Android Java - I need to sort a list based on another list

Asked Apr 30 '19 at 19:37

Active Apr 30 '19 at 19:52

Viewed 39 times

One list with animals:(unsorted) e.g ["Lion","Tiger","Cat", "Dog", "Cuy"]

Another list animals_select: e.g ["Cuy", "Cat"]

I'm trying to sort the animals list based on the values of the second list.

Code:

List<String> animals = new ArrayList<>();

// Adding new elements to the ArrayList
animals.add("Lion");
animals.add("Tiger");
animals.add("Cat");
animals.add("Dog");
animals.add("Cuy");

System.out.println(animals);

//["Lion","Tiger","Cat", "Dog"]

List<String> animals_select = new ArrayList<>();
animals_select.add("Cat");
animals_select.add("Cuy");

I want to get a list like this ["Cuy", "Cat", "Lion","Tiger", "Dog"]

Those in the second list should be ordered first

I have tried without success

Collections.sort(animals, new Comparator() {
                    public int compare(left, right) {
                        return Integer.compare(animals_select.indexOf(left), animals_select.indexOf(right));
                    }
                });

edited Apr 30 '19 at 19:52

asked Apr 30 '19 at 19:37

zetanova

What have you tried that didn't work? – Bakon Jarser Apr 30 '19 at 19:44
Collections.sort(animals, new Comparator() { public int compare(left, right) { return Integer.compare(animals_select.indexOf(left), animals_select.indexOf(right)); } }); – zetanova Apr 30 '19 at 19:45
Does it matter if the sorted list is Cuy, Cat, Lion, ... or Cat, Cuy, Lion, ...? – Bakon Jarser Apr 30 '19 at 19:48
@Bakon Jarser either, – zetanova Apr 30 '19 at 19:50
1

Just loop through the second list, removing strings from the first list (if they are in the list) and add them back at index 0. (Note: this won't work for all Objects, strings are an exception because of how their .equals() is implemented). – Bakon Jarser Apr 30 '19 at 19:55
this has worked thanks – zetanova Apr 30 '19 at 20:18

Android Java - I need to sort a list based on another list

0 Answers0