@Override
  public void onDestroy() {
    super.onDestroy();
    if (contactSyncListener != null) {
      MyHelper.getInstance().removeSyncContactListener(contactSyncListener);
      contactSyncListener = null;
    }

    if (blackListSyncListener != null) {
      MyHelper.getInstance().removeSyncBlackListListener(blackListSyncListener);
    }

    if (contactInfoSyncListener != null) {
      MyHelper.getInstance()
          .getUserProfileManager()
          .removeSyncContactInfoListener(contactInfoSyncListener);
    }
  }