Android按距离重新订购适配器

Question

我正在尝试按距离重新排序我的项目列表(使用android getListView,而不是自定义),我遇到了问题.

我使用适配器内的Maps Utils (SomeAdapter)获得以米为单位的球形距离(双倍).

double distance = SphericalUtil.computeDistanceBetween(fromCoord, toCoord);

但是在我填充适配器(AsyncTask)后,我需要在onPostExecute上缩短距离,我不知道.

    @Override
    protected void onPostExecute(Boolean result) {
        try {
            SQLiteHelper dbHelper = new SQLiteHelper(getActivity());
            pds = new SomeDataSource(dbHelper.db);

            ArrayList<Raids> some = pds.getAllRaids();

            SomeAdapter listViewAdapter = new SomeAdapter(getActivity(), some);
            getListView().setAdapter(listViewAdapter);

            SharedPreferences somename = context.getSharedPreferences("SomeName", Context.MODE_PRIVATE);
            Boolean UserOrder = somename.getBoolean("UserOrder", false);
            if (UserOrder){

            }

        } catch (SQLiteException | NullPointerException s) {
            Log.d("SomeName", "SomeFrag:", s);
        }
    }

谢谢

Answer 1

只需Comparable在您的Raids课程中实现界面-

class Raids implements Comparable<Raids> {
    private double distance;
    ...

    @Override
    public int compareTo(Raids instance2) {
        if (this.distance < instance2.distance)
            return -1;
        else if (this.distance > instance2.distance)
            return 1;
        else
            return 0;
    }
}

然后打电话Collections.sort给它 -

ArrayList<Raids> some = pds.getAllRaids();
Collections.sort(some);

并更新适配器 -

listViewAdapter.notifyDataSetChanged();