我正在尝试构建一个应用程序。
我使用的是官方google_maps_flutter。我对它没有任何问题，它已正确配置并且工作正常。
但我的问题是，当用户移动地图（不打字，移动）时，我需要知道地图的经纬度。
工作流程我需要一种属性'onMapMoved'，当用户移动地图时执行一个方法（问题1），然后获取用户移动地图的新纬度和经度（问题2）。
我浏览了官方文档，但找不到任何相关内容，只能使用坐标移动相机（我不知道如何从地图中心获得）。
我将不胜感激！ 非常感谢！
【问题讨论】：
标签： google-maps flutter
这是实现它的方法，
总之就是相关代码
void _onCameraMove(CameraPosition position) {
_lastMapPosition = position.target;
}
_onAddMarkerButtonPressed() {
_markers.clear();
setState(() {
_markers.add(Marker(
markerId: MarkerId(_lastMapPosition.toString()),
position: _lastMapPosition,
infoWindow: InfoWindow(title: _title, snippet: _detail),
icon: BitmapDescriptor.defaultMarker));
});
}
这里是完整代码，包含所有通常需要的东西，
import 'dart:async';
import 'package:bazar/assets/colors/ThemeColors.dart';
import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
import 'package:geocoder/geocoder.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:sliding_up_panel/sliding_up_panel.dart';
class LocationScreen extends StatefulWidget {
@override
_LocationChooserState createState() => _LocationChooserState();
}
class _LocationChooserState extends State<LocationScreen> {
Completer<GoogleMapController> _controller = Completer();
static const LatLng _center = const LatLng(45.343434, -122.545454);
final Set<Marker> _markers = {};
LatLng _lastMapPosition = _center;
MapType _currentMapType = MapType.normal;
String _title = "";
String _detail = "";
TextEditingController _lane1;
TextEditingController _lane2;
TextEditingController _lane3;
@override
void initState() {
super.initState();
_lane1 = new TextEditingController();
}
@override
Widget build(BuildContext context) {
double _height = MediaQuery.of(context).size.height;
double _width = MediaQuery.of(context).size.width;
return SafeArea(
child: Scaffold(
resizeToAvoidBottomPadding: true,
body: Stack(
children: [
GoogleMap(
mapToolbarEnabled: false,
// myLocationEnabled: true,
// myLocationButtonEnabled:true,
zoomControlsEnabled: false,
onMapCreated: _onMapCreated,
initialCameraPosition:
CameraPosition(target: _center, zoom: 11.0),
markers: _markers,
mapType: _currentMapType,
onCameraMove: _onCameraMove,
onTap: _handleTap,
),
Padding(
padding: EdgeInsets.all(20),
child: Align(
alignment: Alignment.topRight,
child: Column(
children: <Widget>[
_customButton(
FontAwesomeIcons.map, _onMapTypeButtonPressed),
SizedBox(
height: 15,
),
_customButton(
FontAwesomeIcons.mapMarker, _onAddMarkerButtonPressed),
SizedBox(
height: 5,
),
_customButton(FontAwesomeIcons.mapPin, _getUserLocation),
],
),
),
),
SlidingUpPanel(
minHeight: _height * 0.05,
maxHeight: _height * 0.4,
panel: Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Container(
height: 4,
width: _width * 0.2,
color: Orange,
),
SizedBox(
height: 10,
),
Container(
color: White,
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: [
Container(
height: _height * 0.2,
width: _width,
color: White,
child: TextField(
maxLines: 4,
controller: _lane1,
decoration: InputDecoration(
focusedBorder: OutlineInputBorder(
borderRadius:
BorderRadius.all(Radius.circular(4)),
borderSide:
BorderSide(width: 1, color: Orange),
),
errorBorder: OutlineInputBorder(
borderRadius:
BorderRadius.all(Radius.circular(4)),
borderSide:
BorderSide(width: 1, color: Maroon),
),
errorStyle: TextStyle(
color: Orange.withOpacity(0.5)),
labelStyle: TextStyle(
color: Orange.withOpacity(0.5)),
labelText: "Address "),
cursorColor: Orange,
),
),
],
),
),
SizedBox(
