將坐標 Latlng 從 map 小部件傳遞到同一屏幕中的 Void function

Question

我是 Flutter 世界和移動應用程序開發的新手，並且正在為如何在我的應用程序中傳遞數據而苦苦掙扎。 This is my code, How can I pass Latlng cordinate from the google map widget (when I press the map and get a new marker) to the parameter Coord of Addlocation function and converted them from Latlng to double , because the map widget returns the coordinates在Latlng類型和我的Location class 中，坐標是double 。 請幫忙。

import 'dart:async';
import 'dart:convert';
import 'dart:html';
import 'dart:math';
import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:rounded_loading_button/rounded_loading_button.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:sidebar_animation/Models/Location.dart';
import 'package:sidebar_animation/Services/DataHelpers.dart';
import 'package:http/http.dart' as http;

class AddLocation extends StatefulWidget {
  AddLocation({Key key, this.title}) : super(key: key);
  final String title;
  @override
  AddLocationState createState() => AddLocationState();
}

class AddLocationState extends State<AddLocation> {
  GoogleMapController _controller;
  final CameraPosition _initialPosition =
      CameraPosition(target: LatLng(24.903623, 67.198367));
  final List<Marker> markers = [];
  bool _isLoading = false;
  bool t3ada = false;
  bool faregh = false;
  final RoundedLoadingButtonController _btnController =
      new RoundedLoadingButtonController();
  final TextEditingController sitenameController = new TextEditingController();
  final TextEditingController descriptionController =
      new TextEditingController();

  addMarker(cordinate) {
    int id = Random().nextInt(1);
    setState(() {
      markers
          .add(Marker(position: cordinate, markerId: MarkerId(id.toString())));
    });
  }

  @override
  Widget build(BuildContext context) {
    final _key = GlobalKey<FormState>();
    return Scaffold(
      body: Stack(
        children: [
          Column(
            children: [
              Form(
                key: _key,
                child: Column(
                  children: <Widget>[
                    Container(
                      padding: EdgeInsets.all(8.0),
                      decoration: BoxDecoration(
                          border: Border(
                              bottom: BorderSide(color: Colors.grey[100]))),
                      child: TextFormField(
                        validator: (value) {
                          if (value.isEmpty) {
                            return "Site name cannot be empty !";
                          } else
                            return null;
                        },
                        controller: sitenameController,
                        decoration: InputDecoration(
                            icon: Icon(Icons.place, color: Colors.grey[400]),
                            border: InputBorder.none,
                            hintText: "Site name",
                            hintStyle: TextStyle(color: Colors.grey[400])),
                      ),
                    ),
                    Container(
                      padding: EdgeInsets.all(8.0),
                      decoration: BoxDecoration(
                          border: Border(
                              bottom: BorderSide(color: Colors.grey[100]))),
                      child: TextFormField(
                        validator: (value) {
                          if (value.isEmpty) {
                            return "Description cannot be empty !";
                          } else
                            return null;
                        },
                        controller: descriptionController,
                        decoration: InputDecoration(
                            icon: Icon(Icons.email, color: Colors.grey[400]),
                            border: InputBorder.none,
                            hintText: "Description",
                            hintStyle: TextStyle(color: Colors.grey[400])),
                      ),
                    ),
                  ],
                ),
              ),
              Expanded(
                child: GoogleMap(
                  initialCameraPosition: _initialPosition,
                  mapType: MapType.normal,
                  onMapCreated: (controller) {
                    setState(() {
                      _controller = controller;
                    });
                  },
                  markers: markers.toSet(),
                  onTap: (cordinate) {
                    _controller
                        .animateCamera(CameraUpdate.newLatLng(cordinate));
                    addMarker(cordinate);
                  },
                ),
              ),
              SizedBox(
                height: 30,
              ),
              buttonSection(),
            ],
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          _controller.animateCamera(CameraUpdate.zoomOut());
        },
        child: Icon(Icons.zoom_out),
      ),
    );
  }

