Question

What would be a good list structure to use when I want to loop trough it and back again and so on? I’m now using a extended ArrayList with a custom method for looping it forward and backward etc.

Does Java (Android) offer a list type that I can use without extending it’s behavior?

If not, what would be the best way to code a list for this use-case?

My current code looks a bit like this:

if(!back){
    if(hasNext()){
        return next();
    } else {
        back = true;
        return previous();
    }
} else {
    if(hasPrevious()){
        return previous();
    } else {
        back = false;
        return next();
    }
}

Answer 1

A LinkedList is exactly what you’re looking for. It’s default iterator is a forward iterator, but it also provides a descendingIterator