SharedPreferences With Kotlin Extn funcs = Life Easy!

AppComponent.kt

@Singleton
@Component(
        modules = [(SharedPreferenceModule::class),
            (APIModule::class),
            (RepositoryModule::class),
            (DataBaseModule::class),
            (DBRefreshingModule::class), ....]
)
interface AppComponent {
    //  app's application class
    fun inject(into: AppDelegate)
}

AppDelegate.kt

class AppDelegate : Application() {

    lateinit var appDaggerComponent: AppComponent
        private set
  
    @Inject
    lateinit var sPreferences: SharedPreferences

    @Inject
    lateinit var sPreferencesEditor: SharedPreferences.Editor

    override fun onCreate() {
        super.onCreate()
        INSTANCE = this
        appDaggerComponent = DaggerAppComponent
                .builder()
                .applicationModule(ApplicationModule(this))
                .aPIModule(APIModule())
                .repositoryModule(RepositoryModule())
                .build()
        appDaggerComponent.inject(this)
    }
}

AppExtnFuncs.kt

fun Any.writeToPref(tag: String,
                    prefEditor: SharedPreferences.Editor = AppDelegate.INSTANCE.sPreferencesEditor) {
    when (this) {
        is String -> prefEditor.putString(tag, this)

        is Int -> prefEditor.putInt(tag, this)

        is Long -> prefEditor.putLong(tag, this)

        is Boolean -> prefEditor.putBoolean(tag, this)

        is Float -> prefEditor.putFloat(tag, this)

        else -> throw IllegalArgumentException(ConstantsUtil.INVALID_INPUT_SHARED_PREFERENCE)
    }
    prefEditor.commit()
}

fun String.readStringFromPref(sPreferences: SharedPreferences = AppDelegate.INSTANCE.sPreferences): String =
        sPreferences.getString(this, ConstantsUtil.EMPTY)

fun String.readIntFromPref(sPreferences: SharedPreferences = AppDelegate.INSTANCE.sPreferences): Int =
        sPreferences.getInt(this, 0)

fun String.readLongFromPref(sPreferences: SharedPreferences = AppDelegate.INSTANCE.sPreferences): Long =
        sPreferences.getLong(this, 0L)

fun String.readBooleanFromPref(sPreferences: SharedPreferences = AppDelegate.INSTANCE.sPreferences): Boolean =
        sPreferences.getBoolean(this, false)

fun String.readFloatFromPref(sPreferences: SharedPreferences = AppDelegate.INSTANCE.sPreferences): Float =
        sPreferences.getFloat(this, 0f)

fun String.removeFromPref(prefEditor: SharedPreferences.Editor = AppDelegate.INSTANCE.sPreferencesEditor) {
    prefEditor.remove(this)
    prefEditor.commit()
}

fun Any.removeTheseFromPref(
        vararg keys: String,
        prefEditor: SharedPreferences.Editor = AppDelegate.INSTANCE.sPreferencesEditor) {
    keys.forEach {
        prefEditor.remove(it)
    }
    prefEditor.commit()
}

fun SharedPreferences.Editor.clearPref() {
    this.clear()
    this.commit()
}

fun Any.showVLog(log: String) = Log.v(this::class.java.simpleName, log)

AppModule.kt

@Module
class SharedPreferenceModule {

    @Provides
    @Singleton
    fun giveAppPreference(): SharedPreferences =
            AppDelegate.INSTANCE.getSharedPreferences(ConstantsUtil.APP_SHARED_PREF_NAME, Context.MODE_PRIVATE)

    @SuppressLint("CommitPrefEdits")
    @Provides
    @Singleton
    fun giveAppPreferenceEditor(pref: SharedPreferences): SharedPreferences.Editor =
            pref.edit()
}

DemoActivity.kt

class DemoActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        "jack and jill went up the hill".writeToPref("poem")
        1.writeToPref("one")
        3f.writeToPref("threeF")
        7L.writeToPref("sevenLong")
        true.writeToPref("booo")

        showVLog("poem".readStringFromPref())
        showVLog("one".readIntFromPref().toString())
        showVLog("threeF".readFloatFromPref().toString())
        showVLog("sevenLong".readLongFromPref().toString())
        showVLog("booo".readBooleanFromPref().toString())
      
        //        O/P
        //         V/---DemoActivity: jack and jill went up the hill
        //         V/---DemoActivity: 1
        //         V/---DemoActivity: 3.0
        //         V/---DemoActivity: 7
        //         V/---DemoActivity: true

    }
}