  DatabaseHelper2 databaseHelper2 = new DatabaseHelper2();
  final _key = GlobalKey<FormState>();
  void _doSomething() async {
    Timer(Duration(seconds: 1), () {
      print("button pressed ");
      print(" Site name" + sitenameController.text);
      print(" description" + descriptionController.text);
      print(" Coordinates" + Coord.toString());
      _btnController.stop();
      Addlocation(sitenameController.text, Coord, descriptionController.text);
      _btnController.stop();
    });
  }

  void Addlocation(String sitename, double Coord, String description) async {
    final prefs = await SharedPreferences.getInstance();
    final key = 'token';
    final value = prefs.get(key) ?? 0;
    var jsonResponse = null;
    String myUrl = DatabaseHelper2.serverUrl + "/location/Add?token=" + value;
    http.Response response = await http.post(myUrl, headers: {
      'Accept': 'application/json',
      //'Authorization': 'token $value'
    }, body: {
      "SiteName": "$sitename",
      "Coordinates": "$Coord",
      "Description": "$description",
    }).then((response) {
      print('Response status : ${response.statusCode}');
      print('Response body : ${response.body}');
    });
    print(response.body);
  }

  buttonSection() {
    return Container(
      height: 50,
      child: AspectRatio(
        child: RoundedLoadingButton(
          color: Colors.amberAccent,
          child: Text("Add", style: TextStyle(color: Colors.white)),
          controller: _btnController,
          onPressed: _doSomething,
        ),
        aspectRatio: 8,
      ),
    );
  }
}

這是我的 class位置

// To parse this JSON data, do
//
//     final location = locationFromJson(jsonString);

import 'dart:convert';

List<Location> locationFromJson(String str) => List<Location>.from(json.decode(str).map((x) => Location.fromJson(x)));

String locationToJson(List<Location> data) => json.encode(List<dynamic>.from(data.map((x) => x.toJson())));

class Location {
  Location({
    this.automaticIrrigation,
    this.coordinates,
    this.createdDate,
    this.sensorIds,
    this.id,
    this.siteName,
    this.description,
    this.v,
  });

  bool automaticIrrigation;
  List<double> coordinates;
  DateTime createdDate;
  List<String> sensorIds;
  String id;
  String siteName;
  String description;
  int v;

  factory Location.fromJson(Map<String, dynamic> json) => Location(
    automaticIrrigation: json["AutomaticIrrigation"],
    coordinates: List<double>.from(json["Coordinates"].map((x) => x.toDouble())),
    createdDate: DateTime.parse(json["Created_date"]),
    sensorIds: List<String>.from(json["Sensor_ids"].map((x) => x)),
    id: json["_id"],
    siteName: json["SiteName"],
    description: json["Description"],
    v: json["__v"],
  );

  Map<String, dynamic> toJson() => {
    "AutomaticIrrigation": automaticIrrigation,
    "Coordinates": List<dynamic>.from(coordinates.map((x) => x)),
    "Created_date": createdDate.toIso8601String(),
    "Sensor_ids": List<dynamic>.from(sensorIds.map((x) => x)),
    "_id": id,
    "SiteName": siteName,
    "Description": description,
    "__v": v,
  };
}

最后，我需要從 map 小部件獲取坐標到 Addlocation function 並將它們從 Latlng 轉換為 Double。

Answer 1

檢查此代碼，它與您的案例位置 model 相似（放置模型）

import 'dart:io';
import 'package:flutter/foundation.dart';

class PlaceLocation {
  final double latitude;
  final double longitude;
  final String address;
  const PlaceLocation({
    @required this.latitude,
    @required this.longitude,
    this.address,
  });
}

class Place {
  final String id;
  final String title;
  final location;
  final File image;

  Place({
    @required this.id,
    @required this.title,
    @required this.location,
    @required this.image,
  });
}

import 'dart:io';

import 'package:flutter/foundation.dart';

import '../models/place.dart';
final updatedLocation = PlaceLocation(
    latitude: pickedLocation.latitude,
    longitude: pickedLocation.longitude,
    address: address);
 final newPlace = Place(
      id: DateTime.now().toIso8601String(),
      title: pickedTitle,
      location: updatedLocation,
      image: pickedImage,
    );

    _items.add(newPlace);