How to change the order of compareBy in Kotlin

Question

I need a comparator, in Kotlin, to order every object that enter in my recycler view (using Fast Adapter).

I need to order the objects by an Integer, where the biggest ones come first.

The code above order the object that enters in my list, but the biggest ones is in the end of the list. Is there a way to reverse the order?

playersFastAdapter.itemAdapter.withComparator(compareBy({ it.player.goals }, {it.player.assists}), true)

Useful question about sorting in Kotlin: https://stackoverflow.com/questions/33640864/how-to-sort-based-on-compare-multiple-values-in-kotlin — BakaWaii, Sep 22 '17 at 16:17

score 6 · Answer 1 · edited Jan 21 '19 at 16:45

6

mylist.sortWith(compareBy<Player> { it.name }.thenBy { it.age }.thenBy { it.gender })

or

mylist.sortWith(compareByDescending<Player> { it.name }
    .thenByDescending { it.age }.thenBy { it.gender })

edited Jan 21 '19 at 16:45

CoolMind

answered Aug 07 '18 at 05:00

peter

2

Please format your code properly. And put some explanation on the code, instead of dumping the code alone – Jayendran Aug 07 '18 at 05:16
I formatted the code, but not sure it works right. At least, it returns `Unit` instead of list. Better see https://stackoverflow.com/a/37259482/2914140. – CoolMind Jan 21 '19 at 16:48

score 2 · Accepted Answer · answered Sep 22 '17 at 16:21

2

Changed to compareBy({ -it.player.goals}, {-it.player.assists})

And now it's working the way I wanted!

answered Sep 22 '17 at 16:21

score 0 · Answer 3 · answered Sep 22 '17 at 16:10

0

you can always use compareByDescending

answered Sep 22 '17 at 16:10

James Ralston

1

Thanks for the help, but looks like compareByDescending do not support more than one field on the comparison. – Guilherme Lima Pereira Sep 22 '17 at 16:14

3 Answers3