removeItem method
API to remove item.
Parameters:
id ID to be removed.
Exceptions:
Throws an ArgumentError if the ID is empty.
Throws an ArgumentError if there is no item associated with the ID.
Implementation
void removeItem(String id) {
int index;
if (id.isEmpty) {
throw ArgumentError("removeItem : You must set id.");
} else if ((index = _getIndex(0, id)) < 0) {
throw ArgumentError("removeItem : There is no item associated with the ID.");
}
items?.removeAt(index);
}