android sharedpreferences

// load file
SharedPreferences sharedPref = getSharedPreferences(PREFERENCES_FILENAME, MODE_PRIVATE);

// read value
String value = sharedPref.getString(PREFERENCE_KEY, null);

// write value
sharedPref.edit()
  .putString(PREFERENCE_KEY, value)
  .apply();

// MY_PREFS_NAME - a static String variable like: 
//public static final String MY_PREFS_NAME = "MyPrefsFile";
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
 editor.putString("name", "Elena");
 editor.putInt("idName", 12);
 editor.apply();