArgumentException("This type cannot be saved into Preferences")
        }.apply()
    }
}

// SAMPLE

// before you need ref to SharedPreference
    var myValue: String by Preference(
        preference,
        "KEY",
        "DEFAULT_VALUE"
    )

// put new value to shared pref
  myValue = "NEW_VALUE"