Class 'double' has no instance method 'sort'-CodePudding

I receive the following NoSuchMethodError in my code:

I/flutter (22695): {nom: CLINIQUE CENTRE, latitude: 37.4259071, longitude: -122.1095606, distance: 0}
I/flutter (22695): latitude  de :  CLINIQUE CENTRE37.4259071
I/flutter (22695): {nom: CLINIQUE CHATEAU, latitude: 37.4420794, longitude: -122.1432758, distance: 0}
I/flutter (22695): latitude  de :  CLINIQUE CENTRE37.4259071
I/flutter (22695): NoSuchMethodError: Class 'double' has no instance method 'sort'.
I/flutter (22695): Receiver: 2.298635770797528
I/flutter (22695): Tried calling: sort(Closure: (dynamic, dynamic) => dynamic)

I want de get distance wetween two locations

import 'package:flutter/material.dart';
import 'package:geolocator/geolocator.dart';
import 'package:flutter_sorting_location/Utils.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
import 'package:flutter_sorting_location/Destination.dart';

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  double? distance;
  List destinations = [];

  Position? _currentPosition;
  List<Destination> destinationlist = [];

  Future<List> getData() async {
    var url = 'http://aidemens.global-aeit.com/flutter/getlocation.php';
    print(url);
    final response = await http.get(Uri.parse(url));
    // print(json.decode(response.body));
    destinations = json.decode(response.body);
    return json.decode(response.body);
  }

  @override
  void initState() {
    _getCurrentLocation();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("Location sorting from current location"),
        ),
        body: FutureBuilder<List>(
            future: getData(),
            builder: (context, snapshot) {
              if (snapshot.hasError) print(snapshot.error);
              return snapshot.hasData
                  ? ListView.builder(
                      itemCount: snapshot.data!.length,
                      itemBuilder: (context, index) {
                        // print(snapshot.data!);
                        return Card(
                          margin: EdgeInsets.all(5),
                          elevation: 5,
                          child: Padding(
                            padding: EdgeInsets.all(5),
                            child: Container(
                              height: 40,
                              color: Colors.white,
                              child: Column(
                                children: [
                                  Text("${snapshot.data![index]['nom']}"),
                                  Text(
                                      "${double.parse(snapshot.data![index]['distance']!).toStringAsFixed(2)} km"),
                                ],
                              ),
                            ),
                          ),
                        );
                      })
                  : const Center(
                      child: Text(
                        "Aucun encaissement ce jour",
                        style: TextStyle(color: Colors.red),
                      ),
                    );
            }));
  }

  // get Current Location
  _getCurrentLocation() {
    Geolocator.getCurrentPosition(
            desiredAccuracy: LocationAccuracy.best,
            forceAndroidLocationManager: true)
        .then((Position position) {
      distanceCalculation(position);
      setState(() {
        _currentPosition = position;
      });
    }).catchError((e) {
      print(e);
    });
  }

  List tmp = [];

  distanceCalculation(Position position) {
    tmp.clear();
    for (var d in destinations) {
      if (destinations.isNotEmpty) {
        tmp.add(d);
      }
      destinations = tmp;
      print(d);

      //  for (var i = 0; i < destinations.length; i  ) {
      // print("latitude  : "   destinations[d]['latitude'].toDouble());
      var km = getDistanceFromLatLonInKm(
          position.latitude,
          position.longitude,
          double.parse(destinations[0]['latitude']),
          double.parse(destinations[0]['longitude']));
      // var m = Geolocator.distanceBetween(position.latitude,position.longitude, d.lat,d.lng);
      // d.distance = m/1000;

      destinations[0]['distance'] = km;
      // d.distance = km;
      //print("distance : ${d.distance}");
      // print("distance : ${destinations[0]['distance']}");
      //destinations.add(d);
      //print(d);
      // print("distance 2 : ${destinations[0]['distance']}");
      /*
      print(getDistanceFromLatLonInKm(
          position.latitude,
          position.longitude,
          destinations[0]['latitude'].toDouble(),
          destinations[0]['longitude'].toDouble()));
          */
      print("latitude  de :  "  
          destinations[0]['nom']  
          destinations[0]['latitude']);
    }

    setState(() {
      destinations[0]['distance'].sort((a, b) {
        return a.double.parse(destinations[0]['distance'])
            .compareTo(b.double.parse(destinations[0]['distance']) as double);
      });
    });
  }
}

Utils.dart

import'dart:math' as Math;

