排序arraylist。 整数值比较

Question

I'd like to sort my Listview by int value. I've looked in similar questions and solutions and have done something like this but it is not sorting listView descending (nothing happens btw). In arrayList are objects which this object has field named "rating". Here is a code:

public class GifModel implements Comparable<GifModel>, Comparator<Integer>{
.......
.......

@Override
    public int compare(Integer lhs, Integer rhs) {
        // TODO Auto-generated method stub
        return lhs.intValue() > rhs.intValue() ? 1:0;
    }

}

And in main activity. "ratingSort" is a List:

ratingSort = new ArrayList<GifModel>(list);

    Collections.sort(ratingSort, new Comparator<GifModel>() {
        @Override
        public int compare(GifModel lhs, GifModel rhs) {
        return lhs.compare(lhs.getRating(),rhs.getRating());
        }

        });

Answer 1

Change your sorting comparator to this and you should be good to go:

Collections.sort(ratingSort, new Comparator<GifModel>() {

    @Override
    public int compare(GifModel lhs, GifModel rhs) {
        if (lhs.getRating() < rhs.getRating())
            return -1;
        else if (lhs.getRating() > rhs.getRating())
            return 1;
        return 0;
    }

});

Answer 2

You don't want to sort the listview, but the collection which you are adapting to it. You can do a simple Comparator() to accomplish so.

Answer 3

For your requirement, it is redundant to make your GifModel impl. Comparator , if it has already impl. Comparable<GifModel> .

You can just implement the compareTo(GifModel o) method, and there compare the gifModelObj.getRating() thus you can just Collections.sort(ratingSort)

If you had requirements like sorting the list by any possible field of GifModel , you can let your GifModel implement neither Comparator nor Comparable. And create a number of Comparators for the sorting.