How to convert a SparseArray to ArrayList?

ArrayMap looks like a better choice, which is available since API 19.

This will get just the values, ignoring gaps between indices (as your existing Map solution does):

public static <C> List<C> asList(SparseArray<C> sparseArray) {
    if (sparseArray == null) return null;
    List<C> arrayList = new ArrayList<C>(sparseArray.size());
    for (int i = 0; i < sparseArray.size(); i++)
        arrayList.add(sparseArray.valueAt(i));
    return arrayList;
}