An Utility class for kotlin to make use of shared preference easy and robust. Very convenient for access shared pref values like how we access other class variables.

SharedPreferenceUtil.kt

import android.content.Context
import android.content.SharedPreferences

object SharedPreferenceUtil {
    private const val NAME = "__arif"
    private const val MODE = Context.MODE_PRIVATE
    private lateinit var preferences: SharedPreferences


    private val IS_FIRST_RUN_PREF = Pair("is_first_run", true)
    private val LAST_SELECTED_COLOR = Pair("last.color.sel", null)

  // call this method from application onCreate(once)
    fun init(context: Application) {
        preferences = context.getSharedPreferences(NAME, MODE)
    }

    /**
     * SharedPreferences extension function, so we won't need to call edit()
    and apply()
     * ourselves on every SharedPreferences operation.
     */
    private inline fun SharedPreferences.edit(
        operation:
            (SharedPreferences.Editor) -> Unit
    ) {
        val editor = edit()
        operation(editor)
        editor.apply()
    }
    

    var firstRun: Boolean
        get() = preferences.getBoolean(IS_FIRST_RUN_PREF.first, IS_FIRST_RUN_PREF.second)
        set(value) = preferences.edit {
            it.putBoolean(IS_FIRST_RUN_PREF.first, value)
        }

    

    var lastSelectedColor: String?
        get() = preferences.getString(LAST_SELECTED_COLOR.first, LAST_SELECTED_COLOR.second)
        set(value) = preferences.edit {
            it.putString(LAST_SELECTED_COLOR.first, value)
        }
        
    fun saveBoolean(key: String, value: Boolean) {
        preferences.edit {
            it.putBoolean(key, value)
        }
    }
    fun getBoolean(key: String, defaultValue: Boolean): Boolean {
        return preferences.getBoolean(key, defaultValue)
    }

    fun hasValue(toString: String): Boolean {
        return preferences.contains(toString)
    }

}