Android: insert one ArrayList into for() loop from multiple ArrayLists

I have a filter method in MainActivity for two ArrayLists, smallList and mainList.

How can I write for() loop code to select one of the lists based on the criteria shown, so that I don't have to use two for() loops?

private void filter(String searchText) {

    ArrayList<Card> searchList = new ArrayList<>();

    // Determine which RecyclerView list to use and then run a for() loop that     
    // searches the database for input search text.

    if (smallList != null && !smallList.isEmpty()) {
        for (Card cardItem : **smallList**) {
            if (cardItem.getInfo().contains(searchText)) {
                searchList.add(cardItem);
            }
        }
    }
    else {
        for (Card cardItem : **mainList**) {
            if (cardItem.getInfo().contains(searchText)) {
                searchList.add(cardItem);
            }
        }
    }
    ...
}

I'm not sure if this is what you mean, but anyway, here goes.
You simply first determine which List you want to search. Then you search only that List. Hence single for loop.

java.util.List<Card> list = smallList != null && !smallList.isEmpty() ? smallList : mainList;
for (Card cardItem : list) {
    if (cardItem.getInfo().contains(searchText)) {
        searchList.add(cardItem);
    }
}