height: 10,
),
Container(
child: InkWell(
onTap: () {
debugPrint("Save Address");
},
child: Container(
alignment: Alignment.center,
width: _width * 0.3,
height: 40,
padding: EdgeInsets.only(
left: 10, right: 10, top: 6, bottom: 6),
decoration: BoxDecoration(
color: Orange,
borderRadius: BorderRadius.circular(12)),
child: Text(
"Save",
style: TextStyle(
color: White,
fontSize: 20,
fontWeight: FontWeight.bold),
),
),
),
)
],
),
),
body: null)
],
),
// floatingActionButton: FloatingActionButton.extended(
// onPressed: _goToTheLake,
// label: Text('To the lake!'),
// icon: Icon(Icons.directions_boat),
// ),
),
);
}
void _onMapCreated(GoogleMapController controller) {
_controller.complete(controller);
}
void _onCameraMove(CameraPosition position) {
_lastMapPosition = position.target;
}
_customButton(IconData icon, Function function) {
return FloatingActionButton(
heroTag: icon.codePoint,
onPressed: function,
materialTapTargetSize: MaterialTapTargetSize.padded,
backgroundColor: White,
child: Icon(
icon,
size: 16,
color: Maroon,
),
);
}
_onMapTypeButtonPressed() {
setState(() {
_currentMapType = _currentMapType == MapType.normal
? MapType.satellite
: MapType.normal;
});
}
_onAddMarkerButtonPressed() {
_markers.clear();
setState(() {
_markers.add(Marker(
markerId: MarkerId(_lastMapPosition.toString()),
position: _lastMapPosition,
infoWindow: InfoWindow(title: _title, snippet: _detail),
icon: BitmapDescriptor.defaultMarker));
});
}
_handleTap(LatLng point) {
_markers.clear();
_getLocation(point);
setState(() {
_markers.add(Marker(
markerId: MarkerId(point.toString()),
position: point,
infoWindow: InfoWindow(title: _title, snippet: _detail),
icon: BitmapDescriptor.defaultMarkerWithHue(BitmapDescriptor.hueOrange),
));
});
}
_getLocation(LatLng point) async {
final coordinates = new Coordinates(point.latitude, point.longitude);
var addresses =
await Geocoder.local.findAddressesFromCoordinates(coordinates);
var first = addresses.first;
print("${first.featureName} : ${first.addressLine}");
setState(() {
_title = first.featureName;
_detail = first.addressLine;
_lane1.text = _title + " " + _detail;
});
}
_getUserLocation() async {
Position position = await Geolocator()
.getCurrentPosition(desiredAccuracy: LocationAccuracy.high);
final coordinates = new Coordinates(position.latitude, position.longitude);
var addresses =
await Geocoder.local.findAddressesFromCoordinates(coordinates);
var first = addresses.first;
print("${first.featureName} : ${first.addressLine}");
final GoogleMapController controller = await _controller.future;
controller.animateCamera(
CameraUpdate.newCameraPosition(
CameraPosition(
target: LatLng(position.latitude, position.longitude), zoom: 16),
),
);
setState(() {
_title = first.featureName;
_detail = first.addressLine;
_lane1.text = _title + " " + _detail;
});
}
}
希望对您有所帮助，我有一个添加标记的按钮，您可以根据需要在旅途中轻松制作。
【讨论】：
如果您有一个名为 _controller 的 Completer：
Completer<GoogleMapController> _controller = Completer();
Future<LatLng> getCenter() async {
final GoogleMapController controller = await _controller.future;
LatLngBounds visibleRegion = await controller.getVisibleRegion();
LatLng centerLatLng = LatLng(
(visibleRegion.northeast.latitude + visibleRegion.southwest.latitude) / 2,
(visibleRegion.northeast.longitude + visibleRegion.southwest.longitude) / 2,
);
return centerLatLng;
}
以下是如何称呼未来：
LatLng _currentCenter = await getCenter();
【讨论】：