android - 如何从纬度和经度按升序对距离进行排序

Question

这里我通过脚本从服务器下载了地点数据，现在我想使用毕达哥拉斯按照距离的升序对 Place 列表进行排序

private class chargeur extends AsyncTask<Void, Void, List<Place>> {

        @Override
        protected List<Place> doInBackground(Void... voids) {
            List<Place> pl = new ArrayList<>();
            URL adresse = null;

            try {
                HttpsURLConnection cnx = Connecteur.connecter("get_all_places.php");
                BufferedReader B = new BufferedReader(new InputStreamReader(cnx.getInputStream()));
                String reponse = "";
                String lign = "";
                while ((lign = B.readLine())!=null) {
                    reponse+= lign;
                }

                JSONArray tab = new JSONArray(reponse);
                for (int i = 0; i<tab.length();i++) {
                    JSONObject obj = tab.getJSONObject(i);
                    String name = obj.getString("name");
                    String longitude = obj.getString("longitude");
                    String latitude = obj.getString("latitude");
                    Place p = new Place(name, longitude ,latitude);
                    pl.add(p);
                }
                return pl;
            } catch (Exception e) {}
        }
        // ...
}

Answer 1

你可以把它变成这样

Collections.sort(pl, new Comparator<Place>() {
    public int compare(Place pl1, Place pl2) {
        // Write your logic here.
        return Math.sqrt(pl1.longitude * pl1.longitude + pl1.latitude * pl1.latitude) < 
            Math.sqrt(pl2.longitude * pl2.longitude + pl2.latitude * pl2.latitude);
    }});