idish

abstract class SharedPreferenceLiveData<T> extends LiveData<T> {

    SharedPreferences sharedPrefs;
    String key;
    T defValue;

    public SharedPreferenceLiveData(SharedPreferences prefs, String key, T defValue) {
        this.sharedPrefs = prefs;
        this.key = key;
        this.defValue = defValue;

rharter

import android.arch.lifecycle.LiveData
import android.content.SharedPreferences

abstract class SharedPreferenceLiveData<T>(val sharedPrefs: SharedPreferences,
                                  val key: String,
                                  val defValue: T) : LiveData<T>() {

  private val preferenceChangeListener = SharedPreferences.OnSharedPreferenceChangeListener { sharedPreferences, key ->
    if (key == this.key) {
      value = getValueFromPreferences(key, defValue)