SharedPreferencesProperty.kt

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

class SharedPreferencesProperty<T>(val sharedPreferences: SharedPreferences,
                                   val key: String,
                                   val get: SharedPreferences.(String) -> T,
                                   val put: SharedPreferences.Editor.(String, T) -> SharedPreferences.Editor) : ReadWriteProperty<Any, T> {

    companion object {
        fun of(sharedPreferences: SharedPreferences, key: String, defaultValue: String) =
                SharedPreferencesProperty(sharedPreferences, key,
                        { getString(it, defaultValue) }, SharedPreferences.Editor::putString)

        fun of(sharedPreferences: SharedPreferences, key: String, defaultValue: Boolean) =
                SharedPreferencesProperty(sharedPreferences, key,
                        { getBoolean(it, defaultValue) }, SharedPreferences.Editor::putBoolean)

        fun of(sharedPreferences: SharedPreferences, key: String, defaultValue: Int) =
                SharedPreferencesProperty(sharedPreferences, key,
                        { getInt(it, defaultValue) }, SharedPreferences.Editor::putInt)
    }

    override fun getValue(thisRef: Any, property: KProperty<*>): T {
        return sharedPreferences.get(key)
    }

    override fun setValue(thisRef: Any, property: KProperty<*>, value: T) {
        sharedPreferences.edit().put(key, value).apply()
    }
}

@ApplicationScope
class ApplicationPreferences @Inject constructor(context: Context) {

    private val pref = context.getSharedPreferences("ApplicationPreferences", Context.MODE_PRIVATE)

    var isTermsAgreed by SharedPreferencesProperty.of(pref, "isTermisAgreed", false)
    var uuid by SharedPreferencesProperty.of(pref, "uuid", "")
}