flutter - 如何从 Lat Long 值中获取地址并显示到文本字段中

Question

在我的项目中，我使用谷歌地图来获取我当前的位置。现在我想从 map 标记中获取地址并将该地址显示到文本字段，但我不明白该怎么做。我对编程很陌生。
下面是我的代码。我接下来该怎么做？

class _MyHomePageState extends State<MyHomePage> {

  LatLng _initialcameraposition = LatLng(20.5937, 78.9629);
  GoogleMapController _controller;
  Location _location = Location();

  void _onMapCreated(GoogleMapController _cntlr)
  {
    _controller = _cntlr;
    _location.onLocationChanged.listen((l) { 
      _controller.animateCamera(
        CameraUpdate.newCameraPosition(
          CameraPosition(target: LatLng(l.latitude, l.longitude),zoom: 15),
          ),
      );
    });
  }


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        height: MediaQuery.of(context).size.height,
        width: MediaQuery.of(context).size.width,
        child: Stack(
          children: [
            GoogleMap(
              initialCameraPosition: CameraPosition(target: _initialcameraposition),
              mapType: MapType.normal,
              onMapCreated: _onMapCreated,
              myLocationEnabled: true,
            ),
          ],
        ),
      ),
    );
  } 
}

Answer 1

您必须使用地理编码器包 ( check description of geocoder package ) 从 LatLang 值中获取地址。并使用 Geolocator 包 ( Check Description of Geolocator pacakge here ) 从设备获取当前位置。
试试这个代码:

import 'package:flutter/material.dart';
import 'dart:async';
import 'package:permission_handler/permission_handler.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:geocoder/geocoder.dart';

void main() {
  runApp(MaterialApp(home: MyHomePage()));
}

class MyHomePage extends StatefulWidget{
  @override
  State createState() {
    // TODO: implement createState
    return MyHomePageState();
  }

}

class MyHomePageState extends State{

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      body: MyMap(),
    );
  }
}
class MyMap extends StatefulWidget{

  @override
  State createState() {
    // TODO: implement createState
    return MyMapState();
  }
}

class MyMapState extends State{
  LatLng latlong=null;
  CameraPosition _cameraPosition;
  GoogleMapController _controller ;
  Set<Marker> _markers={};
  TextEditingController locationController = TextEditingController();
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    _cameraPosition=CameraPosition(target: LatLng(0, 0),zoom: 10.0);
    getCurrentLocation();
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return SafeArea(child: Stack(
      children: [
        (latlong!=null) ?GoogleMap(
          initialCameraPosition: _cameraPosition,
          onMapCreated: (GoogleMapController controller){
            _controller=(controller);
            _controller.animateCamera(

                CameraUpdate.newCameraPosition(_cameraPosition));
          },

          markers:_markers ,

        ):Container(),
        Positioned(
          top: 50.0,
          right: 15.0,
          left: 15.0,
          child: Container(
            height: 50.0,
            width: double.infinity,
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(3.0),
              color: Colors.white,
              boxShadow: [
                BoxShadow(
                    color: Colors.grey,
                    offset: Offset(1.0, 5.0),
                    blurRadius: 10,
                    spreadRadius: 3)
              ],
            ),
            child: TextField(
              cursorColor: Colors.black,
              controller: locationController,
              decoration: InputDecoration(
                icon: Container(
                  margin: EdgeInsets.only(left: 20, top: 0),
                  width: 10,
                  height: 10,
                  child: Icon(
                    Icons.location_on,
                    color: Colors.green,
                  ),
                ),
                hintText: "pick up",
                border: InputBorder.none,
                contentPadding: EdgeInsets.only(left: 15.0, top: 12.0),
              ),
            ),
          ),
        ),
      ],
    ));
  }
  Future getCurrentLocation() async {
    LocationPermission permission = await Geolocator.checkPermission();
    if (permission != PermissionStatus.granted) {
      LocationPermission permission = await Geolocator.requestPermission();
      if (permission != PermissionStatus.granted)
        getLocation();
      return;
    }
    getLocation();
  }
  List<Address> results = [];
  getLocation() async
  {
    Position position = await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.high);
    print(position.latitude);
    setState(() {
      latlong=new LatLng(position.latitude, position.longitude);
      _cameraPosition=CameraPosition(target:latlong,zoom: 10.0 );
      if(_controller!=null)
        _controller.animateCamera(

            CameraUpdate.newCameraPosition(_cameraPosition));
      _markers.add(Marker(markerId: MarkerId("a"),draggable:true,position: latlong,icon: BitmapDescriptor.defaultMarkerWithHue(

          BitmapDescriptor.hueBlue),onDragEnd: (_currentlatLng){
        latlong = _currentlatLng;

      }));
    });

    getCurrentAddress();
  }

getCurrentAddress() async
{

  final coordinates = new Coordinates(latlong.latitude, latlong.longitude);
  results  = await Geocoder.local.findAddressesFromCoordinates(coordinates);
  var first = results.first;
  if(first!=null) {
    var address;
    address = first.featureName;
    address =   " $address, ${first.subLocality}" ;
    address =  " $address, ${first.subLocality}" ;
    address =  " $address, ${first.locality}" ;
    address =  " $address, ${first.countryName}" ;
    address = " $address, ${first.postalCode}" ;
   
    locationController.text = address;
  }
}
}