code: public static void setFirstLaunchDate(Context context, long firstLaunchDate) {
          SharedPreferences prefs = getSharedPreferences(context);
          SharedPreferences.Editor prefsEditor = prefs.edit();
  
          prefsEditor.putLong(PREF_KEY_APP_FIRST_LAUNCHED_DATE, firstLaunchDate);
  
          prefsEditor.commit();
      }
docs: Modify internal value.
  <p/>
  If you use this method, you might need to have a good understanding of this class code.
  
  @param context         Context
  @param firstLaunchDate First launch date.