@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); } }