Question

I use a ListView with android.R.layout.simple_list_item_multiple_choice as list items. I want to sort the list (and maybe group the list) that checked items are on top of the list. I looked at the Comparator but it only lets me sort the list by the entries name of the list.
How could that be done in a nice way?

Answer 1

Its not true that a Comparator can only Compare Strings. You could just extend Comparator yourself and compare your Objects. So if Your Object is “smaller” return -1 and if it is “greater” return 1, if equal 0.
I’m asuming you have a simple Object representing a row of your list, lets say ListItem.
Then You write

public class ListItemComparator extends Comparator{
    public int compare(ListItem1 l1, ListItem2 l2){
        if(l1.isChecked && l2.isChecked) return 0;
        if(l1.isChecked && !l2.isChecked) return 1;
        else return -1;
        //or any other comparation you like
    }
    public boolean equals(ListItem1 l1, ListItem2 l2){
        //return true if compare returns 0
        return l1.isChecked && l2.isChecked;
    }
}

You could then sort your List with

Collections.sort(List<ListItem> items, Comparator comparator)

function and fill them with your ListItems and an Instance of your Comparator.
after that tell the Adapter that you changed his Content