How to sort a cursor with variables in android?

Question

I have a ListView (in a ListFrament) with a CursorAdapter which shows different names of places. At the begining, the list was sorted by this names (using ORDER_BY in my query).

Now, I have added to my item_row.xml a TextView containing the distance of the place from the user's position thanks to the latitude/longitude of each place and the LocationManager. And I would like to sort my list of places by this distance (from the nearest to the farthest).

The problem is that I calculate the distance outside the "SQL environment", and there are no methods to sort my Cursor/ListView/Adapter...

Any ideas ?

Answer 1

Use Collections.sort(List, Comparator) with a custom Comparator.

Example using a class A sorting by the sum of both integer fields:

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

class A {
    final String name;
    final int someNumber;
    final int someOtherNumber;

    A(final String name, final int a, final int b) {
        this.name = name;
        this.someNumber = a;
        this.someOtherNumber = b;
    }

    @Override
    public String toString() {
        return this.name;
    }
}

class YourComparator implements Comparator<A> {
    @Override
    public int compare(A o1, A o2) {
        final int sumO1 = o1.someNumber + o1.someOtherNumber;
        final int sumO2 = o2.someNumber + o2.someOtherNumber;
        return (sumO1 - sumO2);
    }
}

public class Main {
    public static void main(final String args[]) {
        final List<A> listOfAs = new ArrayList<A>();
        listOfAs.add(new A("Three", 1, 2));
        listOfAs.add(new A("Two", 1, 1));
        listOfAs.add(new A("Ten", 3, 7));
        listOfAs.add(new A("Five", 3, 2));
        Collections.sort(listOfAs, new YourComparator());
        System.out.println(listOfAs);
    }
}