@SuppressWarnings("unchecked")
    private void enableAppLockerIfDoesNotExist() {
        try {
            if (mLockManager.getAppLock() == null) {
                mLockManager.enableAppLock(this, getCustomAppLockActivityClass());
            }
        } catch (Exception e) {
            Log.e(TAG, e.toString());
        }
    }
Re enable {@link AppLock} if it has been collected to avoid
{@link NullPointerException}.
lib/src/main/java/com/github/omadahealth/lollipin/lib/managers/AppLockActivity.java