//HaverSine formula
double getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {
  var R = 6371; // Radius of the earth in km
  var dLat = deg2rad(lat2-lat1);  // deg2rad below
  var dLon = deg2rad(lon2-lon1);
  var a =
      Math.sin(dLat/2) * Math.sin(dLat/2)  
          Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *
              Math.sin(dLon/2) * Math.sin(dLon/2)
  ;
  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
  var d = R * c; // Distance in km
  return d;
}

double deg2rad(deg) {
  return deg * (Math.pi/180);
}

my dbb

CREATE TABLE `adherent` (
  `id` int(11) NOT NULL,
  `nom` varchar(100) NOT NULL,
  `latitude` double NOT NULL,
  `longitude` double NOT NULL,
  `distance` double NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Déchargement des données de la table `adherent`
--

INSERT INTO `adherent` (`id`, `nom`, `latitude`, `longitude`, `distance`) VALUES

(25, 'wwwwwwwwwwww', 37.4259071, -122.1095606, 0),
(35, 'xxxxxxxxxxx',  37.4420794, -122.1432758, 0);

code php

 $db_datas = array();
  $sql12 = "SELECT A.nom,A.latitude,A.longitude,A.distance
            FROM adherent A
            WHERE A.id IN(25,35)
    ";
    $results = $conn->query($sql12);
    
    if($results->num_rows >0){
        while($row = $results->fetch_assoc()){
            $db_datas[] = $row;
        }//fin while
         //Retourn toutes les reponses en json
         echo json_encode(utf8ize($db_datas));
    }else{
        echo "erreur";  
    }

CodePudding user response：

this destinations[0]['distance'] returns double so the error is correct here

setState(() {
      destinations[0]['distance'].sort((a, b) {
        return a.double.parse(destinations[0]['distance'])
            .compareTo(b.double.parse(destinations[0]['distance']) as double);
      });
});

CodePudding user response：

Here you added a double value and trying to sort it

destinations[0]['distance'].sort((a, b) {
        return a.double.parse(destinations[0]['distance'])
            .compareTo(b.double.parse(destinations[0]['distance']) as double);
      });

destinations[0]['distance'] is a double value.. You should be sorting destinations like


destinations.sort((a, b) {
        return (double.parse(a['distance'])).compareTo(double.parse(b['distance']));
      });

CodePudding user response：

now

I/flutter (24786): http://xxxxxxxxxxx/flutter/getlocation.php I/flutter (24786): {nom: CLINIQUE CENTRE, latitude: 37.4259071, longitude: -122.1095606, distance: 0} I/flutter (24786): latitude de : CLINIQUE CENTRE37.4259071 I/flutter (24786): {nom: CLINIQUE CHATEAU, latitude: 37.4420794, longitude: -122.1432758, distance: 0} I/flutter (24786): latitude de : CLINIQUE CENTRE37.4259071 I/flutter (24786): type 'String' is not a subtype of type 'num' of 'other'

List tmp = [];

  distanceCalculation(Position position) {
    tmp.clear();
    for (var d in destinations) {
      if (destinations.isNotEmpty) {
        tmp.add(d);
      }
      destinations = tmp;
      print(d);

      //  for (var i = 0; i < destinations.length; i  ) {
      // print("latitude  : "   destinations[d]['latitude'].toDouble());
      var km = getDistanceFromLatLonInKm(
          position.latitude,
          position.longitude,
          double.parse(destinations[0]['latitude']),
          double.parse(destinations[0]['longitude']));
      // var m = Geolocator.distanceBetween(position.latitude,position.longitude, d.lat,d.lng);
      // d.distance = m/1000;

      destinations[0]['distance'] = km;
      // d.distance = km;
      //print("distance : ${d.distance}");
      // print("distance : ${destinations[0]['distance']}");
      //destinations.add(d);
      //print(d);
      // print("distance 2 : ${destinations[0]['distance']}");
      /*
      print(getDistanceFromLatLonInKm(
          position.latitude,
          position.longitude,
          destinations[0]['latitude'].toDouble(),
          destinations[0]['longitude'].toDouble()));
          */
      print("latitude  de :  "  
          destinations[0]['nom']  
          destinations[0]['latitude']);
    }

    setState(() {
      destinations.sort((a, b) {
        return a['distance'].compareTo(b['distance']);
      });
    });
  }

CodePudding user response：

error now

type 'double' is not a subtype of type 'String'

setState(() {
      destinations.sort((a, b) {
        return double.parse(a['distance'])
            .compareTo(double.parse(b['distance']));
      });
    });